A leak down is going to tell you about the valve seals. A compression test won't since it's a max pressure kind of test with a peak-hold gauge.
The leak down test is dynamic and will let you know if pressure slowly (or quickly) leaks from the cylinders. Then you can listen and try to figure out where it's leaking from. Good luck! Mark On Mon, Jul 20, 2009 at 12:48 PM, Rob Ebersol <[email protected]> wrote: > I've picked up a new-to-me 90 to move my FE driveline over too. Until > I have a garage built, I opted to just stick another 1.6 in it to > replace the blown unit and give me a DD. So now that it's in and > running, I'm getting horrendous smoke on startup. After it has been > running at normal temp for awhile the smoke is gone. > > I also pulled the pcv valve and that changed nothing. > > The engine has sat for 4 yrs, so I expected the possibility of valve > stem seals, but the fact the smoke goes away, makes me think this > isn't seals. So I figured rings - sealing when they get up to temp. > > I pulled the plugs and number 1 & 2 had trace oil on them after the > engine had started and run for maybe 15 seconds. 3 & 4 were fine. > Next I did a compression check and here's what I saw: > 1 = 180psi > 2 = 179psi > 3 = 175psi > 4 = 178psi > > I thought that compression looked very good for a 92 1.6. The > cylinder head is spotless, no oil staining and the piston stops don't > have hardly any staining/carbon on them- you can see the metal. > > Any suggestions on where to go from here? I considered check the head > torque - maybe I've got a gasket that leaks into the cylinder when > it's cold and seals when hot. I had that with a coolant once. The > only time I've had bad valve seals (another engine that sat forever) > the engine made oil smoke all the time... or am I wrong and thinking > it's NOT valve seals? Thoughts? > > thx-rob > _______________________________________________ > Miatapower mailing list > [email protected] > http://list.miatapower.net/cgi-bin/mailman/listinfo/miatapower >
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