compression question

[MoparmanFl]

When doing a compression check by adding a teaspoon of oil to a cylinder .If the compression remains the same ,does that mean its a bad head/valve ? on a 360 small block

 

[AJ/FormS]

It might...... It kindof depends how it compares to the other cylinders
For instance two side-by side cylinders, both low, could be a headgasket.
Or if all cylinders are close to the same, it could be perfectly normal.
But if it reads under 100 on a known good gauge, well then you have probably nailed it.

 

[moper]

Potentially yeah, like AJ said. Easiest way to see where the compression's going is use shop air and an air-hold. You can hear it escaping and tell through what by where the air's going.

 

[nm9stheham]

If the added oil does not raise compression readings, then you have shown that the rings are not the main source of any leakage. So, yes, it is very likely in the head area, unless there is literally a hole in the piston somewhere!

 

[MoparmanFl]

Thanks

 

[MoparmanFl]

also Wanted : A 4 core radiator for an A body. Thanks for any leads . I'm in central Florida.

 

[krazykuda]

When doing a compression check by adding a teaspoon of oil to a cylinder .If the compression remains the same ,does that mean its a bad head/valve ? on a 360 small block

If the wet compression is higher than the dry compression, then there are problems with the rings and bore sealing...

If the wet compression is the same as the dry compression, the rings are fine and you need to look at the valves and/or head gasket....

If you know which cylinders are low, then do a leak down test to see if it's in the intake valve, exhaust valve, or crank case...