compression and leak-down #s - need advice ASAP
 

Mechanic just finished the PPI on this car. It is an 87 Coupe w/107K miles. The compression and leakdown #s are as follows.

170, 8%
170, 10%
165, 10%
175, 10%
175, 8%
170, 8%

BA's book says 130 - 170 and around 3 - 5%. So, I'm a little worried about the leakdown numbers. What do you think?

I just bought an '87 with 84k. The first leak down and compression was low. The owner paid to have a valve adjustment and afterward everything was in line:

Compression

Before 180 180 185 190 150 150
After 185 190 190 190 180 190

Leakdown

Only have the after numbers
1% 0% 0% 0% 5% 5%

Don't know if this helps but I just wanted to give you a frame of reference.

Leak down numbers can be tricky. Carbon can really play factor as it can prevent a valve from closing completely.

IMHO, these items are worth checking also

Pull the valve covers, see if the head studs are OK.
Check if the motor starts and runs fine OK
Look for oil leaks
Ask for maint records
Talk to the current wrench if possible
Look for body damage

With 107K, the motor may be OK. The tranny may be in need of some attention due to normal wear (Syncro stuff)

from the way the carreras beat out the valve seats from having worn guides, i think those leakdown numbers are reasonably good at 107K. personally, i've never seen 0% leakdown on anything. quite odd.

'personally, i've never seen 0% leakdown on anything. quite odd.'

I have no prior experience with a test like this and after reading your post I understand your point. This test was done by a reputable Porsche shop. There is a lot on the line for a shop to fabricate these numbers. He could just have easily shown 2-5% and nothing would have changed.

If 0% is in fact not atainable, he took a huge risk. Quite odd.....

Thanks for the advice fellas. Everything else on the car checked out so I gave the seller an offer today. Will let you know and post pix if seller accepts.