Leak Down Questions
 

I just finished putting a 993 engine back together after a total rebuild. Before I put the engine back in the car I did a leakdown test with the following results. The test was done cold. All the rings are new. All cylinders had air blowing past the rings (breather hose noise). Could this be because the rings have not had a chance to seal or because of cracked/broken rings? Test done at 100 PSI.

Cyl 1 6%

Cly 6 3%

Cly 2 8%

Cyl 4 12%

Cyl 3 11%

Cyl 5 3%

How far does your car run down the street cold, never having the engine run?
All you can use these numbers for is reference against a running hot engine.
Bruce

I think if you had a broken ring, you'd have more leakage than that. It will be something to compare with after you break in the engine.

-Andy

Just wanted to run this past the experts. 11 and 12 percent gave me the willies. My thinking was if I need to fix something I had better do it now while the engine is out. For some reason I was expecting more uniform numbers. The experience continues....