Leak down test.....feedback please

[MMiller]

Hello, I'm new to the forum and while I have desired a 911 for more than 30 years I have finally got serious about buying one. I have been lurking around here for a while learning what I can...

I have located a 88 3.2 that I'm interested in. The owner says he does not believe that the car has ever had any top end work done. He has owned the car for 5 years and has good records during that time but prior to is less clear. When he bought the car it had 88K on it now it has 104K.

Leak down test resulted in #1 -4%, #2 -7%, #3- 3%, #4-10%, #5-4% and #6-4%
he also stated that the car is using less that 1 qt of oil per 1000 miles.

My question is this uncommon ( given the valve guide issues) for a car of this mileage to not have had the top end gone through? What are considered good #'s for a leak down test? Total speculation I understand but what might the near future hold for this engine given these numbers?

Thanks to everyone in advance for any insight or guidance

regards,

Mike

[wildcat077]

Mike,

My car,an 89 Coupe now has 127K on it and has never had a top end rebuild either ...I think it leaks more oil than it burns so i'm not too worried about consumption ...

Those engines are really tough when they are maintained properly !

Cheers !
Phil

[RoninLB]

I'm not wild about using a single leak down test alone for engine condition. I figure chances are that the 10% leakdown # will change if the car is driven around for awhile and retested.

my take is that having cylinders hanging out of the case and expanding/contracting does funny things to leak down #'s, where a solid block would be more indicative

how much $ for the '88 Carrera ?

[RSTarga]

I agree with Ronin. To properly do a leakdown the engine must first be at operating temp, then the plugs removed and checked. How many mechanics do you know that will do it this way?
I'd check for smoking or remove valve covers and physically check play on valve guides.

[moneymanager]

I wouldn't pay much attention to this data. My 73 had one cylinder at 20%; I drove that motor another 30k miles without adverse symptoms or really any noticeable issues. If your candidate runs strongly and is otherwise thought to be in good shape, ignore this and move on. Jim

[E Sully]

The only thing I would be worried about with a 3.2 is the valve guides. This will not show up in a leak down or compression test though. This was what the cylinder heads on the 86 I bought looked like. It only had 68,000 miles on it and they were worn. If the guides are worn there is a chance of valve failure. I did a top end rebuild and now it is running like new, but it was not cheap. I would check to see if it smokes on deceleration.

[MMiller]

for your input. Car goes to shop later this week for the PPI. I will have them check the valve guides for play and look for smoke on deceleration.

I will post up some pics if I get the car bought..

Thanks again

Mike

[RoninLB]

what i used to do is decelerate a lot, which sucks oil, if available, into the combustion chamber, then floor the gas pedal

if it sucked oil you'll see the color

gas is black, oil is like a dark grey