The Stovebolt Site Forums The Shop Area The HiPo Shop Oil breather blow by

I have a gm 383 crate motor that I've built
up using Edlbrock heads, cam, roller rockers, etc. The oil breather on the drivers side is
getting oil blow by. There is a baffel in the
cover and the one on the passenger side has no
problem. Its a small amount of oil, but it
still bugs me. I have a feeling its when I get
on it that it does this. The engine probably puts
out between 425-450hp. What would cause this
and why one side and not the other? The engine
has less than 2,000 miles on it. The oil
breathers are the chrome gm logo type with a
small mesh filter.

My guess would be the valve cover baffle under the breather, isn't keeping the oil from splashing up the cap. That's why most race car motors run an extended pipe from the valve cover to the breather cap, for high rpms. Make sure there is no direct oil splash, able to get to the breather cap. The reason it doesn't do it until you turn the motor hard, is beacuse the oil isn't there in a large quanity, at lower rpms. I can't explain why the left blows and the right doesn't, except there may be more oil, coming off the pushrods on the left side.

I have the same problem except that I have an original inline 6 engine on my '46 pickup. The gasket seems to be tight, but the cap is rusty and may have some of the stuffing missing inside. Is that enough to cause the problem?

I'll try and find a taller breather cap or one
that also has a baffle in it.