toofast928

I set the cams 2 degrees adv on my 4.5l USA engine. Felt more bottom end power up to 3000 RPM.
Its more important that both cams be set to the same setting. That the left bank and right bank are not fighting each other. Think about Roger's Gates Racing T Belt so the cam settings don't change with belt stretching.

joejoe

I have an '81 that had the distributor advanced 1 tooth on the shaft and the advance was cranked all the way advanced also. I did not know much of these cars (still don't) but the car ran like a raped ape. It was extremely quick off the line and would outpace the '86.5 I have (up to about 70-80 mph) The car passed calif smog this way, twice!. The third time it barely failed, and digging into it found the advance pot inside the distributor had actually fallen off. It functioned correctly, but was not connected to advance/retard timing.

Performance wise I really liked the car, economy wise it was a disaster. MPG of 10-11 was the best I ever achieved. This was regardless of how driven.. hard or normal, no difference. Pulled dist. re-stabbed to correct position, retimed, and car has been good since (8/9 years)

The Fixer

So you used the 2 degree advance key from 928MS? I have a US 83S, do you think i should try the advance key?
Very good advice on the racing belt, i may get one. I have been concerned that setting the tension would be tricky (another thread, subject beaten)
IIRC upon checking the TB I noticed at TDC one cam was slightly off the mark.


I've read that these 16V motors really respond to advancing the distributor (Think it was Greg Brown)

My distributor has never been moved from new (serviced by the same people all those years) But I will advance mine slightly once everything else is done.

123quattro

Do the timing now. It takes 5 minutes and is free.

toofast928

Matthew,
If I remember right the driver's side cam is already slightly advance as by the belts pitch. So your really just advancing the pass. side camshaft, think I did 1.4 degree or so. Just keep in mind that the driver's side camshaft will have a spark timing effect on the passenger side bank. So if you set the cams 0 or advance its important they both have the same camshaft degree setting.

As fas as advancing ignition timing. If your factory spec is 23 BTDC. You can advance as much as 4 degrees.

Strosek Ultra

I have never tried advancing the ignition timing on a 928 but I have two older BMW project cars from the late 70s and one from the mid 80s. All cars have responded very well advancing the ignition by about five degrees. The newer car is burning E85 and the ignition had to be advanced to 43 BTDC in order to get the power up.
Åke

Ad0911

When I bought my car, it drove really well. Good starting, good pulling power, good top end power. However, when I dismantled the engine for a top end overhaul (due to blown headgasket) I noticed that I could not synchronize the markings on the belt pulley drive at the balancer and both camshafts. The camshafts could not be turned in such a way that the markings were lined up both at the same time. They were out of sequence approx 30 degr (yes 30!) furthermore, the balncer with the degree scale was mounted the wrong way around so the timing could not be right. This must have resulted in mistimed camshafts, or in other words, drastically retarded or advanced camshaft, either left or right. It was a damn miracle how that engine could run so well! Thanks for nothing PO!