Been searching the hamb for awhile now and can't find the info im looking for. my simple question is.......... I'm running an older intake without a road draft tube, I don't want to install a PCV system right now. I'm thinking I can just cut the crankcase tube down an inch before it meets the intake, let it vent into the vally and run a breather where the fuel pump is supposed to be. Will this work?
You're not going to have any ventilation if you do that, only a pressure escape. There has to be a way for air to be drawn into the engine, then pulled out. A pcv system is the best way to do this on a late engine with an early intake. Capping off the tube, adding a pcv to it, and plumbing into the bottom of the intake is not that hard to do, and your engine will thank you for it.
The arrows show the air flow that is supposed to take place with the original 8BA. Without this or a PCV valve you will end up with a gunked up nasty flathead. It's not just a vent.
How do you guys feel about adding one of those engine breathers from Offenhauser or Moon on the side of the oil pan? Do they still make a mess?
I have an 8ba without a road draft tube as well and a breather where the fuel pump used to be. Could this be why it smokes so bad. Was thinking that the rings had not seated and that I was going to have to tear it apart and re ring it. Thanks Greenracer
Why go through all the work and bother to try to get away from installing a PVC when its simple, fast and cheap to install. The best thing you could do for a flathead.
It has a major role in removing water vapors and various nasties that turn into water and gunk in an engine. The draft tube was the OUT for the venting, so its hole is perfect as the spot for PCV, but since you don't have that hole this is a natural for the under-manifold PCV that has been posted on here...that kills 2 problems. 1. It lets you tap into both sides of manifold, which is hard to do up top on most multiple manifolds. 2. It lets you hang the suction side over that tube in the valley. On early flatheads, the factory plugged the lower outlet on pan and ran the line from an external PCV through manifold right over that tube on the military engines that got PCV.
I have been running my engine this way for about 18 years now and I show absolutely no sign of any sludge build up. This engine is as clean as the day I built it. I always meant to put a PCV valve on but being the procrastinator I am, it never got done. I guess I credit today's superior oils to the lack of any sludge problems.
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