lucycan

I was told by a shop that if I am doing a full leakdown (for a PPI) that there is really no reason to do a compression test as well.

Sound right?

Robin 993DX

The way a leakdown supplements the compression test is that you do a compression test first and if there is a noticeable low number you use the leak down test to find out if it is from the rings or valves.

lucycan

So if I were obsessive on the PPI I should just go ahead and do a full leakdown?

MarkD

Leakdown #s are critical on these engines, no doubt about it
Leakdown gives a much better indication of engine health.

Robin 993DX

No, you should do a compression test on a fully warmed up engine. The key point is comparison from cylinder to cylinder not how high the compression is.

Steve Weiner-Rennsport Systems

Totally concur,...

Robin 993DX

Steve, thanks for jumping in on this one, sounds like I need some education here.

I was always under the impression that a leak down may not correct reflect cylinder to cylinder comparison?

Steve Weiner-Rennsport Systems

Hey Robin:

How are ya doing?????

Leakdown testing is FAR more indicative of engine health and an opportunity to pinpoint any source of compression loss.

Compression test results are affected by cam profiles and timing and I don't normally do them anymore.

lucycan

Thanks guys!