I did a compression check on a cold engine. All cyl. were about 380-420 except of course one- back pass. side (number 7?). It was 85-100.
I pulled off the valve cover and the the rockers and pushrods looked ok, and were tight. I hooked up an air hose to the glow plug adapter and I couldn't get it to hold much air. I bumped the engine through the cycles to what should have been the compression stroke and all the time you could here air leaking into the intake manifold (except when the exhaust valve was open).
The engine seems to be ok, haven't noticed any water in the oil or overheating, pulls 6% hills at 65 etc.

I am guessing it is burnt intake valve. Are there any other tests to check this?

The bad news is I am supposed to be leaving on a trip x-country this week. If it is a bad valve, how bad would it be to drive it a couple thousand miles like that?

Is it possible the valve seats better when it is hot? It seems strange that it runs as good as it does if it basically using 7 cylinders. The truck is a non turbo.

 

my truck did the same thing it was the valve guides with the valve cover off and the rocker arn off grab the top of the valve spring and see if you can wobble it if its loose the valve guide is shot a very common prob on these engines if thats the case dont drive it or you are riskin droppin the valve in the cylinder and killin the motor i put 2 reman heads on my engine in 12 hours it cost me $350 for gaskets plus the heads

 

The valves seemed fairly tight, would only wiggle a few thousands. I guess I will pull the head tomorrow and have a look.