502 oil blow out
 

Had a friend that this happened to this weekend and I am scratching my head. Formula 27' with a 502mpi stock rebuild with 60hrs since rebuild. shows up at our raft up and we smell oil, look in engine room and the motor puked out 3-4 qts of oil on the stbd side of the engine. get him some oil and fire it to see where it came from and can't find a leak anywhere, Dipstick looks good at the pan, valve covers/ pan not leaking. gets home cleans it out runs again on Sunday... no problem found. WTH? No blow by from valve cover etc I don't get it. Any ideas?

Maybe the oil was cold and he did not let the oil get warm before getting on it and it blew pass the oil fiter seal due to the fact the oil filter is not tight enough maybe.

Was there oil by the intake .I burnt a hole in a piston last year and the oil pumped out and locked up the motor, mine are efi motors ,how did motor run on way back?

the oil came out of the dipstick side not the oil lines/ filter/ cooler side... It ran great back to the marina. He went home cleaned it up and was out the next day/ sunday.. No probs..Weird, really weird

Yeah, I talked to Ryan on Sunday about this as well. Couple years ago I put a hole in the piston and only symptom was oil in the bilge after a high RPM pass (combustion blow by would create positive crankcase pressure would push the oil up and out the dipstick tube)....normal cruising and the PCV system can keep up with the added pressure. The easiest check I found was to place a tissue or paper towel over the oil fill neck and fire the engine. If blow by is not the problem, the paper will dish in and remain concave; however if there is any flutter you may have a bad jug and a compression test is the next on the to do list.

For his sake I hope he doesn't have a hole in a piston... That would blow his year up

missed the MPI part

I am pretty sure the 502 mpi's are plumbed to the intake plenum near #8 cyl..

I would do a compression test or leak down. There has to be a lot of crank case pressure to push out 3-4 quarts of oil through the dipstick. It may not be a hole in the piston, but could be the top ring land damaged, broken ring and loosing most of the compression down the cylinder. Either way a leak down or compression test would show the bad hole. If they test fine then go looking for other problems, but I bet you will find a problem that needs addressed before major problems take out the whole motor.
A bad cylinder is not the end of the world and a fairly easy repair, compared to replacing the whole motor. Good luck to your friend!

I am lending him a compression tester and leak down tester this weekend. Hope all is good