Thread: Oil Blow by

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I have a fairly fresh engine and I am getting alot of blowby out of my valve cover filters, can too much oil in your engine cause alot of blowby? Right now I am going by oil pressure as far as how much oil I have because I have an oversized oil pan, & until my universal dipstick comes in I don't really know how much is in there.

A universal dipstick is adjustable for deep oil pans so you get
an accurate reading as far as how many quarts are actually in there. Please correct me if I am wrong.

OK thanks, now onto the oil that is coming out of the breathers,
there should'nt be that much if any coming out should there? I am
having to wipe the valve covers off after I drive the car, there is usually a small track of oil from the breather.

Thanks I'll give it a try.

Also, you may consider changing the PCV valve and or hoses, checking to see that the port it connects to (carb base or manifold direct) is clear. Shaking the PCV valve and hearing a "rattle" isn't necessarily proof that the valve functions correctly.

Problems with SB Chevys and excessive oil at the top end......The oil is fed up thru the pushrod..The hole in the rocker arm is designed to allow a small amount to be "dribbled" out to lube the rocker socket..Then it travels down the rocker to be "flipped" off the end ...into the lower trough and out the drain holes on each end and into the lifter galley....The hole where the pushrod and rocker meet can get worn to oversize and allows too much oil to run out....It's not dribbling anymore...It's shooting..!!....It blasts the underside of the cover with mass amounts of oil and all that excess oil gets sucked thru the intake valve...Stock engines have an "O" type ring that fits into the groove just under the keeper groove to keep "dribbled " oil from finding it's way down the valve stem...They don't have a chance with all the oil amassing everywhere....Of course worn guides don't help the matter...The new umbrella seals are good..but the fact still remains...there is too much oil at the top.....Guys tend to install high volume pumps ...The stock SB pump is almost completely trouble free and is capable of handling most any situation..except for HPO. and if thats what you want...The drain holes can"t handle all of it so the gaskets take the brunt ....Now this is not a blow by answer....The excess oil thru the guides is burned and taken out the exhaust...............Over the years I can not describe the number of small block Chevys I have scored on for free that all was needed was to stop all that oil at the top end.!!.....I even put pipe cleaners down each pushrod on a 283 once with a high volume pump....It slowed down the oil a lot...At least it quit smoking on start up..........The problem as I see it is....in days of yore the replacement rockers had a smaller ( I called it a metered hole) hole at the pushrod contact.....GM finally cured valve cover leak problems with the new Gen 1 engine etc with a superior drain trough and bigger drain holes and a better cover set up...Since they use the same rockers the amount coming out isn't as important....So the older engine do suffer....because the older "metered" rockers aren't around anymore..................While on the subject I might just as well make it a long one.......The old 235L6 suffered from oil being taken down the intake valves... and excessive leakage around the cover gasket....There again I stopped a lot of them from this by slowing down the amount of oil at the top end...They use a rocker shaft that is fed by a pipe from the tappet galley....In between the front and rear shaft is a coupler that feeds the left over oil back down thru the pushrod holes to the tappet area...As the engine wears and sludge etc get involved.. the drain pipe in the coupler is designed to be ''Pinched " off a little at a time to send more oil down the rocker shafts....So.......after a complete overhaul..new oil pump.....rocker shaft stripped down and cleaned.etc the pinched off pipe in the coupler sends oil flying out each rocker and half way to the moon.!!!....Thats why I always installed a new coupler that had a 'unpinched " pipe..and adjusted it by pinching a little at a time if needed to assure each end rocker was getting enough oil....And then again...the gasket manufactors have come out with better designs that help a lot..You just have to pay a little more for the better stuff...I'll rattle on about blow-by later....maybe......