Ppi?

wurls · 02-01-2010, 09:33 PM

Guys,

I am wondering how long a good PPI should take, and what kinds of things extra should I get the shop to check? I heard that leakdown tests aren't normally done on a PPI because they are very time consuming. Is this true>
I hope not because I want as thorough a PPI as I can get as I am looking at getting a 930 and want to make sure it hasn't had the piss driven out of it.

What should a good PPI cost?
How long does a leakdown check take?

I realize a PPI on a 930 will take longer because the intercooler will need to be removed for a leakdown.

Any info?
Thanks!

aigel · aigel's Garage

The only difference between a leak down test and a dynamic compression test is that the tech has to put the cylinder under examination at TDC - ignition stroke. I guess it should not cost more than an hour labor to get leak down and compression numbers. Of course that will be in addition to the rest of the PPI. Anything you can have checked on the engine will be money well spent. Rings like to go on the 930s if they run lean or get run on too much boost. I am no expert on these engines, but if they have the Dilvar studs, also have them take off the lower valve covers and check for broken studs.

HTH,

George

wurls · 02-01-2010, 10:09 PM

Quote:

Originally Posted by aigel

The only difference between a leak down test and a dynamic compression test is that the tech has to put the cylinder under examination at TDC - ignition stroke. I guess it should not cost more than an hour labor to get leak down and compression numbers. Of course that will be in addition to the rest of the PPI. Anything you can have checked on the engine will be money well spent. Rings like to go on the 930s if they run lean or get run on too much boost. I am no expert on these engines, but if they have the Dilvar studs, also have them take off the lower valve covers and check for broken studs.

HTH,

George

George,

Thank you for the info. I'll keep it in mind for the PPI.

nineball · 02-02-2010, 07:04 AM

i had several ppis performed last year across the country in my quest for a car. they ranged in price from $250 to $600. on average expect a quality ppi to take 2-5 hours at the normal shop rate, with a leakdown and compression test resulting in the longer times. there is a ppi checklist posted somewhere on this board that you can email to the shop as well.