PPI ethics/advice - need help!

TimB · 10-17-2001, 09:20 AM

I'm looking at an 81 SC. It's a second owner CA car very much restored though not 100% perfect. It's got all the recommended SC upgrades. The current owner runs a Porsche shop and did all the work as a car to keep for himself, but is now selling to buy a house.
There was a PPI done on the car by another guy who's looking to do a trade plus $ deal.
Question: Is it OK/ a good idea to call the shop that did the PPI and purchase it? I am under time constraints since I will be travelling tomorrow. My other alternative (preferable if possible)is to try to take the afternoon off and get it done by my local shop if they will do it today.

john walker's workshop · 10-17-2001, 09:46 AM

being the PPI was done by a guy that has an interest in the car, i would go elsewhere.

TimB · 10-17-2001, 11:55 AM

Actually the PPI was done by the other potential owner's shop. In retrospect it's probably a bad idea. It could really cause ill will between the current and other prospective owner.

The current owner says he's willing to do a compresion check and leak down test after hours with me there. Of course I wouldn't get the other benefits of the PPI. What exactly would that be?

The thing to note is if the guy sells me a bad car his name is on the line as a Porsche repair shop. I can be a real SOB if I get screwed, but I'd rather avoid that.
The problem is timing. I have meetings all week!

Someone at work metioned a mobile PPI place in the Bay Area, but doesn't know the name.
Any ideas or comments?

Tim

Jdub · 10-17-2001, 12:02 PM

If this guy is willing to do this after hours, I think you have a good seller. If the shop is going to be around for awhile you also have a great resource for fixes.

Remember that beer/root beer, pizza, and donuts go a LONG way towards good will. When I built bicycle frames at our frameshop, we had racers at the back door on Mondays with broken head tubes/forks/dropouts and they knew to pay in food or drink for labor; parts at cost.

It really helps things, but do be careful with bringing alcohol into the shop as you might be liable for problems unless you let the manager (overage) distribute.

Jw

TimB · 10-17-2001, 12:06 PM

If I go this route, what should I look for in the compression and leak down tests?

Thanks again

Superman · 10-17-2001, 01:05 PM

I feel as though I know enough about these things to generally assess one, particularly if it seems like a safe bet anyway. I will never again buy a 911 unless I know it has 24 head stud barrel nuts. That's probably the most critical single thing, and can be verified with a small mirror while the valve convers are off. Compression and leakdown are interesting. I'd drive the car to see if it has any trouble shifting or staying in gear. I take a gamble on a car that checks out okay in these areas and seems generally to be a well cared-for car.

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'83 SC

john walker's workshop · 10-17-2001, 01:05 PM

depending on the gauge, engine temp, and cranking speed, 160-170 is normal. nice to see them within 10 pounds of each other. leakage, engine hot, should be 4-6% best case, or at least under 10% if it has 100K orso.

TimB · 10-17-2001, 02:24 PM

Thanks for the replies.
What is a 24 head stud barrel nut? What does it look like and why are they important?
On the compression, I've searched and found acceptable readings as low as 140 and as high as 190, with a max 10% or 10 lbs difference being acceptable. Apparently there is a wide range. I think this guy said 4 of the readings are 164 and 2 are 158. I will check it out tonight. The car has 121k miles, but the engine only about 10k since rebuild 1 year ago.

Superman · 10-17-2001, 04:19 PM

911 engines have a habit of breaking or pulling head studs. Head studs are long studs that screw into the case. the cylinders slip over them, then the heads and barrel nuts on the ends of these studs are used to hold the heads and cylinders down onto the case. There are four head studs, and four barrel nuts per cylinder. 4 x 6 = 24. My car has 23 barrel nuts (meaning that one of my studs is broken). As a consequence, I will spend lots of time and money this fall or winter rebuilding the top end of my motor.

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'83 SC

TimB · 10-17-2001, 08:19 PM

Did the compression test. 154-156 in 5 cylinders, 148 in the other. The car was warm but not quite operating temperature.

The leak down was 2 in one cylinder, 4-5 in 4 cylinder, and 10 in one.

Overall not too bad except maybe that 10.