steve walker

hi have m-t valve covers with vents and notice a lot of i-think is exh blo-by its like oil smoke ???very low mile 15,000 but nothing out the exhaust pipes runs strong still just the smoke out the covers what up with that""any imput???????

Bluevista

Do the the valve covers just have vented caps and there's no PCV hooked up?
I'm not really sure if that much smoke is unusual or not, with the PCV it would get sucked into the carb and burned and you would never see it.
It seems like they all have a little blowby but there are much more knowlegable guys than me on that subject here and maybe one of them will know more.

MN71W30

Blowby=trouble, Unless like bluevista mentioned a PCV problem. Blowby is compression getting past the piston one way or another, rings or cracked piston. But it may just be oil sprayed directly into a breather, Factory covers usually have pieces of metal on the inside of the cover that deflects oil sprayed from pushrods. But if it is chugging compression out of the oil fill tube, you got problems.

380 Racer

What you are seeing is pretty much normal without a proper venting system. Incorporate a PCV valve on one side and a working vent on the other. It will draw those fumes back into the intake charge and be burned just like bluevista said..

66ninetyeightls

Yeah there is always some blow by. Thats the whole reason for a PCV system to releave crankcase pressure.

dhoff

Just don't get the bright idea to put 2 pcv's on the motor to make it look symmetrical and clean. You will get this high pitched whistling noise. I tried that on a 59 vette about 20yrs ago

66ninetyeightls

I have seen people building drag motors pipe the PCV to the exhaust collector. Does this actually work to pull the PCV gases out of the engine?

MN71W30

We installed those on our Bicsayne with a 454. With wide open throttle the vacumme drops very low but you still have some vacuume pulling from the exhaust. It is a pulsating vacuume that does help.

steve walker

yes its got a pvc .loc at the oil fill on timing cover man that sucks I kind new it was that just wanted a diff answer time to redo the orig 425 i guess then swap it out

Texas Jim

Stick a compression gauge on all the cylinders to see if everything is intact. (If it checks out right) That'll ease your mind.

66ninetyeightls

To check for excessive blow by you would be better off using a leak down tester

Texas Jim

If there's a real problem, I'd think it would show up on a compression test. That's not to say that you wouldn't see/find something smaller on a leak-down. IMO, first things first. If I can tell, in 5 minutes, what the problem is, why wait longer? ...and go from there. And in this particular case, it very well may be just a pcv/venting problem. The members on here know more about these big block Olds' than I do.

edj1993

i'm almost ashamed to admit this, but my'63 was blowing smoke and oil out of the oil filler tube and dipstick tube. After a year of putting up with this, I found that my PCV was installed upside down. Once this was corrected, no more problems..