Engine Compression

Try a leak down test.

You put a tablespoon of oil in the plug hole and try again. If it comes up, suspect rings.

Mike

86/00 CJ7 Laredo, 33x9.5 BFG Muds, 'glass nose to tail in '00 88 Cherokee 235 BFG AT's Canadian Off Road Trips Photos: Non members can still view! Jan/06 (More Off Road album links at bottom of the view page)

If it *doesn't* come up that doesn't necessarily mean valves however. there's a third possibility which is that there is a leak in either the head gasket or the head or block. Hooking up shop air to the plug hole with the engine rotated so the valves are closed will tell you a lot.

good luck

nate

NO compression? That's unlikely to be rings. More likely a burned valve, dropped valve, holed piston, blown head gasket, etc.

You could perform a wet/dry compression test cept you have NO compression, indicating that you have a bigger issue - 1st Drain the oil, and inspect to see it there is aluminum or pieces of metal.

You hadn't mentioned what year/make/model/engine size...you might try removing a valve cover or you could drop the oil pan - some vehicles have magnets attached to the bottom of their oil pan...

What precipitated this test? What work was done? How was the car running before?

I ask because we once set the valve lash way off on my race car and had zero compression...

Like Mike said, some oil in there will help seal the rings... but if you have ZERO compression, you probably have a valve stuck open or some other serious damage...

What kind of engine? Ray