Thread: Oil vapors through breather cap...

Tweet

Hi there,
I'm having a problem with my 350 SBC again (as always, actually ) When I start the engine it starts very nicely, but after a short time oil vapors start coming from the breather cap, which is located on the driver side valve cover. I have a PCV-System installed on the passenger side, valve is new and so are the hose and carb. You don't see it when idling, but if i open the throttle about a quarter fumes start pouring from the cap. The engine doesn't have to be fully warmed for this to happen.
Does the crankcase ventilation only work in one direction and am I maybe running it the wrong way around?
Please help me out on this one, I've tried replacing the valve, but the problem doesn't seem to be valve-related...
Thanks a lot,
MadMax

It doesn't matter which side the valve is, it'll work. If your engine has too much blowby past the rings the PCV won't be able to handle it, and fumes will come out the breather.

u could have the wrong PCV or there is no baffle in ur valve cover.....joe

Joe---tell us more about the baffle in the valve cover. I have a chev small block in my roadster pickup, and although I have the same setup as the person who started this thread, my problem is oil being forced out of the dipstick tube at sustained speeds over 50 miles an hour.

it just a small rectangular box w/basicly a louver or 2 punched in it thats normally under the PCV & the tube going to a stock air cleaner.
unless both of u have a lot of blow by then u have got to have the wrong PCV in it or if ur running a draft tube it's stopped up...joe

I do have baffles in my covers, and nothing is blocked. Checked that. Can I find out the blowby of my rings with a leak-down-test? The engine is newly assembled and has had a three angle valve job done, so I don't think the valves are losing fumes, but that could be, too, couldn't it? Anyway, the guy who rebuilt it certainly wasn't the best engine builder out there... All sorts of things were wrong and didn't fit when I bought it, so possibly the rings are junk, too...
How do I find out?
MadMax