brettc18

Hi there.

I'm having a problem where oil is being sucked up through the PCV into the baseplate under the carb. The volume of oil is so much that it is building up in the exhaust system and causing white smoke out the back. If I disconnect the PCV and seal off the nub on the carb base (for vacuum), it corrects iteslf.

I've done just about anyhting that can be done to a Mustang and have rebuilt several engines. Never seen this before.

Any ideas??? Thanks.

Starfury

Do you have aftermarket valve covers without baffles under the pcv and breather holes? Surefire way to get oil up into the PCV valve. Otherwise, could be a lot of blow-by causing the same thing.

brettc18

Stock covers. Baffles are in place. Any idea what would cause that much blow-by?

I left out the basics. It's a 289 in a '67 GTA fastback.

Starfury

Failing piston rings would cause excessive blow by=/ A quick compression test would tell you if that's the case or not.

It could also just be a stuck-open PCV valve, or the wrong valve for that engine. Hopefully this is the case.

brettc18

Thanks Ted.

It's a newly rebuilt engine and I'm confident I didn't break any rings. Good crosshatching too. I'll check compression to make sure, but I'll look a the PCV first. Thanks again.

BULLITT GT 390

I had the same thing it was a BadPCV valve!! it works fine now....

Aussie66Fastback

hi brett
my car does the same thing...motor is healthy, problem goes away if I disconnect the PCV and justput a breather cap in the hole.

to me the issue is with the amount of oil in the top end (ie inside the rocker covers) indicating poor draining back to the sump (which is unlikely on a ford, but a common problem on Aussie GM 5.0 engines) or something to do with the amount of vaccuum created by the carb/induction basically sucking oil out the PCV.

I am going to try looping the breather hose next to see if that stops it. please post again if you find anything else as its a pita kinda problem!

cheers
Ben

my77stang

you can hook up a simple oil catch can into your pcv system and keep that stuff from getting sucked back into your motor, or you can just run a vented system and say to hell with the hippies

Aussie66Fastback

my77 - any idea what actually causes the problem? is it vaccuum?

I was running a breather cap for the hippies, but the registration rules here required me to do the PCV back to the carb thing.

same road ***** prohibit a catch can