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Discussion Starter #1
So i have a small block 383 stroker and i recently went for a drive and lost oil pressure. I checked and the motor was almost out of oil. (I know i should check before i drive) so upon further inspection i have come to find that the oil is actually pushing out through and oil breather that is on top of the valve cover on the drivers side. Is it possible that the guy who built the motor mistakenly assumed a breather would work and it should actually have a cap? Should this motor even be throwing that much oil? the motor runs amazing when its full of oil but i cant keep adding quart after quart this needs to be stopped. Thanks in advance
 

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Check and see if there are baffles in the valve covers and post where the PCV valve is ported to.
A pic might help too.
Also ,with the engine running ,remove the breather ,slightly rev the engine and feel if there is pressure comming from the breather hole -should be slight not massive.
Start there.
 

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Discussion Starter #4
thanks, ive also ordered a compression tester as well on a friends advice and im going to test all the cylinders. i wasn't present for the engine build and there could possibly be incorrect rings on the pistons causing too much blow by as well. time will tell.
 

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Sometimes a rocker arm is squirting oil directly into a breather or a PCV valve and this will cause excessive oil use issues.
This is when the valve covers do not have baffles like Mike stated.

There are 2 threaded holes on most GM blocks on the front of the block where the fuel pump is located.
One of those holes is threaded through into the cavity that houses the fuel pump pushrod.. it needs a short bolt in it..
You know what I am talking about??
 

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5 quarts of oil out the breather? I don't think so. It's more likely that oil was blowing past the valve seals which is a very typical problem when the heads aren't rebuilt properly.

A single breather won't work either, you need either a PCV or a road draft breather set up.
 

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Discussion Starter #7
Seems like the baffle fixed it. I do also have a PCV valve on the other side but i think it is also unbaffled so im going to remove the pcv and baffle and breather that side as well. Thanks for all the help guys!
 

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Leave a breather on one valve cover and a PCV on the other.
Check for the baffle on the PCV side and add one if necessary but don't eliminate the PCV valve.
 

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Boldly procrastrinating
66 El Camino 57 Chevy pickup 2004 Tahoe
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What Mike said, you can't run with 2 PCV and no breather. You need a high volume breather like the factory used. otherwise, pressure will build in the crankcase anytime there's heavy throttle. Heavy throttle = low vacuum and high blow-by.

Nothing new or different here, known since the 60s.
 

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Seems like the baffle fixed it. I do also have a PCV valve on the other side but i think it is also unbaffled so im going to remove the pcv and baffle and breather that side as well. Thanks for all the help guys!
Un-baffled flat out will not work. Of course we like to assume that baffles were used in every case but not all valve covers come with them installed.

I run dual baffles for both breathers but I'm using a road draft set up on one side because PCV's are near useless at high RPM's which is when you need them the most.

I would suspect there would be some carbon build up on your plugs at this point
 
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