cat4 compression

does anyone know what the compression should be for a D4 7U 42984 ?
thanks
bud woodland
[email protected]

CAT never published compression specs, but Eddie dug up some unofficial specs and posted them a while back. A search for compression and user name edb brings it up here......http://www.acmoc.org/bb/showthread.php?10538-Welcome-JoePrue66&highlight=compression

Most don't have a diesel engine compression test set and most of the time, some educated guessing while knowing the condition of the injector valves and pumps as well as watching the exhaust and blow-by from the crankcase breather will get you to the same place as the actual compression numbers. CAT did recommend a cylinder blow-down test where compressed air is plumbed into the cylinder while the piston is at TDC compression stroke, so both valves are closed. The official CAT test apparatus had a specific sized orfice and a regulator to regulate pressure resulting in a range of numbers to compare with other engines, but a lot of good information can be gained by simply putting the air pressure to it and listening for leakage from intake and exhaust valves in their respective manifolds as well as rings/piston problems by listening in the crankcase and also looking in the radiator for bubbles.