964 Compression test results

[Pkblu]

Just got the results from a PPI performed on a 1990 Carrera 4 with approximately 60k miles that I am thinking of purchasing.

While the local dealer said their leak down equipment was not operating they did perform a compression test with the following results.

Cyl #1 - 200psi
Cyl #2 - 205psi
Cyl #3 - 210psi
Cyl #4 - 205psi
Cyl #5 - 205psi
Cyl #6 - 210psi

Other than that the only other item noted was the lower valve cover gaskets have minor oil seepage.

Thoughts?

[KNS]

Those numbers look good. No 1 is slightly low but not a problem, it wouldn't keep me from buying the car if everything else checks out.

[yelcab1]

200 psi, within 5% of each other, is not low.

[Steve@Rennsport]

JMHO,.. but you REALLY need a leakdown test. Those numbers look OK, however oil viscosity and temperature affect the readings.

Leakdown tests OTOH, give you definitive information about valve & ring sealing.

[Marc Bixen]

Do yourself a favor. Go to a local INDEPENDENT shop. If you need a recommendation call your PCA zone rep for your area, Porsche Club of America - Home, and ask him for a good INDEPENDENT. Definitely have a leak down test done. And anyone that says a 1990 964 has no problems except for damp lower VC gaskets either didn't look or isn't telling you everything. Test his knowledge and ask him if the car had the cylinder update, a qualified mechanic can tell visually from under the motor.

[Pkblu]

Thanks Marc and the rest of you for your input.

To make a long story short I made an appointment at a local independent shop that was recommended by the local PCA for a leak down. It was what I should have done originally, but I went against my instincts.

It does suck to have wasted the money at the dealership, and essentially pay twice now for a PPI, but in the long run it is the smart move.

[Marc Bixen]

Good luck with it. I love my 93 RS America 964, great era of 911.