In Reply to: S-14 motor is a iron block not Aluminum posted by Angus on September 30, 2000 at 13:46:10:
The E30 M3 is gonna burn oil.
The S14 has an aluminum cylinder block with forged aluminum pistons. When the engine is cold, the clearances between the pistons and cylinder walls are larger than your basic iron-block motor. As the engine warms up, these clearances close up, but as it's warming up, it's probably burning a little oil.
WARMING UP THE MOTOR IS VERY IMPORTANT. The owners manual states that engine revs should not exceed 4000 rpm until the oil temp is at least 125 degrees. My warm-up ritual took about 5 miles, and about as many minutes, never exceeding 2500, from the time I started the car. As long as the thing was warmed up properly, my oil consumption was about 1 qt every 3000 miles --- about every oil change. I didn't have any dirt or oil around the tail-pipe. And absolutely no smoke. My wife never got the routine right: whenever she drove the car, I'd check the oil the next day; added a half quart every time.
(After the car was warmed up, I usually ran it between 2500 and 4000, with frequent bursts above 6000; I probably hit the limiter at least once a day, sometimes more. Apart from a tensioner, the only major repair I had on the car in 5 years was the rear brakes . . . after 85k miles.)
I used Valvoline 20w/50 racing oil; with 15w/50 Mobile 1, oil consumption almost doubled.
When I first got the car, the oil consumption really surprised me. My mechanic said factory oil consumption figures allowed up to a quart per 750 miles, so I should relax.
Anyway, I hope this helps. Good luck.