Crank case pressure
 

I seem to have a lot of oil residue sucked in my carb. (I think it's a lot) Anyway, I wondered how most engines ran their blow by. Through the carb or what? I thought my engine was running fat due to jetting (black residue on the transome after running hard). But now I beleive it is just burning oil.
Any thoughts or suggestions?
Tom

Re: Crank case pressure
 

My old Chevelle had a similar problem with crankcase pressure. It was a bent connecting rod. Is it making any strange knocks or sounds, especially at idle?

Re: Crank case pressure
 

blowby is usually cased by the ring /ring gaps

Re: Crank case pressure
 

Most basic MerCrusiers vent from valve covers to flame arrester. Oil running too hot will result in lots of oil vapor going into the carb. But a leakdown test will tell you if you have blow-by issues. --- Jer

Re: Crank case pressure
 

Thanks,
I use to have a simular problem with a street car myself ,but that was due to a large ring gap. This engine has an oil cooler. it doesn't have and oil temp. Basicly I'm wondering if it's a problem to just run large valve cover breather/ filters? I haven't run any leak down or compresion tests, but the engine seems to run very well. From what I was told it has about 40-50 hrs on it. 10:1 static ,540 ci ,camfield alm. heads, hyd roller, holly dominator, e-top cmi, 625 hp

Tom

Re: Crank case pressure
 

As stated above do a leak down test just to verify you have no problems arising. An oil temp gauge is always good to have, that way you know whats going on while running under load. What weight oil are you running, too thin may help with excessive blow-by??? Just some other thoughts good luck, keep us posted.