911 SC Smoking
 

Ho Guys,
I have done a top end rebuild on a clients 911 SC, including rings, hone cylinders and head work.

The problem is that the car smokes when ideling for a while. The smoke is white and clearly visible from the exhaust. If the engine is reved after ideling for a while, the smoke pours out.

I have since replaced the rings - more than once, had the cylinder checked - still OK, and replaced the valve stem seals for good measure.

We have since check all breather hoses, scavenge circuit for blockage, the fuel distributor etc.

Just to point out, we do about one engine every month or so, and have never had a problem like this. My development race motor, that has done in excess of 200 dyno pulls to rev limit, has never smoked, and neither has any of my other motors.

This one seems to have me beat.

Any ideas, good or bad will be welcomed.

Hi,

The VERY first thing to do at this juncture is a leakdown test to see if the rings are seating or not.

I've had mixed success honing and re-ringing used cylinders over the years so I rarely do that anymore. Now, I never hone them; they simply get deglazed with Scotchbrite pads and then subjected to a VERY thoroughly cleaning.

If the numbers show the rings are not seating after a few hundred miles of on-off throttle driving, its time to take it apart and perform some forensics to see what is going on.