PPI Compression and LeakDown Results - '79 930
 

I had a PPI done on a 1979 930 I'm considering buying which shows 21K miles.

Compression came back at 135 for all six cylinders and 110/110 for all six.

I thought results like this were impossible. When I asked the mechanic, he said it was uncommon, but that he does see it occasionally.

Any thoughts?

Thanks!!!

also... I searched for what the numbers should be and came back with nada...

Well 135 in all 6 cylinders for compression is good, but I don't understand the 110/110 for a leakdown figure. Normally it is expressed in percentages. Anything less than 5% leakdown is good. Is he trying to say the leakdown is 0%? If so, then I question the accuracy of the test. Every cylinder will have some leakdown as no cylinder is air tight!

The "110 over 110" is what I was told over the phone. I THINK he was telling me 0%. I'll find out for sure this afternoon when I go back to pick up the report.

Thanks.

Even an engine that had vitually no miles will show some leak. I agree with Kurt that it should be between 1 and 5%. Don't be afraid to ask for a re-test!!!
Good luck,

Hey skip- If you are looking in Dallas, check out this one:
http://cgi.ebay.com/ebaymotors/ws/eBayISAPI.dll?ViewItem&rd=1&item=2482753269&catego ry=6433

Also I've done my own leak down tests, and with 100 PSI on a 3.2L engine I got close to 0% leakdown, (less than 1 psi drop). I was surprised. This was with an engine that clamed to have only 15K miles on it.

Yup, looked at that car a month ago... Looks like they are having a tough time selling. Thanks for the head-up though...

When I bought my 930 motor, I did a leakdown. I got 1% to 2.5%. Most were 1.5%
Dean

I had the engine rebuilt on my 89 930 when I got it (broken rings). I did a break-in drive of about 1000 miles up and down hills, full throttle then engine braking, etc. When I took it in for the 1500 mile service, I had the mechanic do a leakdown. He said he got 0% leakdown on all 6 cylinders (the needle just moved off the peg on the gages but didn't show on the scale). I didn't believe it at first but I've heard similar stories since then.

Well, the report shows all cylinders at 135 compression. None leaked, except cylinder #2, which dropped from 110# to 100#.

Thanks to all for the input.

- Skip

Wow. How much is the car, if you don't mind my asking?

Beethoven- All the dirty details here