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cab83_750 cab83_750 is offline
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Join Date: Oct 2000
Location: agoura hills, ca 91301
Posts: 2,625
This is educational and surprising for someone reading up on Wayne's rebuild book.....though I am not currently 'actually' rebuilding.

I am monkeying around my SC, ready to drop and replace the tranny. While I was there, I started checking the compression. Then, as if I have a lot of time, I wanted to test my new leakdown tester. The manual mentioned about TDC.

So the basic assumption/requirement behind the leakdown tester is that both valves are closed and they have almost perfect air sealing to the heads. Then, air/pressure would escape via worn rings, pistons, cylinders, etc. Correct?

However, if timing is incorrect, air would escape via the intake and/or exhaust, thus preventing you to diagnose rings, pistons, cylinders, etc. Better yet, if the heads are not perfect, or you have head studs problems, this is yet another avenue for air/pressure loss. Right?

As I said, I am just religiously reading and learning about rebuilding, thus the title of "Stupid Question of .....".

Thanks a lot guys!
Old 01-30-2004, 08:51 PM
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