No Compression mystery

[mortimc]

So my GL-10 (which will be for sale) only ran on three cylinders, I narrowed it down to a compression problem, checked it and sure enough that is the problem. I started tearing it apart and got the head off, without taking the engine out mind you. There are absolutely no detectable problems, aside from the fact the cam section which bolts onto the head was missing three bolts. So, im going to put it all back together unless someone has a suggestion.

 

Clayton

[Cougar]

Have you checked the valve seats and the head for cracks?

[GeneralDisorder]

It's not very often that you will actually see where the head gasket failed - sometimes they just do, and it's difficult to see where the leak was. Did you check the head for warpage? It may have just warped a bit and pulled away from the gasket slightly. On the last EA82 I did it was the same way - gasket failed (original - 220k, #3 cylinder tested about 10 for compression), and it still ran on three cylinders - drove it home that way. I replaced the gasket and now it's fine again. I could not see where it had failed either.

 

GD

[idosubaru]

check all the HLA's on that affected cylinder. a bad HLA can cause compression problems as well. check the lobes on the camshaft too. a visual/hand inspection comparing the lobes to the lobes on the "good" cylinder should show major problems. leave the valve cover off when you reassemble and turn the motor over by hand once the tbelts are on. make sure the valves appear to be opening and closing correctly. if this is the case, a bad headgasket wasn't the problem to begin with so you won't notice anything.

 

head gasket leaks aren't typically obvious unless the car is run for a long time with them bad or it's a massive leak.