Project 5.GO!

A problem I have been having for a couple years, even after an engine rebuild is the car using oil and it never being explained. I accidentally found out where it has been going when I opened the side port on my Performer upper intake to repaint it. There was a small pool of oil at the bottom inside. Somehow it has been sneaking in there, and it isnt through the hose that connects the oil fill tube to the throttle body (its clean).

I asked a guy at Discount when I was there today and he told me it was a PCV valve that was gummed up, but he called a mechanic he knows, and the mechanic said that there is too much bottom end pressure, which is blowing the oil up there.

Back when I did the rebuild, I took off the smog system, and the original heads had a metal pressure equalizer tube that connected the two, but since the GT40 heads didnt have the ports, I didn't put the tube back in.

I will be replacing the PCV valve again (even though I did it about 12k miles ago, at the rebuild), and pulling the screen and cleaning it. Is there anything else I should be doing to prevent this?

mattkoly

I had the exact problem with my edelbrock manifold...

The lower intake under the hole where the pcv goes there should be a baffle or piece of sheet metal (NOT THE SCREEN OR SPONGE). Pull the pcv, screen, and spong and put finger in hole. If no baffle, that's ur problem. They are supposed to be installed by mechanic and are commonly overlooked

I'll try to find pix...

mattkoly

See step 25 of assembly on this page...

http://www.fordmuscle.com/archives/2...tor/index4.php

Hope this helps.

Project 5.GO!

I distinctly remember that baffle being on the intake when I installed it. I got the intake combo used, and I remember cleaning heavy oil residue out of everything and reassembling it. The baffle is definitely there, which is why im so confused. Is it possible that because there is no equalizer tube between the heads that there is too much pressure that needs a place to go?

Would it mess things up if I let the PCV vent into open air or a collector box instead of the intake? Maybe if I could put a collector box in the line between the PCV and intake, it would at least keep the oil out of the intake. I imagine the oil is either getting sucked into the vacuum lines or dropping into the combustion chamber. Either way, it isnt necessarily a good thing...

mattkoly

Are u talking about the tone on the back of the heads? If so, I think that is for emissions.

Project 5.GO!

Yep. I was thinking that even if it was emissions, it was still venting pressure.

mattdel

Excessive oil pooling in the intake is because you're actually creating a vacuum inside the block instead of just a nice steady vent. If you go with some aftermarket valve covers that have breather filters on them, it should clear up the problem.

Project 5.GO!

Looking at Edelbrock vented covers, and I see they have breather holes, but no fill neck. Am I supposed to remove the filter and pour new oil through the hole? I'm assuming I wouldnt need the tube that goes between the filler neck and throttle body because they are vented.

decipha

you want the crankcase under vaccum, do not run an open breather, remove the screen in the back of the intake under the pcv, install a catch can

/enjoy

Project 5.GO!

Why would I remove the screen, won't that let more oil pass to the catch can? Thanks for the reply!