Blowing oil

[79Challenger]

This might be better suited in the geargead section but the motor is im my jet boat so here I am. I swapped a 454 for the 396 the boat came with at the end of last season. This week was my first real time with it. The motor came out of an identical boat, but I don't know anything about it other than it is a 454 with a slight cam. Anyway, it blows oil out of the breathers pretty good. There are baffles at the breather opening inside the valve covers, the breathers are just mushroom style. Seems I have to run real cold (100-115) just to keep it to a minimum. Some people have told me that some motors are just prone to this due to varios reasons.
Any ideas?

[Duane HTP]

Try a new pcv valve and all of the normal things, but sounds like a case of bad ring seal.

[502 JET]

Make sure your oil is not overfilled.Do a leak down test on your engine this will show if there is any problems.
I had this problem with my 502 and I ran hoses from the valve covers to a puke tank.I had two cylinders that were leaking 28 % into the crankcase.When I tore down the engine the rings on those two cylinders were close to being lined up.I also had four cylinders that were pitted at the bottom from water sitting in the them.Luckly the cylinders will clean up with out boring to the max.The water that pitted my cylinders may have been from condensation or the previous owner leaving the boat sitting with rain water in it.I think the pitted cylinders helped contribute to the blow by that I was experiencing.

[beerjet]

Try a new pcv valve and all of the normal things, but sounds like a case of bad ring seal.
Duane must be the man . Mine used to cough up oil all the time . I put new baffled valve covers on with mushroom style breathers and it pushed the rear intake minifold seal out. Put a pvc valve on it and no oil spills. But from the looks of the old timing chain , it might be time for a rebuild .
-beerjet-