Revion

 

Selected technical articles pulled from past issues of the North Star Bavarian.

   
  •   What’s The Best Way to Clean My Engine?
  •   H31 system power braking System
  •   Winter Car Preparation
  •   More Than You Ever Wanted to Know About Motor Oil
  •   All Wheel (Xi) Sytem
  •   Failing M50 Water Pumps
  •   Winter Car Care
  •   Mechanical Over-Revs
  •   Brakes - Upgrades & Improvements
  •   Headlights - A Comparison
  •   Coils & Spark Plugs / Ignition systems
   
What’s The Best Way to Clean My Engine?

By Mike Miller

Cleaning your car's engine compartment is really not that difficult, all it takes is some elbow grease and common sense. Realizing that modern BMW engine compartments contain electronics approaching spacecraft proportions, one must be careful. With that said, you should use the least invasive method possible to clean the engine, according to how dirty it is.

One way is to use a regular garden hose, because it has less pressure and is less likely to open a seal on something electrical. A high-pressure stream of water or steam is more damaging and should be reserved for the dirtiest of dirt for that reason alone. Either way, it is critical that electrical components be hand-cleaned and covered with cellophane. Secure the cellophane with duct tape, and remove it after cleaning. If you're wondering what qualifies as an electrical component, you probably shouldn't be near your car's engine. But just in case, an electrical component is anything with an electrical cable going into it, like the lights, fuel pump, etc.

Engine cleaners such as Gunk, Simple Green, and Purple Stuff may be used with the same caveat: Keep the stuff away from electrical components. And after cleaning with water, it is best to blow-dry the engine compartment with compressed air. If you don't have an air compressor, you
can buy one cheap at Home Depot.

The least invasive, and therefore best way to clean a modern BMW engine compartment is by hand, using rags and cleaners - either Simple Green, Purple Stuff, or some type of solvent such as carburetor cleaner. Generally speaking, the harsher the product, the better it will clean. Gunk is not for hand cleaning, though. For rags, old garments work best. Save your old socks, skivvies, and especially bathrobes. Cut the latter into 12 by 12 inch sections.

Many have expressed concern that modern engine compartments are so tight, they can't be cleaned without water. This isn't so. They can be cleaned without water, but you'll have to remove a component or two so you can get your hands in there. (Please, don't write in asking what to remove. First, what to remove should be obvious from looking at the engine. Different cars are different. I don't know what to remove - I'm not looking at the engine! Second, this is another of those questions; if you have to ask, you probably shouldn't be messing around under the hood without direct supervision.)

If your bimmer was born before the E34, E36, E32, E31 era, clean your engine any way you want. You should still cover electrical components, though. Bear in mind that the M10, M20, and M30 engine families have spark plug recesses on the right side of the cylinder head, which can fill up with water. If this happens, the engine probably won't start. If it does start, it will have an ignition miss. This is no problem. Fire up your air compressor, fit the blowgun to the hose, remove the spark plug boots, and blow the water out of the spark plug recesses. It is always best to blow-dry an engine compartment after cleaning with water. Or at least drive the car for a few miles.

Some dealerships are telling owners that BMW engines must be protected from water. If this were true, we wouldn't be able to drive the cars in rain. Again, cleaning your engine compartment is all about common sense.

Mike Miller edits the TechTalk section in Roundel & is with the Boston Chapter

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Bavarian Technic

by Paul Dzimian


How I learned to stop worrying and love the bomb.
(From Stanley Kubrick's Dr. Strangelove)

This month I want to discuss a somewhat vintage BMW power brake system, the H31 "Hydro Boost" power brakes and steering system. BMW has always been a leader in technology and never was this more evident then when they introduced the H31 system in the E23 seven series cars in 1977. As is still typical the technology that was debut on the flagship Seven series became a proven design and used on various Five, Six and Seven series cars ending on the Eight series before being phased out with the last of the Eight Fifties in the mid nineties. Over the years I have received a great deal of calls and e-mails regarding the diagnosis and repair of this system. I will attempt to clarify some of the misconceptions and advise on accurate, straightforward diagnosis.

Unlike almost every other power assist braking system that uses engine vacuum to create the boost, the H31 system used hydraulic pressure from a special power steering pump to create the assist needed. This system allowed for more available assist that was highly controllable in a smaller package then any vacuum boost system available at that time. Soon after its introduction, BMW coupled its race proven BOSCH ABS technology to offer a braking system that became the performance standard that other manufactures where judged by.

Over the years the H31 system has caused a number of headaches for techs who where attempting to diagnosis this very sophisticated hydraulic system. Most of these headaches are due to a lack of understanding of the basic principles of operation. The original repair information involved the use of very high pressure gauges to test the pump output and the pressure controlled flow regulator known as the DS Regulator with it's attached accumulator better known as "the Bomb" because of it's cannonball shape. I have found the use of these gauges to be unnecessary in all but a few rare cases.

The most common failure of this system is the accumulator (the bomb). It is a round steel chamber with a high-pressure nitrogen filled balloon built inside it. On a normal working system, as the pumps hydraulic pressure builds up it moves fluid into one side of this sphere displacing the balloon and storing pressure and a volume of fluid. Over time the balloon loses its nitrogen charge causing the sphere to lose its spring affect of storing the pressure energy. The simple test of the bomb is to run the car for a minute to allow the pressures to normalize then shut off the engine and then pump the brake pedal until all power assist is lost and the pedal becomes hard. Typically a good accumulator will give you about eight pumps of the brake pedal before you loose assist. A bad one will be hard after one pump and the accumulator needs to be replaced. The second part of the test is to check the DS regulator. Again run the motor briefly to build pressure then shut it off. Now wait five minutes before applying the brakes. You should have at least half the pumps with assist that you had when you did the test the first time. If not the valves in the DS regulator are leaking down to quickly. The DS regulator cannot be serviced and would need to be replaced.

The common symptoms of a failed accumulator can be an intermittent brake warning light that can come on when the brakes are applied, or a too soft brake pedal that does not improve after bleeding the brake hydraulics. A good check for the brake hydraulics is to pump the pedal till all boost is gone, then if the pedal is still spongy then the problem is in the brakes. Other issues common to the booster system are leaking pressure switches at the DS regulator and leaks at the hydraulic booster. The brake booster leaking will vent power steering fluid (either ATF or Pentosin depending on the system) at a drain hole between the booster and the master cylinder.

The power steering pump supplying the pressure for this system has a maximum operating pressure of about 130 bar (1900 psi), however the working pressure for the H31 system is regulated at 35 ­ 57 bar and only needs about ten percent of the fluid volume that is needed for the power steering. With that in mind it is obvious that any problem with the pump pressure or volume would show itself first as a problem in the power steering.

To properly check the fluid level you must have the engine off, pump the brakes until the assist is gone then remove the cover from the reservoir. The fluid should be at the top of the screen. If not top off with the correct fluid for your car, most early cars used ATF but later BMW's went to Pentosin fluid, do not mix them and NEVER use brake fluid in the pump hydraulics. Brake fluid will destroy the seals in the H31 system and ATF or Pentosin will destroy the seals in the brake hydraulics. They are separate systems and do not share fluids, IF IN DOUBT ADD NOTHING. If either system is contaminated by the other it can be very expensive to fix and potentially dangerous.

My last set of problems, are usually listed as power steering complaints. This system uses a very high-pressure, high volume pump; any leaks in the system can be a big mess fast. Many of these cars develop noises in the pump and the pump is replaced only to find that the noise is still there! The problem is from air being pulled into the pump through loose hose connections on the inlet hose between the pump and the reservoir. The leak can be so small it will not lose any fluid but still allow air to be sucked in when the car is running. This problem is exaggerated by the fact that the filter in the reservoir has probably never been serviced and is plugging up with debris. Finally you must consider the condition of the drive belt, a belt failure will immediately cause a loss of power steering and the brakes will only have the stored pressure of the accumulator to assist you for stopping.

You can only imagine heading to the braking zone at turn three of BIR in your E28 M5 only to find that the belt broke. You would have no power steering and no power brakes if the accumulator were bad. No more M5, Bad day, really, really, bad day.

Until next time,

Paul Dzimian
BMW CCA TSA
Shop Forman
Motorwerks BMW

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Bavarian Technic

By Paul Dzimian

This is the time of year that we start to feel the last few warm and sunny days of the year slip away as the days get shorter and the nights get colder. Winter will be coming sooner than we may be ready for it so I wanted to update and reprint a article that I wrote in 97 on winter car preparation, driving and storage for BMW's.
Be Prepared

If you're not real familiar with your BMW take a little time before it gets nasty out to get to know where a few important things are. Like (for instance) the oil dipstick and the oil filler cap, the radiator cap. Do you know where the battery is? On many BMW's it is in the trunk, some have it under the rear seat; a few have the battery under the hood. There is not much more sad looking than a couple of guys standing out in a blizzard looking around under the hood for the battery and cannot find one. Most BMW's with the battery mounted someplace other then the engine compartment have remote battery posts under the hood, they are not always the easiest thing to find so look in your owners manual and then go find it on the car. You will thank me for this later. Do you have jumper cables, you should. I would recommend a little kit with a set of jumper cables a good flashlight a couple of space blankets, First Aid kit a rain poncho and of course a roll of duct tape.
Cooling System

A well maintained cooling system is never more important then during a Minnesota winter. The severe weather we see will turn a car breakdown from an annoyance into a dangerous situation. The obvious thing is to see that your antifreeze protection is sufficient. In this part of the world, your antifreeze should be set for -35deg. F protection or colder. This should be checked with a hydrometer or coolant test strip (more on this later) and corrected if necessary. A 50/50 mix of concentrated antifreeze to water will typically protect you to -34 degrees, 70% antifreeze/ 30% water will provide protection down to -84 degrees. This is the lowest that conventional antifreeze will go before freezing. At no time should the antifreeze concentration be set any higher because straight concentrated antifreeze will freeze at -8 degrees and also does a poor job of transferring heat out of the motor.

Fresh antifreeze is a combination of ethylene glycol (and an additives package of corrosion inhibitors and special lubricants to protect the cooling system and water pump) mixed with water. As antifreeze ages some very important things happen to its chemistry. Eventually heat, electricity and the combined effects of dissolved oxygen and minerals in the coolant will deplete these inhibitors. This will allow the ph of the coolant to shift from an alkaline to an acid solution that will cause corrosion and electrolytic damage in your motor! This is a very common problem on cars that have not had the coolant flushed correctly at regular intervals. BMW service intervals include inspecting the coolant and changing it every two or three years. The reserve alkalinity (pH) is tested with litmus paper and should be between nine and fourteen. Special test strips that measure both pH and the freeze point are available at the better auto parts stores. It is very important to check cars that will be stored for the winter before they are put away, even if they will be in heated storage.

Hoses and belts should be inspected; they do not last forever. Belts should have the proper tension to keep them from slipping, they should be free of any cracking or glazing on the working surface of the belt. Late model BMW's with the serpentine belts are particularly susceptible to a surprise failure because of high underhood temperatures and a self-tensioner that keeps them from making noise as they "go bad". These serpentine belts allow one or two belts to take the place of multiple v belts that needed to be adjusted on a regular basis in the old days. Hoses should be inspected for any signs of leakage or deterioration, keeping in mind that most hoses fail from the inside.

Thermostats maintain the correct temperature for both the passengers and the motor. If your thermostat is allowing your engine to run cooler then recommended the engine computer may never allow the fuel injection to work properly, causing poor fuel mileage, high emissions, poor performance and possibly fuel dilution in the motor oil. Typically, you would see this as a drop in engine temperature in cold weather, especially in highway driving. In the last few years BMW is using a computer controlled thermostat to allow for tighter control of engine temperature. This is done by building a "normal" thermostat that runs at a very high temperature. Incorporated in the design is a very small electric heating element that is controlled by the engine computer. By using the coolant temperature sensor as a feedback signal the engine computer can regulate the engine temperature by supplying current to this heating element as needed to cool the motor. Unfortunately BMW missed the mark in an early design of these thermostats on the six cylinder motors. An unacceptable level of failed thermostats has led to many cars being recalled to have the thermostat replaced with the newest design. Owners of affected vehicles will receive a notice in the mail from BMW.
Motor Oil

Oil is the most important fluid in your car. It lubricates the engine and is the first link in the chain of the cooling system by absorbing the heat of friction and transferring it into the rest of the engine where the heat is taken away by the cooling system. The oil also caries away the byproducts of combustion, such as dirt, water and residual fuel. The oil filter takes care of the dirt while the water and fuel are vented back to the intake when the engine is run at full operating temperature.

This is why short trip driving is so hard on oil. If the engine does not get to run at full operating temperature for a good length of time then moisture will start to build up in the oil, causing sludge to form. The best way to prevent this is frequent oil and filter changes. These days with the use of synthetic oils in all BMW cars, the oil service intervals in the free maintenance program are extended very long. Overall, this appears to be OK in mild climates where the daily drive cycle is long enough to vent off any moisture buildup. In a severe climate such as ours, or if you find you do many short trips, then more oil changes are called for. My recommendation is to do one or two oil and filter changes between the free oil services when the service indicator says it is due. Any car that will be stored for the winter should have the oil and filter changed right before it is put up for the winter. For several years now BMW uses synthetic oils exclusively. Synthetic oil is mandatory in the cars that came with it from the factory and I find it is far superior to any conventional oil- I recommend it in any BMW.
Wiper Blades

How are your wipers working? If they do not clean very well now then how well are they going to work in the first sleet storm? Wiper performance can be difficult to determine in the shop, If your car is in for service and you know the wipers didn't do a very good job in the rain tell them to replace the wiper inserts. Most aftermarket wipers are sold as a blade with a new metal frame, these are a generic design and do not do a very good job on the curvature of BMW glass. The original equipment wipers are designed to allow the rubber blade to be replaced and the rest of the frame to be reused; this is both good economy and good ecology. If you find that even with new wiper blades the windshield still does not clean properly or the wipers chatter on the glass, an old service tip from BMW is to clean the windshield with the household cleaner Bon Ami. The cleaner should be applied with a clean wet cloth and the windshield must be thoroughly and evenly scrubbed. Rinse off the residue and dry with a clean cloth.
Snow Tires

BMW has come a long way in improving its winter driving abilities in this age of electronics. From ABS brakes to the various generations of traction control starting with Anti Slip Control (ASC) on up to the newest Dynamic Stability Control (DSC) have been fantastic improvements. However the limiting factor in traction is still where the rubber meets the road. I believe in snow tires; "All Season" tires are a poor compromise in all seasons. They tend to perform poorly in the summer and are terrible in the winter. The "ice tire" technology of the top quality snow tires such as Michelin Alpin Ice and Bridgestone Blizzak's is greatly improved over snow tires of the past. In the low profile tires needed for most of the M cars the Michelin Alpin Pilot seams to be the favorite and from my experience I would have to agree. Many people like to use a second set of wheels to mount their snow tires on; this saves on the expense of mounting and balancing twice a year and allows for a much faster changeover from summer to winter tires. This also saves the nice summer wheels from the ravages of winter.

Storage

If you are one of those people that will be storing their BMW for the winter, here are some tips on proper storage.

· Change the oil and filter.

· Test antifreeze and service as needed.

· Fill the gas tank but do not "top off" the tank.

· Inflate tires to 55 psi.

· Clean the car thoroughly inside and out. Dry the car completely, also make sure that the brakes are dry.

· Use a breathable soft car cover.

· Get a couple of small bags of mouth balls. Punch a few holes in the bags and place one bag under the hood and the other bag on the floor under the car. This will discourage small rodents or insects from making your BMW their home.

· Remove the battery, store in a dry warm place and trickle charge.

· DO NOT put the car up on blocks. Cars should be supported by their tires and suspensions NOT jack stands.

· DO NOT set the hand brake. It could stick after sitting all winter and can be a bugger to free up. Better to use a couple of blocks of wood to keep the car from rolling.

· On manual transmission cars, put the car in second or fourth gear to prevent it from forming corrosion on the shift selector rod into the transmission.

Paul Dzimian
Motorwerks BMW
BMWCCA TSA
BMWTech@mn.rr.com
612-919-7385

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More Than You Ever Wanted to Know About Motor Oil

by Ed Hackett

[Ed is a chemical engineer who works for the University of Nevada's Desert Research facility -- Ed.]

Edits: v1.0 First there was 1.0. Before that there was darkness.

v1.1 Change in description of viscosity.

v1.2 Updated info on AMSOIL (courtesy of Morgan McArthur )

Choosing the best motor oil is a topic that comes up frequently in discussions between motoheads, whether they are talking about motorcycles or cars. The following article is intended to help you make a choice based on more than the advertising hype.

Oil companies provide data on their oils most often referred to as "typical inspection data". This is an average of the actual physical and a few common chemical properties of their oils. This information is available to the public through their distributors or by writing or calling the company directly. I have compiled a list of the most popular, premium oils so that a ready comparison can be made. If your favorite oil is not on the list get the data from the distributor and use what I have as a data base.

This article is going to look at six of the most important properties of a motor oil readily available to the public: viscosity, viscosity index (VI), flash point, pour point, % sulfated ash, and % zinc.

Viscosity is a measure of the "flowability" of an oil. More specifically, it is the property of an oil to develop and maintain a certain amount of shearing stress dependent on flow, and then to offer continued resistance to flow. Thicker oils generally have a higher viscosity, and thinner oils a lower viscosity. This is the most important property for an engine. An oil with too low a viscosity can shear and lose film strength at high temperatures. An oil with too high a viscosity may not pump to the proper parts at low temperatures and the film may tear at high rpm.

The weights given on oils are arbitrary numbers assigned by the S.A.E. (Society of Automotive Engineers). These numbers correspond to "real" viscosity, as measured by several accepted techniques. These measurements are taken at specific temperatures. Oils that fall into a certain range are designated 5, 10, 20, 30, 40, 50 by the S.A.E. The W means the oil meets specifications for viscosity at 0 F and is therefore suitable for Winter use.

The following chart shows the relationship of "real" viscosity to their S.A.E. assigned numbers. The relationship of gear oils to engine oils is also shown.

Multi viscosity oils work like this: Polymers are added to a light base (5W, 10W, 20W), which prevent the oil from thinning as much as it warms up. At cold temperatures the polymers are coiled up and allow the oil to flow as their low numbers indicate. As the oil warms up the polymers begin to unwind into long chains that prevent the oil from thinning as much as it normally would. The result is that at 100 degrees C the oil has thinned only as much as the higher viscosity number indicates. Another way of looking at multi-vis oils is to think of a 20W-50 as a 20 weight oil that will not thin more than a 50 weight would when hot.

Multi viscosity oils are one of the great improvements in oils, but they should be chosen wisely. Always use a multi grade with the narrowest span of viscosity that is appropriate for the temperatures you are going to encounter. In the winter base your decision on the lowest temperature you will encounter, in the summer, the highest temperature you expect. The polymers can shear and burn forming deposits that can cause ring sticking and other problems. 10W-40 and 5W-30 require a lot of polymers (synthetics excluded) to achieve that range. This has caused problems in diesel engines, but fewer polymers are better for all engines. The wide viscosity range oils, in general, are more prone to viscosity and thermal breakdown due to the high polymer content. It is the oil that lubricates, not the additives. Oils that can do their job with the fewest additives are the best.

Very few manufactures recommend 10W-40 any more, and some threaten to void warranties if it is used. It was not included in this article for that reason. 20W-50 is the same 30 point spread, but because it starts with a heavier base it requires less viscosity index improvers (polymers) to do the job. AMSOIL can formulate their 10W-30 and 15W-40 with no viscosity index improvers but uses some in the 10W-40 and 5W-30. Mobil 1 uses no viscosity improvers in their 5W-30, and I assume the new 10W-30. Follow your manufacturer's recommendations as to which weights are appropriate for your vehicle.

Viscosity Index is an empirical number indicating the rate of change in viscosity of an oil within a given temperature range. Higher numbers indicate a low change, lower numbers indicate a relatively large change. The higher the number the better. This is one major property of an oil that keeps your bearings happy. These numbers can only be compared within a viscosity range. It is not an indication of how well the oil resists thermal breakdown.

Flash point is the temperature at which an oil gives off vapors that can be ignited with a flame held over the oil. The lower the flash point the greater tendency for the oil to suffer vaporization loss at high temperatures and to burn off on hot cylinder walls and pistons. The flash point can be an indicator of the quality of the base stock used. The higher the flash point the better. 400 F is the minimum to prevent possible high consumption. Flash point is in degrees F.

Pour point is 5 degrees F above the point at which a chilled oil shows no movement at the surface for 5 seconds when inclined. This measurement is especially important for oils used in the winter. A borderline pumping temperature is given by some manufacturers. This is the temperature at which the oil will pump and maintain adequate oil pressure. This was not given by a lot of the manufacturers, but seems to be about 20 degrees F above the pour point. The lower the pour point the better. Pour point is in degrees F.

% sulfated ash is how much solid material is left when the oil burns. A high ash content will tend to form more sludge and deposits in the engine. Low ash content also seems to promote long valve life. Look for oils with a low ash content.

% zinc is the amount of zinc used as an extreme pressure, anti-wear additive. The zinc is only used when there is actual metal to metal contact in the engine. Hopefully the oil will do its job and this will rarely occur, but if it does, the zinc compounds react with the metal to prevent scuffing and wear. A level of .11% is enough to protect an automobile engine for the extended oil drain interval, under normal use. Those of you with high revving, air cooled motorcycles or turbo charged cars or bikes might want to look at the oils with the higher zinc content. More doesn't give you better protection, it gives you longer protection if the rate of metal to metal contact is abnormally high. High zinc content can lead to deposit formation and plug fouling.

The Data: Listed alphabetically --- indicates the data was not available
Brand VI Flash Pour %ash %zinc
20W-50

AMSOIL (old) 136 482 -38 <.5 ---

AMSOIL (new) 157 507 -44 --- ---

Castrol GTX 122 440 -15 .85 .12

Exxon High Performance 119 419 -13 .70 .11

Havoline Formula 3 125 465 -30 1.0 ---

Kendall GT-1 129 390 -25 1.0 .16

Pennzoil GT Perf. 120 460 -10 .9 ---

Quaker State Dlx. 155 430 -25 .9 ---

Red Line 150 503 -49 --- ---

Shell Truck Guard 130 450 -15 1.0 .15

Spectro Golden 4 174 440 -35 --- .15

Spectro Golden M.G. 174 440 -35 --- .13

Unocal 121 432 -11 .74 .12

Valvoline All Climate 125 430 -10 1.0 .11

Valvoline Turbo 140 440 -10 .99 .13

Valvoline Race 140 425 -10 1.2 .20

Valvoline Synthetic 146 465 -40 <1.5 .12
20W-40

AMSOIL 124 500 -49 --- ---

Castrol Multi-Grade 110 440 -15 .85 .12

Quaker State 121 415 -15 .9 ---
15W-50

Chevron 204 415 -18 .96 .11

Mobil 1 170 470 -55 --- ---

Mystic JT8 144 420 -20 1.7 .15

Red Line 152 503 -49 --- ---
5W-50

Castrol Syntec 180 437 -45 1.2 .10

Quaker State Synquest 173 457 -76 --- ---

Pennzoil Performax 176 --- -69 --- ---
5W-40
Havoline 170 450 -40 1.4 ---
15W-40

AMSOIL (old) 135 460 -38 <.5 ---

AMSOIL (new) 164 462 -49 --- ---

Castrol 134 415 -15 1.3 .14

Chevron Delo 400 136 421 -27 1.0 ---

Exxon XD3 --- 417 -11 .9 .14

Exxon XD3 Extra 135 399 -11 .95 .13

Kendall GT-1 135 410 -25 1.0 .16

Mystic JT8 142 440 -20 1.7 .15

Red Line 149 495 -40 --- ---

Shell Rotella w/XLA 146 410 -25 1.0 .13

Valvoline All Fleet 140 --- -10 1.0 .15

Valvoline Turbo 140 420 -10 .99 .13
10W-30

AMSOIL (old) 142 480 -70 <.5 ---

AMSOIL (new) 162 520 -76 --- ---

Castrol GTX 140 415 -33 .85 .12

Chevron Supreme 150 401 -26 .96 .11

Exxon Superflo Hi Perf 135 392 -22 .70 .11

Exxon Superflo Supreme 133 400 -31 .85 .13

Havoline Formula 3 139 430 -30 1.0 ---

Kendall GT-1 139 390 -25 1.0 .16

Mobil 1 160 450 -65 --- ---

Pennzoil PLZ Turbo 140 410 -27 1.0 ---

Quaker State 156 410 -30 .9 ---

Red Line 139 475 -40 --- ---

Shell Fire and Ice 155 410 -35 .9 .12

Shell Super 2000 155 410 -35 1.0 .13

Shell Truck Guard 155 405 -35 1.0 .15

Spectro Golden M.G. 175 405 -40 --- ---

Unocal Super 153 428 -33 .92 .12

Valvoline All Climate 130 410 -26 1.0 .11

Valvoline Turbo 135 410 -26 .99 .13

Valvoline Race 130 410 -26 1.2 .20

Valvoline Synthetic 140 450 -40 <1.5 .12


5W-30

AMSOIL (old) 168 480 -76 <.5 ---

AMSOIL (new) 186 464 -76 --- ---

Castrol GTX 156 400 -35 .80 .12

Chevron Supreme 202? 354 -46 .96 .11

Chevron Supreme Synt. 165 446 -72 1.1 .12

Exxon Superflow HP 148 392 -22 .70 .11

Havoline Formula 3 158 420 -40 1.0 ---

Mobil 1 165 445 -65 --- ---

Mystic JT8 161 390 -25 .95 .1

Quaker State 165 405 -35 .9 ---

Red Line 151 455 -49 --- ---

Shell Fire and Ice 167 405 -35 .9 .12

Unocal 151 414 -33 .81 .12

Valvoline All Climate 135 405 -40 1.0 .11

Valvoline Turbo 158 405 -40 .99 .13

Valvoline Synthetic 160 435 -40 <1.5 .12

All of the oils above meet current SG/CD ratings and all vehicle manufacture's warranty requirements in the proper viscosity. All are "good enough", but those with the better numbers are icing on the cake.

The synthetics offer the only truly significant differences, due to their superior high temperature oxidation resistance, high film strength, very low tendency to form deposits, stable viscosity base, and low temperature flow characteristics. Synthetics are superior lubricants compared to traditional petroleum oils. You will have to decide if their high cost is justified in your application.

The extended oil drain intervals given by the vehicle manufacturers (typically 7500 miles) and synthetic oil companies (up to 25,000 miles) are for what is called normal service. Normal service is defined as the engine at normal operating temperature, at highway speeds, and in a dust free environment. Stop and go, city driving, trips of less than 10 miles, or extreme heat or cold puts the oil change interval into the severe service category, which is 3000 miles for most vehicles. Synthetics can be run two to three times the mileage of petroleum oils with no problems. They do not react to combustion and combustion by-products to the extent that the dead dinosaur juice does. The longer drain intervals possible help take the bite out of the higher cost of the synthetics. If your car or bike is still under warranty you will have to stick to the recommended drain intervals. These are set for petroleum oils and the manufacturers make no official allowance for the use of synthetics.

Oil additives should not be used. The oil companies have gone to great lengths to develop an additive package that meets the vehicle's requirements. Some of these additives are synergistic, that is the effect of two additives together is greater than the effect of each acting separately. If you add anything to the oil you may upset this balance and prevent the oil from performing to specification.

The numbers above are not, by any means, all there is to determining what makes a top quality oil. The exact base stock used, the type, quality, and quantity of additives used are very important. The given data combined with the manufacturer's claims, your personal experience, and the reputation of the oil among others who use it should help you make an informed choice.

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Bavarian Technic

by Paul Dzimian

These are very exciting times for BMW, the reintroduction of all wheel drive (Xi) in the car line has been a very popular option and makes an excellent driving car with obvious advantages in the winter and some interesting possibilities as a performance enhancement the rest of the year. After all, companies like Audi have shown that all wheel drive is not just for snow. The difference between the BMW and Audi systems show some of the basic differences between the mind set of the manufactures and their engineering teams. What it all comes down to is how does it feel, in the BMW the all wheel drive distributes the power of the M 54 motor with a torque split of 38% front and 62% rear, this combined with only a very slight increase in weight (220 lbs.) gives the Xi version the same excellent feel of a rear drive BMW. Audi originally built only front wheel drive cars and their Quattro system has always left the car with a front drive bias, which is not necessarily a good thing. I spent many years building racecars for Volkswagen, (Audi's parent company) and found that a large amount of time and money was needed to reduce the ill effects of front drive cars in performance situations. I feel that a performance version of a Xi would completely outclass and out drive the Audi S (sport) models, perhaps an M car with all wheel drive someday? Please don't wake me up just yet! For those who already have an Xi, there will be many items available to improve performance from tuners such as Dinan and UUC to make your BMW a little more special.

On the subject of performance, many times significant improvements in a car are sitting right on the parts shelf, with BMW it is very common to see improvement in the breed as the model years progress and also the differences between the M cars and standard models. The devil is in the detail when doing performance modifications; many improvements can be found in changes made over the years. An example would be in the rear trailing arm bushing on previous 3 series cars, both the 325/28 and the M3 cars used the same part until the displacement of the M3 was increased to 3.2 liters. With the extensive testing done at M, it was found that this bushing was too soft for the added performance of the 3.2 motors causing undesirable changes in suspension geometry. This new part gives owners of the earlier cars the opportunity to improve their cars with a well-engineered part right off the shelf from BMW. Another "improved" part I have been using to replace the upper shock absorber mount bushing is one from the E 30 convertible. This modification has now been changed with the introduction of the E 46 series part (#33 52 6 754 096) which is better still. For any 3 series cars that are driven hard or see a race track on occasion I would also recommend adding the reinforcement plates from the Z3 (#51 71 8 413 359). These plates add strength to the rear shock mount area. In the past, I have seen the mount area develop stress cracks; these plates will help to prevent that from happening. Another very popular modification has been the X-brace (#51 71 8 410 212) originally from the M3 Lightweight along with the buffer stop (#11 81 1 095 700), the X-brace ties the front carrier mount to the rest of the chassis reducing the twist caused by high cornering loads, if you have or are considering adding an upper strut bar then you should also install the X-brace. The buffer stop is a simple rubber pad that limits the travel of the drivetrain on hard acceleration; this keeps the driveshaft at the optimum angle to transmit power to the differential. On my car, (94 E36) there has been a significant improvement with the addition of M3 suspension, chassis and brake parts along with some performance pieces from the tuners. Since the E 36 three series was introduced in the early 90's many improvements have been made only a few of which have been mentioned in this article. I am sure that many new improvements will be available for the E 46 cars as the new M3 parts come on line.

Now for a low-tech tip, I am talking real low tech. Have you ever needed to add a bit of oil to your BMW and wound up spilling some as you started to pour. Have you tried to use a funnel only to have it tip over and spill? Well worry no more I have found the perfect (close), free (sort of) funnel. I took an empty quart bottle of Mobil 1 and cut it in half, the upper half fits nicely as a funnel on every BMW motor that I have used it on and the lower half makes a nice drain cup for the oily funnel when you are done. This is the ultimate recycle for an oil bottle.

Until next time.

Paul Dzimian, Motorwerks BMW BMWTech@mn.rr.com 612-418-0608

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Bavarian Technic

by Paul Dzimian

I have spoken about this before but I am still seeing a large number of failed water pumps on the M50 series of motors. These are the six cylinder motors fitted in Three and Five series cars through most of the 90's including the M3. You can identify this motor by the black plastic intake manifold and black plastic cover over the valve cover. The motors produced from their introduction in 1991 until about the end of 1997 came fitted with a pump impeller made of a plastic/nylon material that can become brittle over time and break up or just slip on its drive shaft. This stops the flow of coolant inside the motor and causes a major overheat with no outward signs of a problem. Shops that have not seen this before will often replace a thermostat and send the car out only to have it overheat again. On these cars my recommended fix is to replace the thermostat and inspect the water pump and replace it if it has the nylon impeller. All the good replacement pumps use a metal impeller, but I have seen some aftermarket pumps still using plastic! I tell my customers to replace these pumps as a maintenance item before they fail, this can save a great deal of inconvenience and potential damage that a breakdown on the road can cause. An overheat in any modern motor can lead to very serious consequences like "blown" headgaskets and internal engine trouble such as damaged pistons and bearings. Current generation BMW motors are a hearty breed and seem to survive better then many other manufacturers in an overheat situation however there is a limit and when that is exceeded, things get real expensive, FAST.

A very common problem, especially on a motor that suffered through an overheat is that the plastic that is used in many cooling system components changes properties and becomes very brittle. The most common areas for this problem on BMW's is the upper neck of the radiator and the thermostat cover, I have seen several cars have the upper radiator neck break off while the car is being driven. In the past there have been problems with heater cores failing from too much pressure in an overheat and BMW has reissued a recall on any of the E30 Three series cars covered by this service action and letters have been sent out to the current owners with cars that still have not done the recall.

This one is easy, many late model BMW's now have dipping passenger side mirrors that let you see the ground on that side when backing up. This can be a handy feature in many circumstances. However at times it is better to have the "normal" view from your side mirror, to do this simply flip the mirror selector switch for mirror adjustment over to the passenger side mirror to defeat the dipping feature.

We will be adding monthly updates to our club newsletter; this will include a brief tech article each month. Many times these will be coming from Service Information Bulletins issued by BMW to inform the service departments of new repair techniques and fixes for both new and older BMW's. I hope that you will find this to be a useful and informative feature.

Paul Dzimian

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Winter Car Care

by John Biesecker

Many of you know me through Sterling Enterprises, my automotive cosmetic restoration and detailing business. An often-asked question from customers is: "How can I keep my car looking new, yet drive it in the winter?" My response is: "It's easy; just avoid ice, snow, sand, gravel and salt infested slush and spend the winter in San Diego!"

Maintaining a vehicle's cosmetic appearance in our winter weather is difficult without an understanding of some basics. The weather is not the real culprit when it comes to things that harm our automobile's exterior and interior surfaces. The real culprit is the State of Minnesota's DOT and its municipal counterparts. Sand, gravel and salt are useful in improving grip on snow and ice, but are very detrimental to automobile finishes and interior surfaces.

Most modern (post 1980) vehicles have excellent anti-corrosion systems in place to resist road salt and abrasion from sand and gravel. Double sided zinc alloy steel, plastic panels, high tech seam sealant and self healing finishes on lower body panels are all employed to combat rust and corrosion. If these systems are maintained by keeping the vehicle clean, and the paint and special finishes protected and/or repaired, most modern automotive surfaces can last decades without major problems. Interior surfaces, particularly carpets and floor mats need to be cleaned regularly to remove road salt, sand and gravel, which erode or abrade them.

All sounds logical enough. We need to employ a way to combat the effects of road salt and debris that can harm our automobiles, SUVs, SAVs and trucks. To paraphrase an old military acronym KISS (keep it simple stupid) lets use KICS (Keep it Clean Smarty). There is no better way to protect your automotive investment than to keep it clean! During the winter, regular washing removes salt deposits and sand and gravel, which build up in crevices and in fender wells. By keeping the vehicle clean we can also keep its exterior surfaces waxed which does not directly prevent corrosion but protects the paint systems from abrasion caused by road debris. By protecting the paint systems we prevent or reduce the effects of pitting, nicks and scrapes which allow corrosion to begin working on the underlying metals. By removing sand, gravel and road salt from interior surfaces we prevent the detrimental effects of those contaminants on carpets and floor mats.

How should we accomplish this KICS method of maintaining our vehicle's cosmetic appearance? The best way to clean a vehicle is to hand wash the exterior surfaces and vacuum /shampoo interior surfaces of the vehicle every week! So just pull your vehicle into your heated garage with the floor drain, get out your hose, crank up the radio and.. "Whoa!" You say. " It's -10 degrees outside, I have no access to a heated garage!" You've got a problem!

Not really, the next best system to hand washing at home is to take your vehicle to a do-it-yourself car wash. Take your own bucket and car wash soap to the self-service bay and use only the Rinse Cycle to fill the soap bucket and wet the car. (You do only use car wash soap don't you? Dish soap is made to remove grease and it will also remove wax! Self serve and automated car washes use strong soaps that are made to remove all kinds of dirt and grime as well as wax! Use your own car wash soap.) Even when it's very cold outside, you can do a fine job in a self-service bay particularly if you go early in the day or late at night. There will be fewer people, the doors will not be opened very often and you won't be rushed. I've never had a problem using this method. Plan on spending about ½ hour and about $3.50 - $5.00 in change. Necessary materials are: 5 gallon bucket (smaller will work, but won't let dirt and grit fall to bottom of bucket away from your wash mitt), cotton/wool wash mitt (don't use rags, they don't hold enough soap/water and won't release dirt as well as mitts), car wash soap, wheel brush/sponge, 100% cotton towels for drying (at least two bath size towels). Optional items would include: squeegee, foam type window cleaner, tire dressing, trim dressing and detail brushes for the interior.

Washing a vehicle is easy, just slop soap and water on and rinse off, then dry. Yeah, that might do it. However, similar instructions for planting flowers might read: dig hole, put in seeds/bulbs, water, then let grow. We might get lucky in both cases and end up with a clean car that's unscratched and tulips that actually bloom. Here's the process for doing the least harm to your vehicle when washing it at a self-serve car wash:

Rinse entire vehicle, start at top and work down (Use high pressure sparingly on wheels and lower panels, make sure that all heavy concentrations of sand/gravel are knocked off, pay close attention to body seams and areas around wheels wells)

Using your bucket and car wash soap, soak mitt completely and wash car from top down, do not do wheels at this time. Do sections at a time, then rinse. Example: wash top, rear deck, windows and hood; then rinse. Rinse your mitt at this time also. Then do one side, rinse car and mitt; then complete other side. This method helps keep soapy dirt from drying on car and cleaning the mitt after each section minimizes the chance for grit, sand and gravel to get trapped in mitt.

About this time you realize that for this system to work, you are not using the spray wand all the time yet you are paying for it to be on. That's why it takes $3.50 to $5.00 to clean your car in this fashion, but it's still cheaper than an automated wash that grinds dirt, gravel and salt slurry into your paint. Oh, and if your car follows that 1989 Olds with the clapped out fenders, add rusted metal into the mix that grinds into your car.

When car is completely washed and rinsed, use the wheel brush/sponge to clean wheels and tires then rinse. (It's best to do one wheel and tire at a time rather than all at once just to be sure to get grit out of brush/sponge and to let the high pressure wand work it's magic).

Dry the car. I didn't like to use squeegees in the past, however the new soft clear plastic type seem to do no harm and really reduce the amount of time and towels it takes to dry a car. Use them if you like. Dry car from top down using back and forth strokes. (If by some bad luck you get a small bit of grit in the towel, the straight line scratch that results is a lot easier to buff out than the spiral type resulting from drying in a circular method.) Use only 100 % cotton towels with little or no decoration!! Towels with synthetic materials like nylon or rayon will scratch paint; the threads used in decoration and edges are usually synthetic yarns. Keep them away from your paint!

When exterior is dry, wipe out trunk jamb, doorjambs and hood jambs. Be alert for grit in these areas! If you have not kept these areas clean, wash them out when you wash the car (It can be done without water getting into the interior. You can figure it out.) Even if you wash these areas often, still be on the alert for grit. You must clean and dry these areas; otherwise doors and panels can freeze shut or damage rubber seals. Dirty doorjambs also keep dry cleaners very wealthy during the winter.

Stand back and admire your work. It's somewhere in the fog! If the service bay is so humid that it's difficult to dry the car simply open a door slightly. The cold dry Minnesota air will quickly get rid of the fog and allow you to finish drying.

Now the part that requires creativity: Using the vacuum cleaners located outside in the frigid air requires one to work fast or simply to go home and use a shop vac in your own garage out of the wind. In either case, spend most of your effort to get dirt and salt out of the foot wells and floor mats. If the carpets/mats are really dirty and salt stained, you may have to wait for a warmer day to vacuum and shampoo completely. Mats can be taken in the house and cleaned in the basement or the bathtub depending on how good your relationship is with your spouse/partner/lover/significant other. Please clean up completely!

If all this sounds like too much work (remember we are talking only ½ hour) then take your car to the automated car wash and let them have at it. Don't use the cheapo brush type washes found at service stations; they do real damage to paint surfaces. Touchless type washes don't clean very well and use very high pressure, which can damage paint. The best automatic washes use the felt type material that simulates hand washing and they use lots of water. Then they use cotton towels to finish drying the car.

However, even the very, very best automated car wash cannot do the type job you can using the KICS method. The very, very best automated car wash cannot guarantee that there are not grit or rust particles in their wash brushes/batts or in their drying towels. They cannot guarantee that their people care as much about your car as you do! Of course if their people do care more about your car than you do then you won't be reading this anyway!

The other option is to let a professional detailer do the work for you. One method that some of our customers use is to use the best-automated car wash they can find (Unfortunately, this requires trial and error type research; however the Paradise washes look good.) for weekly cleaning. They then bring the car to us for a quarterly or semi-annual detail to remove swirl marks and interior cleaning. As an example: one customer has two SUVs driven year round and an M5; the SUVs get weekly automated car washes then brought to us three (3) times per year for complete details. The M5 gets two details per year, only hand washed in between details and stored in the winter!

However you choose to accomplish the goal, remember KICS (Keep it Clean Smarty).

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Bavarian Technic

by Paul Dzimian

Redlines, Red lights and things that go bump in the night.

This technical article was not going to be on this subject, but it has become clear to me that it is what I need to write about.

Over the past several years I have noticed that a very large percentage of the engine failures in BMW's have been due too mechanical over revs. The cause of this is from incorrect gear selection on downshifts. This problem seems most prevalent in, though certainly not confined to, the M3.

The advent of modern engine management systems gave manufacturers the added bonus of incorporating an (RPM) limiter into their systems. This was done to prevent engine damage caused by running an engine at too high a rpm under power (accelerating). Limiting is accomplished by shutting down the ignition or fuel systems as needed to keep the engine speed below the design tolerance of the motor. Rev-limiters are very effective in preventing damage in this manner with the newer systems making a very smooth transition into limiting that simply feels like you have run out of power.

The problem is on the other side of the equation. This limiting cannot help on downshifts. In this situation the engine is not being powered by the engine management system. Instead it is being spun up in reverse order through the rear wheels back through the drive train. An incorrect downshift, for example 5th to second instead of fourth, will generate an incredible shock through the drive train and engine. This will cause the engine to spin up, potentially to twice its redline in the time it takes for the clutch to engage. The resulting impact can destroy the motor and could cause major damage the transmission and drive line as well.

The root cause of these engine failures has been debated over the years, with theories ranging from problems with valve spring retainers to valve timing problems with the Vanos. All of these must be discounted by the fact that in almost every case, when the information from the engine computer is downloaded the readout for highest rpm is way higher than the redline for the motor.

An Ounce of Prevention

The single most important thing to prevent this from happening is to understand some driving technique and to take the time to think. Typically these failures have come when someone finds themselves driving past their limits either in racing or a driving situation on the highway. Instead of a correct downshift the wrong gear is selected and next thing they know the red lights in the dash are on and they have a big problem. Think about your shifts, never, ever use the transmission to slow down a car, that is what brakes are for. For performance driving learn to match rpm's to the downshift to keep on the power instead of letting the engine be dragged up to speed by the clutch engaging.

From the mechanical side of things, I find that the design for attaching the shift console to the transmission causes a certain amount of vagueness to the shifting. BMW uses an oval shaped soft rubber bushing that I believe allows the tower to move around too much. A Delrin nylon bushing set is available in the after-market that helps make shifting more precise. Any worn parts in the shift mechanism should be replaced to avoid free-play in the shifter. Common wear points on all BMW shifters are the front shift coupler at the transmission, the yellow shims on the shift rod and the nylon shifter pivot cup. Also as anyone that has ever talked about shifters with me knows, I am a big believer in short throw shifters. A properly engineered short shifter will feel sportier and at the same time allows shifts to be more precise. My favorite short shifter (yes I sell them) moves the pivot point in the shift console to keep the shift rod running at the correct angle to the transmission, this keeps the shifts very smooth yet reduces the throw by nearly 50%! Visit UUC at www.shortshifter.com for a full description of their exceptional products, or give me a call if you need more information. By no means will any of this help if the wrong gear is selected, however it will give you a better feel for the shifter and a more accurate shift gate.

Update

As of the June issue of the Roundel I am officially a Technical Service Advisor for the national BMW CCA. This is something that I have been working toward for over a year. I will continue to serve as tech advisor for our chapter; one of the added benefits of this is that I will be available for calls from 6 till 9 in the evening at 612-934-6672. It is my hope to eventually add a web site with BMW technical FAQ's.

Tools

Over the years the best tools that I have ever bought have been books. Many times these have been technical service manuals for the cars that I have chosen to make my living out of fixing. I have found that the correct information can make the difference between a easy fix and a nightmare. In recent years BMW has been less then forthcoming with information on its cars first by stopping production on paper manuals and only issuing large format microfiche, then fazing out the microfiche. Professional technicians are able to get the information they need through subscription services such as Alldata or Mitchell on demand, however this leaves the do-it-yourselfer out in the cold. To the rescue for 92-98 (E36) 3 series owners is the new service manual from Bentley Publishers. Although the information is abridged from the "factory" manual this is an excellent quality manual that will cover any task you are likely to attempt. Currently Bentley offers manuals for 84-90 E30 3 Series, 82-88 E28 5 Series, 89-95 5 Series, and the 96-98 Z3. I highly recommend them.

Paul Dzimian

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Bavarian Technic

by Paul Dzimian

Upgrades and improvements

As spring arrives in Minnesota, we all start to think about the things in our lives that need improvement. Being a "car guy" means one of the first things I start thinking about improving is my car. Judging by the number of phone calls I have received so far this year, I am not alone. In this issue of the Technic, let's get into some of the fun stuff. We will start with some basics; more will follow in the next issue.

Brakes

When we think those performance improvements on cars the first thing that comes to mind are usually not brakes. Excellent, consistent braking is one of the most important qualities of any high performance car.

1. A significant upgrade in braking performance can be gained by changing from a stock brake and in the pad to a more aggressive compound such as metal masters or performance friction. It is important to remember that the job of brakes is to reduce the kinetic energy (speed) of the car through friction. This friction causes a great deal of heat to build in the brakes, in particular the brake and rotors and brake fluid.

2. Rotors are subjected to a great deal of heat and ware in just normal driving situations, when subjected to the rigors of "performance" driving the added stress load can quickly destroy them. To combat this, the car designers and engineers have paid close attention to airflow to the brakes to allow for cooling. Other improvements in brake rotors have come through internal venting, cross drilling and gas slotting the rotor surface. One of the most recent innovations in rotors is the use of cryogenic treatment of the rotor (Frozen Rotors). This has been very effective in reducing the tendency of rotors to warp or crack when pushed to their limits.

3. No matter what, brakes will get hot. Very hot. That heat transfers into the brake fluid where in extreme cases it can cause the fluid to boil. As brake fluid ages it attracts moisture. This reduces the boiling point of the fluid buy a significant amount. Premium brake fluids such as Castrol LMA or ATE Super Blue have a higher boiling point and fewer tendencies to pick up moisture.

4. Brake hoses have the job of transmitting the hydraulic pressure of the brake system to the caliper. Stock brake hoses tend to balloon out under this incredibly high pressure increasing the pedal travel and reducing the "feel" of the brakes. Replacing the rubber flex hoses with special nylon hoses that are wrapped in woven layers of Kevlar and stainless steel will improve the feel of the brake pedal.

Tips for doing brake work.

5. Follow the brake in procedure for new brake pads. This is a critical process to get the most out of your new brakes.

6. The mounting surface for brake rotors must be clean and flat. Any dirt will cause rotor run out and prevent proper heat transfer out of the rotor.

7. When pushing caliper pistons in for new pads, loosen the bleeder screw to expel the old fluid from the caliper. Never push the old, dirty fluid back through the system and into the ABS unit or master cylinder. Grief can result.

8. If you will have the hydraulic system open for any amount of time, wedge the brake pedal down just a couple of inches. This will close off the port to the reservoir preventing all the brake fluid from draining out.

9. Always use fresh brake fluid from a sealed container to avoid contaminating the brake hydraulics.

10. Never use silicon-based brake fluid. These fluids are incompatible with conventional brake fluid.

11. When dealing with brake lines patience is a virtue, avoid rounding off line nuts when loosening. Take care to avoid cross threading on reassembly.

12. Always torque wheels to specification after you first snug them all down. This will prevent the wheel from rocking out as the first wheel bolt is tightened to torque.

13. When you're done working on your brakes, before you attempt to move the car PUMP UP THE PEDAL! You would not be the first one to drive through a garage door trying to pump up the pedal.

Special Caution Regarding Ball joints on all 3 series cars.

A recent report from BMWCCC regarding track incidents indicates a high failure rate on ball joints in E30 and E36 cars. This has been most pronounced in cars in cars with high mileage and/or the use of sticky track tires. I will be paying very close attention to ball joints in our track inspections to avoid problems at our events.

At your service

Paul Dzimian

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Bavarian Technic

by Paul Dzimian

As some of you know, I am a member of The Service Technicians Society (STS). This is a professional organization dedicated to advancing the skills, education and professionalism of service technicians to support excellence in the automotive industry. One of the best things about being a member of STS is that I have access to many of the interesting engineering papers published through the Society of Automotive Engineers (SAE). I can read about such fascinating topics as "Chemical Aspects of theDynamic Performance of a Three-Way Catalyst." Fun huh?

Every once in a while there is something interesting that is useful for real people. In a recent paper, research has shown that up to 90% of all accidents, deaths and injuries can be prevented by improving the visual aspects of driving. The range of this study involved everything from lighting to changing tire coloring. Many of the recommendations are intended for highway departments and car design teams but some things just make sense to do something about. For example, as a nation we do 28% of our driving at night but 55% of all traffic fatalities happen in the dark! I do not have numbers for BMW's in particular but I am sure that they will be very close on that statistic because one area that is controlled by legislation instead of engineering is headlights. In the United States the headlights used in cars are controlled by the Federal Motor Vehicle Safety Standard No.108 which, until very recently, has locked in place many of the design features of headlights since the inception of sealed beam headlights. Much development has gone on since. In Europe headlight technology has been improving as rapidly as all other aspects of the automobile. Here is how the headlights compare.

The Sealed Beam

Through much of the 80's most BMW's were equipped with sealed beam head lights in a four light set. The outer two lights are low beam and the inner two are high beam. Sealed beam headlight technology is limited due to DOT regulations and the economics of a light that is thrown away when the bulb fails.

Tungsten Sealed Beam

The original sealed beam, it produced a dull orange light. About the only excuse for using these lights is if you have a 2002 or older model BMW that you are NEVER driving at night. These lights had a very unfocussed beam pattern and low light output. Their use should be limited to spot-on accurate restorations of show cars; not for anything that is driven.

Halogen Sealed Beam

I am old enough to remember how good these lights seemed when they first became available around 1970. They were so much brighter and longer lasting then the earlier tungsten bulbs that had been available before. These are the basic headlights in many of the BMW's over the years. These lights are quite inexpensive so the design of the lens is kept to the minimum requirements needed to keep production costs down.

Replaceable Bulb Headlights

These lights have a separate bulb and lens assembly allowing for much improved optics over a throw-away design. There are DOT spec and European code lights available. For the US market lights are built with a large percentage of light scatter to meet DOT requirements. In Europe the standards call for a much sharper cutoff at the top of the light pattern to prevent glare for oncoming traffic. This also greatly improves the amount of usable light on the road.

E-Code Replacement Lights

If your car came with sealed beam lights you do not have to stay in the dark. There is an option in euro-spec headlights that are available. These lights have a much better light pattern and replaceable bulbs . The light is far less likely to cause glare due to the improved lens design and makes a major improvement in driving at night. These lights are available for the 5", 7" and some of the rectangular lights used in some domestic cars (like my Ford van). I have installed these in every car I have owned that came with sealed beams.

Ellipsoid "DE"

BMW was the first car company to offer these headlights in 1986 for the low beam lights on the 7-series cars followed by the 3 and 5-series cars the following year. Ellipsoids are a big improvement in light design in that they work like a projector, sending a very focused beam of light. Even in the DOT approved version it is an excellent headlight though the E-code lights are even better. You can tell an ellipsoid light by the inner lens that looks like a magnifying glass. The one drawback is the relatively high price for the light assemblies.

Aerodynamic Light housings

Late model BMW's have gone to "aero" headlights on all cars to reduce wind resistance on the front of the car and allow more streamlined styling. Many of the E36 3-series cars are starting to show damage to the outer plastic cover of the headlights, these covers are not replaceable separately. On my car, I replaced the light assemblies with assemblies containing the E-code lights. These lights have the DE low beams and a hardened glass outer cover with the superior euro light pattern. With the standard 55w bulbs the usable light is about doubled from the stock light. This has proven to be one of the most useful upgrades that I have ever done.

High Intensity Discharge (HID) "Xenon"

Once again BMW was the first car company to offer this radical departure from conventional lighting. In 93 they began using Xenon lights as an option in the 7 and 8-series cars. This lighting system is a completely different way to produce light. These lights are similar to the lamps that are used for stadiums. The big difference is that headlights must be instant on lighting. To accomplish this, a ballast transformer steps up the voltage to 25000 volts and an ignition system starts the arc. These are very involved systems with safety measures built in to disable the system in case of a crash to prevent danger from the high voltage system. These lights are designed to last the service life of the car without replacing the bulb. You can tell HID lights by the blue color and amount of light. The blue in the light is the after effect of filtering out the large amount of ultraviolet produced, as the filtering is improved and this blue is eliminated these lights will be even better. Until this year Xenon lights were a fairly rare sight however it seams as though every new car you see has them now. Anyone considering ordering a new car should consider getting them as they are quite reasonably priced in a new car deal, and extremely expensive to retrofit at a later date. These new lights have caused the DOT to change its policy regarding headlights. The same lights are now EC and DOT approved.

Paul Dzimian

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Bavarian Technic Top

by Paul Dzimian

Coils & Spark Plugs / Ignition systems

In my time as a professional mechanic I have seen ignition systems grow and refine. From a points-fired, mechanically driven distributor with centrifugal spark advance to a computer controlled individual coil per cylinder system that can alter the timing on a spark by spark basis. The advances in ignition systems have lead us from a ignition in a 2002 that Henry Ford would understand to something Bill Gates could, only far more reliable then most of Bill's offerings.

Coils

Ignition coils are essentially a transformer; they take the low voltage of the cars' electrical system (13.5v) and step it up to the 20-50 thousand volts (KV) needed by modern engines. The newer BMW's use separate coils for each cylinder that are triggered by the DME, engine management computer. This has presented a new problem, if one of the coils should fail it can cause an overload in the drive capacitor in the DME to fail requiring replacement of the computer.

Spark Plugs

I am a big fan of Bosch spark plugs. This comes from years of personal experience with many different brands and anecdotal evidence from other mechanics. The exception being the late model engines (M50-52, M42) where the NGK plugs seem to work as well. BMW uses both Bosch and NGK as suppliers for spark plugs.

Never, ever use those silly plugs with the split negative electrode. They are junk! They do not work, when mechanics see them in your motor they laugh or get angry or both. These are possibly the most poorly made and designed, mass marketed plugs that I have ever seen. They have no electroplated coating to keep them from corroding or seizing, no ribbing on the ceramic insulator to help prevent shorting to ground and the split electrode is very crudely made. Someone stop me! While I am at it, avoid the Bosch platinum plugs. The ones in the silver - gray boxes that they use in all the commercials. They have a shrouded center electrode that is very prone to fouling and have never proven any advantage over the conventional plug.

In many six cylinder BMW applications a silver electrode spark plug is called for and they are outstanding though somewhat expensive. These plugs give excellent performance, and a long service life.

Up until the early 90's most BMW motors used a spark plug with a 14mm thread single electrode and a body with a 13/16 hex. The exception being the Motorsport engines, which use a 12-mm thread and a 16mm hex that requires a special thin wall socket to fit down the tube in the valve cover. Some of the replacement plugs for the M motors (s14, s38) come with a 5/8 hex. The new generation motors (M50 & M42) are using a 14mm thread with a 5/8 hex.

Paul Dzimian

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