72 911t 2.4T leakdown & compression results

[Skip Newsom]

I spent a couple of hours testing the condition of my stock 2.4 MFI with 90k on it, the engine has had no major work done.
It was tested warm, and retested to check accuracy... I did a complete tune up including valve adjustment about 500 miles ago, mfi, timing and every thing else is spot on. The #1 plug is always very dark.

The results:
#1 18% 80psi
#2 7% 85psi
#3 8% 83psi
#4 7% 100psi
#5 9% 90psi
#6 6% 92psi

It seems odd to me that the left bank would be so much lower on compression than the right. The engine starts and runs fairly well, it had sat for several years at the PO's garage. I"ve dropped the motor, cleaned it up, replaced all the easy gaskets and seals already.

Impressions?
Would you rebuild at this point?
Any one have a free 3.2 they want to get rid of?

[BK911]

I wouldn't rebuild yet, but your compression seems pretty low. I would look for something around 150 psi and all within 10%. Since both banks are pretty consistant I would check the cam timing first.

Since the car sat for awhile you might have gunked up oil on the bottom of the cylinders. I'm not sure how many miles you've put on the car, but maybe some stuff just needs to burn off the cylinders and/or valves to get better results. Maybe you just need to add some berryman and keep the car ~4k rpms for a while. Even if it doesn't work, at least it was fun!

Good luck!
BK

[Jim Sims]

I would put the plugs back, use some Techron in the gasoline and run it for another 500 miles (get it up to operating temperature several times and keep it there for an hour or two) then change the oil and redo the compression and leakdown test. Perhaps there is stuck ring or other carbon problem. Others may have more or better advice. Cheers, Jim

[Skip Newsom]

I've put a total of 7K on it in the last 1 and a half years, I've used berrymans and techron, de-carboned with water, and changed oil a few times.
Maybe all I need is a cool collar???

No 3.2's? OK, I'd even take a 3.6.