450 Engine Compression???

[James3504]

My 450 has developed an oil leak very rapidly from the rear main. I was wondering if anyone knows how many pounds the compression should test at. I was trying to eliminate potential factors that could be causing it to start leaking so much all the sudden. Could it of broke a ring possibly ?? I'm not seeing no blue smoke from the exhaust, that leaves me puzzled. Any ideas or suggestions would be great. Thanks

 

[ihc49er#2]

gas or diesel? rings not likely, your blow by would find its way out other ways than the rear seal.rear seal just worn? maybe camshaft plug.need more info. when cold, warm, how much oil is leaking. do you have lots of blowby?how did it start leaaking?like dripping slow or just pouring out.regardless it still has to come apart.

 

[mkirsch]

Wouldn't leaking oil from the rear main indicate that the rear seal went bad? Why would you think it's compression related?

Excessive blowby won't pressurize the crankcase and blow oil out the rear main, unless the breather is plugged. More likely, you'd see excessive smoke out the breather.

 

[Red Mist]

I don't see how compression is going to have anything to do with a leaking rear main. Now, if your crankcase vent is clogged, that might have something to do with it.
When you tear it down to fix it, check out your main bearings. Seals usually don't start leaking unless what they are sealing starts moving around too much. In your case, that would be the crankshaft. Good luck.
mike