Thread: White smoke from breather and oil drops formed

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THIS IS A BRAND NEW REBUILD.Brand new rings, cam, everything.... Ive got smoke billowing from the breather. Pcv is fine it has vacuum. I havent done a compression test since this problem started. During break in procedures (2500-3000 rpm for 30 minutes) this motor was fine. I finally got my breaks fixed on my 85 c10 and decided to drive it to work. When i got to work i noticed i was burning oil off the headers. When i took a look i thought at first my valve covers were leaking. After further inspection noticed white smoke and oil drops forming and dripping from the breather. I am aware of what could cause this but they are BRAND NEW RINGS! I have so much invested into this thing and have spent months getting this truck ready and rebuilding this motor and its first drive im already debating pulling the motor out and having to rebuild it again. I have eagle rod and pistons, comp magnum cam, brand new pushrods, calve springs rockers, pretty much everything but the heads which are aluminum zz4 off an old corvette and an old 400 sb 4 bolt main bored 30 over. Everything checked out at the machine shop. Please i need some real solid advice and PLEASE no redneckery. Thanks in advance

First, welcome aboard. it's good to have you here.
What else can you tell us about the valve covers? are the baffled inside? How about the breathers? Do they have a filter or baffle system?

I wouldn't condemn the rings just yet. Some oil vapor inside the motor is normal. Also, who assembled it? You or a shop?

Both sides are baffled and i believe the breather has a filter as well as a metal flap just inside the bottom. Also i assembled it myself.

Just tested the first cylinder. I got around 90 psi off the first stroke and then after another turn or 2 it topped off at about 155psi

I've been looking for some pics of 400sbc machine work and cracks on dect from STEAM holes but won't repost them because of size issues on this site-----if you can do a search and find them you can see how it is fairly common for the bolt holes and steam holes to crack toward the upper cylinder wall------

Im testing my compression atm and if all the cylinders check out, what is the next corse of action? Btw, my spark plugs are black. This motor has prolly ran for a total of MAYBE 4 or 5 hours

What oil are you using? Conventional oil is better for break in as synthetic is sometimes too slick for the rings to seat properly.

Half royal purple 5w 30 half conventional with 12oz comp cam break in

Update on pressure
cylinder #
2: 145
4: 155
6: 150
8: 165

Have more than a few times on engines brought to us that were assembled with the royal purple type stuff had to disassemble, rehone, new rings and reassemble ---------

UPDATE!!:
CYLINDER NUMBER (PSI):

1: 150
3: 78
5: 55
7: 48

I have a feeling it is the head on the drivers side.....
like i said brand new rings so it was hard to believe it would be rings.
Excess oil/air coming out of both valve covers. If it is the head would it still be overpressured on both sides and also burn oil in EVERY cylinder?? (Again all spark plugs are black)

Exhausr also has blue smoke so it is definitely burning oil...

Most likely the blow by is increasing the crankcase pressures and the PCV is taking the oil into all cylinders.

Ok i appreciate your input but whats the fix?

Can someone tell if i should be looking at the heads as the culprit or somewhere else?

Check your valve adjustment first, make sure valves at #3, 5 & 7 are not tight. Re-check compression, on low cylinders squirt some oil in each cylinder (one at a time) and re-test the compression. If the rings are leaking the oil will temporarily seal the rings and the compression will go up.
If the compression remains unchanged, make sure the valves are closing by slightly loosening the adjustment and re-test (make sure the valves are slightly loose on their closed adjustment). If the compression is still low, remove the rockers on the low cylinders and pressurize the cylinders (one at a time) with compressed air through the spark plug hole and listen for where the air comes out. If you hear the air through the intake port, intake valve is not sealing. If you hear the air through the exhaust, exhaust valve is not sealing. If you can't hear the air exit or you hear it through another cylinder, you have a blown head gasket or cracks.

So you have breathers on both valve covers??


What head gaskets did you use??


Where is the PCV plumbed into the system??


To help try getting rings to seat you can lightly sprinkle BonAmi powder into the air horn on the carb while revving the motor --will help with the seating of the rings and valves-------


You said heads were off an old vet??????? any valve work? guides/seals?? drill steam holes??


Any sleeves in block??


What type intake manifold?? good seal at front and back cylinders next to water passage in heads/manifold?


Did you get it warm/hot enough to vaporize condensation from leaky combustion??


Any pressurasation of cooling system??