Philes' Forum by Vic Lucariello

Hello Bimmerphiles! This month I return to my normal format [I promise, no tirades on dirty brake fluid]. I answered a few interesting e-mail questions, some of which I think you will be interested in. But first…

The current issue of Automotive Engineering [The journal of the Society of Automotive Engineers] has an interesting article describing BMW's new Diesel V-8 which powers the European 740d. This trick 3.9 l motor, which produces 245 HP @ 4000 RPM and 413 [!] lb-ft of torque at 1750 – 2500 RPM, is said to be the most powerful diesel engine in a production passenger car. [For comparison, the larger, 5.0l normally-aspirated gasoline V-8 in my Ford pickup produces only 200 HP.]

Some of the features of the new motor are direct, rail-style fuel injection, twin turbochargers, and four-valve combustion chambers. Although diesels have been turbocharged for years, four-valve heads and direct injection are relatively new developments. Direct injection means that the fuel is injected directly into the combustion chamber as opposed to the traditional pre-chamber. Direct injection provides benefits in economy, power, and emissions.

For those of you not familiar with diesels, they are technically known as Compression Ignition [CI] engines because they use the heat generated by their compression stroke to ignite the fuel, which is injected when the piston nears the top of its travel. This requires a compression ratio considerably higher than a Spark Ignition [SI] engine [the technical name for a gasoline engine], which of course uses a spark plug to ignite the fuel/air mixture. The SAE article did not state the compression ratio of the new diesel, but I bet it is more than 15:1. Modern normally-aspirated high-performance SI engines run about 10:1 compression.

Because of the higher compression ratio and unthrottled air intake [on a CI engine, load is controlled by 'throttling' the fuel, not the air like in a SI engine], a diesel should provide better fuel economy than a SI engine of similar power output. This is why CI engines are popular in Europe. The traditional disadvantages of diesels are fuel odor, noise, exhaust soot, cold weather starting, and weight.

Now if we can only convince BMW NA to donate one of these new diesels for the NJ Chapter to evaluate, I know of a Ford pickup we can use for the test program!

Bimmerphile Lou Gubitosi asked the following:

The dealer told me that my black 97 328 does NOT have clear coat. I am preparing to repair some chips and plan to fill the chips with lacquer paint mixed to match, sand the paint to a smooth finish with 1000 grit and 1200 grit then polish. I do plan to avoid the surrounding area, but I will need to be more careful if there is clear coat. Do you know?

My Response:

Lou, I do not think that the black is clear-coated. For years, BMW has used clear coat on the metallic finishes. It is easy to tell. Put some rubbing compound on a cloth and rub out a hidden spot with your finger. If the cloth has black pigment on it after rubbing, you have no clear coat.

If you haven't yet tried the technique you describe, I recommend you practice on a hidden spot anyway. It is easier said than done. Also, I think you should use the BMW touch-up paint intended for your particular car. Good Luck!

The Eastwood Company makes some trick little finger-operated buffers and sanders intended for just what you intend to do, so check them out.

Bimmerphile Jeff White had an interesting problem changing the front control arms on his E30 325ix. The ix uses a sickle-shaped control arm similar to the other E30s, so this item applies to all the E30 cars.

The inner ball joint stud in the control arm attaches to the front subframe. Normally the securing locknut, while not particularly accessible, is easy to remove from inside the engine compartment. In Jeff's case, however, when he tried to loosen the locknut, the whole ball joint stud was turning in the subframe and therefore the nut would not come off.

I suggested to Jeff that he place a bottle jack under the ball joint and press the ball joint stud more firmly into its socket in the subframe. This trick results in the stud being harder to turn in the subframe as well as slightly decreasing the tension on the stud/nut combination. In addition, a bit of heat applied to the locknut will melt its Nylon insert to further facilitate removal.

In Jeff's case, neither trick was of any help and he ended up having to cut off the locknut with a Dremel tool! B U M M E R !

I also suggested to Jeff that he check the tapered socket in the subframe to insure that it was not enlarged or otherwise deformed. Also, it is important to properly torque all fasteners, especially these. As I have mentioned previously, too much or too little tightening torque on a ball joint stud can cause the stud to fail!

Well, that's all for this time, Bimmerphiles. In an upcoming column, I will have Lime Rock Hot Dog Alexei Tsekoun's account of how our friends at Hunterdon BMW resolved a warranty issue with the clutch on his 318 ti. Also, I am putting together a column [with pitchers, Ross!] about how Big Al's M3 twice lost its alternator belt and coolant at our September Lime Rock Driver School. [As if the track wasn't wet enough that day!] I had wanted Big Al himself to write the story, but he says he lost his crayon.

Anyone wishing to contribute to Philes' Forum should contact me via the info on the masthead. I'm interested in tech tips, repair/maintenance questions and/or tips, dealer horror stories, product evaluations, etc. Please call before 8 PM, and if you leave a message, PLEASE INCLUDE A PHONE NUMBER WHERE I CAN REACH YOU DURING THE DAY ON WEEKDAYS. Also, please be patient, I try to return every phone call, but it sometimes takes a while. If you don't hear back from me within a few days, please call again. The best way to contact me is via e-mail.

Copyright 1999 - V.M. Lucariello, PE