Hello again,

I built a 540bbc over the winter and am seeing a lot of oil out of the valve cover breathers. Made a pass yesterday and thought I blew the motor up when I took my foot off the throttle. Lots of smoke. Popped the hood to find the engine bay covered in oil. This is a 3000# car, PG with brake. Car went 9.82 @ 134 with a horrible 1.44 60' (car normally runs 1.2x) and on the rev limiter for the last couple hundred feet. Seems like the engine is pretty strong. It has not been on a dyno.

I've tried 2 different sets of valve covers, 2 sizes of evacuator setups and now a set of open to atmosphere breathers thinking I had a crankcase evac problem. Going to do a compression test but I'm looking for other ideas regarding the source before I pull the engine out and disassemble. Rings maybe? Valve stem seals? Head gaskets? Everything is new, no used parts in the engine.

Breathers at front of valve covers or rear

Have you checked to see if a baffle is installed beneath the breather hole, maybe too much oil being pumped up through lifters, might need a hose-pipe joining oil pan [above oil level] to valve cover to equalize pressure.
this is the for what it's worth department. Good luck and I hope one of these ideas work for you.
See Ya

Also how much oil are you running could it be over full

Breathers are at the front of the valve covers. These are baffled valve covers.

7qt pan with 7 quarts of oil.

I believe a look at the spark plugs and a leak down test will reveal your problem.

What kind of ring package ? Gap ? Vent/filter at mech fuel pump housing ?

Bummer!!

As said leak it, identify the bad holes. Take dingle berry hone knock the glaze off those cylinders and put new rings.

I've done it and had it back together running in a day, by midnight.

Too much crancase pressure. Could be broken ring(s) or piston. Doubt you burned piston unless you run nitrous or a blower.

I had si,ilar deal with first injected motor we built back in 85. Switched to total seal and problem gone. Not saying you need total seal rings just that rings where issue.

It could be as simple as to much oil in the top end. Don't spend a bunch of money finding out that you haven't fixed the problem.

7 quarts is a lot even in a 7qt pan. I’d drop to 6 or 5.5 and see if there is any difference.

Do you have check valves in the headers? If one is bad it will allow air into the crank case and pressurize one side, blowing oil out.

quote:

Originally posted by Roger McGinnis:
It could be as simple as to much oil in the top end. Don't spend a bunch of money finding out that you haven't fixed the problem.

Should I be planning to add flow restrictors of some kind?

If it only smokes when you lift then it's likely oil sloshing forward and flooding the area where your header evac tubes are which could be due to location and or too much oil up top. Too much oil up top is usually due to no restrictors in the block. Some heads also hold more oil upstairs than others which makes things worse. Normally conventional headed BBC do not need drain back hoses.

If it smokes under WOT then you got ring issues.

Not the exact problem but I once had a evac tube to the header from the valve cover located right over a rocker arm and it was throwing oil right up into the evac tube....looked like I blew the motor every time I went down the track.
You obviously have either a oil return problem OR something causing way to much crankshaft pressure.

Are the lifters modified to increase oiling to the rockers?

quote:

Originally posted by Duane1791:
Are the lifters modified to increase oiling to the rockers?

No, just standard +.300 Howards solid rollers.

quote:

Originally posted by CSRacing:


Should I be planning to add flow restrictors of some kind?

Yes, and opening/smoothing up the drain back holes

are you on gas or alky ?

I have had the same issue in the past.