compression test question

nm9stheham said
I prefer to shove some rope into a cylinder and bring the piston up to hold the valves closed rather than use air.

I would change the seals too before doing anything just to see what happens. The cast a pittance. But the stem to guide clearance may well be way out at this point.

Also, be aware that if the oil rings or 2nd rings are badly shot, then the oil past the rings may make the compression look better than it really is. In that is the case, general performance and other symptoms are the indicators you have to depend on. And a leak down test.

Thank you for input regarding valve stem seals on a 225 Chrysler Industrial gas engine for a 1975 Lull. I have decided and started to replace the seals with the head still on (using the rope-in-the-spark-plug-hole trick.)

Here's where I'm at: When ordering parts for this engine I always use "1970 Dart" (parts counter people look at me like I have 6 heads if I say "Lull") and the parts always fit. Auto Zone supplied me with two seal types: Fel-Pro SS13955 for intake valves (longer "umbrella" type) , and SS12764 for exhaust valves (shorter type.) On my engine I observe that both the intake and exhaust valves have the longer, umbrella types. (I have read elsewhere in this forum that this is acceptable practice.) These seals aren't in as bad a shape as I anticipated and believe that they were replaced somewhere along the line. However, I'm not sure whether they are the right ones for an Industrial engine. They appeared to have worked their way up the valve stems, not staying situated on the guide, which may be the reason why the engine smokes so much. I have installed the new Fell Pros on two valves and it appears the same thing will happen.

I have read that some of the differences between a regular Slant 6 and an Industrial is that Industrials "come with stellite valves, hardened seats, and polyacrylic valve stem seals." I've also read that seals are available "with metal bands around them." So the question is, does anyone know for sure what the proper valve stem seals are for a Chrysler Slant Six Industrial gas engine?