Exhaust Header Gaskets
Thread Starter
Burning Brakes
Joined: Nov 2006
Posts: 893
Likes: 7
From: Orange Park Florida
Exhaust Header Gaskets
I have a small amount of oil blowing out of my valve cover breathers. I've tried breathers on both valve covers, a breather on the drivers side and a pcv valve on the pass side, and the most effective is the pcv on the drivers side with a breather on the pass side. Still, on a long drive I get a little oil blowback. I'm now in the process of installing sidepipes and new matching headers and have noticed that my current headers are square ported, the heads are square ported, but the PO used round ported gaskets (smaller than the ports) - thus blocking a good 1/4 inch diameter of exhaust flow out of each header pipe. Could this blockage be creating blowback or backflow through the engine, thus the valve covers, not to mention some HP loss? I am correcting this on my new exhaust system, but it seems the old gasket setup is creating a good bit of blockage or at least creating a choke.
Race Director
Joined: Apr 2000
Posts: 17,676
Likes: 201
From: Who says "Nothing is impossible" ? I've been doing nothing for years.
Does your PCV work ? and
how much vacuum do you have at idle ? and
do you drive with a lead foot ?
because at WOT there would be no vacuum so the PCV would be doing nothing. High speed full throttle runs on a performance motor you would probably get a little oil on the valve covers.
Make sure you PCV is working correctly, I never had a problem with my previous 550HP 406ci and my current 600HP 427ci small block after I figured out exactly how the PCV system works. I had cool looking billet aluminum PCV when I first put my 406ci and I would see oil mist on the valve covers. Turns out the expensive piece of crap billet PCV was very restricted. I went back to a normal $1.99 PCV and no more oil on the covers.
how much vacuum do you have at idle ? and
do you drive with a lead foot ?
because at WOT there would be no vacuum so the PCV would be doing nothing. High speed full throttle runs on a performance motor you would probably get a little oil on the valve covers.
Make sure you PCV is working correctly, I never had a problem with my previous 550HP 406ci and my current 600HP 427ci small block after I figured out exactly how the PCV system works. I had cool looking billet aluminum PCV when I first put my 406ci and I would see oil mist on the valve covers. Turns out the expensive piece of crap billet PCV was very restricted. I went back to a normal $1.99 PCV and no more oil on the covers.
Thread Starter
Burning Brakes
Joined: Nov 2006
Posts: 893
Likes: 7
From: Orange Park Florida
Thanks Motorhead, I will try it.
The current pcv is clean and working, but you raise an interesting point - maybe it is too restrictive. Also, vacuum at idle is where it should be. I'll try another pcv valve.
Thanks again
The current pcv is clean and working, but you raise an interesting point - maybe it is too restrictive. Also, vacuum at idle is where it should be. I'll try another pcv valve.
Thanks again
