PPI results question

davidrivers · davidrivers's Garage

Hey guys..

Lost my NA 84 911 last fall in a collision and have been hunting 930s for the last little while. I found one that might be of interest, and have had a PPI performed. Leakdown and compression results below. Compression seems low and leakdown seems high to me, but wanted to confirm if numbers vary at all with 930s.

Car is an 88, approx 70,000 miles
Not been driven in 2 years, started and run occasionally

LEAK DOWN
Cyl #1 = 10%
Cyl #2 = 20%
Cyl #4 = 10%
Cyl #5 = 15%
Cyl #6 = 14%

COMPRESSION
Cyl #1 = 131.5
Cyl #2 = 130.5
Cyl #3 = 139.0
Cyl #4 = 135.0
Cyl #5 = 142.0
Cyl #6 = 138.0

Thanks all!
David

matt demaria · 08-17-2011, 02:18 PM

Assuming that this is a warm leakdown, in my opinion it is too much. 10% is very old; more than that- engine time. But kind of expected for a turbo rode hard for all that mileage

JBL930 · 08-17-2011, 02:26 PM

I'd say maybe it could improve with a good run, but the fact that it's the two middle cylinders with the worst numbers it's pretty certain it needs a top end rebuild...... It'll be the exhaust guides more than likely. Price in for a top end, opportunity to do a few mods while you're in there, it could play to your advantage as long as you're not in a hurry

Aggie93 · Aggie93's Garage

The two PPIs i did came back with leak downs in the 5-8% range. Only did compression on one car and were between 120 and 125. Both cars did have recent rebuilds (within 15k miles).

As JBL930 said, get it priced in and start the "while you're in there" mods.

davidrivers · davidrivers's Garage

Thanks for the feedback.. leakdown was performed cold.

Starting the price discussion with a rebuild in the discount plan :-)

Noah930 · Noah930's Garage

The problem with a cold leak-down is that you don't really know where the motor stands, IMO. On my PPI I think the leak-down was done with the motor cold. (And to think, this was done at the Indy Porsche "specialist" in the Reno area.) The values were in the range you listed above in your prospective purchase. That was about 25K miles ago. My car had about the same miles then as the one you're looking at.