Thread: small block question

Tweet

i just bought a 64 el camino. it has a 327. i noticed a lot of oil all over the block and on the intake manifold. the oil looks old and gummy. i removed the air cleaner and noticed that it too had oil clogging it. there is a tube that runs from behind the block and to the bottom of the air filter, the oil apears to be coming up through this tube and into the cleaner and then onto the rest of the block. My questions are, What is this for?, Can i take this tube off and plug the hole? The tube is metal and about 3/4 inch wide. If i take the tube off, can i simply drill a hole in the valve cover and add a breather? And finaly can i re-route the line to the valve cover so the oil goes back into the motor? Any advice would be apreciated. thanks

That's part of the crankcase ventilation system or PCV. The engine sucks air through the engine to draw out oil vapors and such and burns them inside of the engine. Excessive oil coming from the PCV system is generally a result of worn piston rings. When put under load gasses leak past the rings and carry oil out of the crank case and deposit it all over your engine.

Replace the PCV valve before you get to worried about worn rings though.

the tube is for crank case vent there should be a hose going to the other valve cover with pcv valve pre 66 blocks have vent internal in the lifter valley more than likley you have worn valve guides. These engines also used a o ring for valve stem seals and they are wore out or gone altogether. also pull valve covers and make sure the oil return holes are not clogged for this will let oil past valves.

Thanks for leaving the curser in the post Denny, for a second I thought my mouse screwed up

hey guys, thanks for the great info. i was going to replace the pcv valve first to see if it solved the problem for now and i relized that there is no pcv valve! i checked the tube and even the base of that tube where it connects to the block, nothing. If i run the pcv valve, which way do i run it?, Does the tube suck air into the block or does it push it out to the carb?

Or you could take the more extensive route and pull your pistons, have your motor bored and fitted for new rings/pistons depending on the overbore. I would personally go for the baffled pcv

the only engine that uses a road draft tube is the 55 265 all other small journals had a can inside the intake valley no pcv valve from there they went to a pvc system. ont this sytem you have air goining into the into the crank case from the air breather. it then goes through the crankcase to the pcv valve then to manfold vaccum usually bottom of carb or the intake.

one last question just to be sure, i will run the breather with a hose hookup, from the valve cover to the base of the carb. i m running a q-jet , so were exactly do i hook up the hose? my 65 has the same setup but it has a holley, the q-jet looks damn confusing. Also, i will need to drill a hole in the valve cover, once this is done i assume that i will no longer need the hole in the back of the block were the old tube was, if so, is there a special block-off plug or plate? thanks.