Quote:
Originally Posted by Bored&Stroked
If you put an early manifold on it, then you should think about welding up the TOP of the vent tube that pulls air from the crankcase and delivers it to the bottom of the manilfold - and out the road-draft tube on a stock 49-53. Then you can mount a PVC into the top side of the tube so you can have a vacuum system pulling the crankcase fumes and water vapor from the crankcase. This encourages the inlet air (from the back of the manifold) to be pulled down into the crankcase and pulled up the tube that you just modified. There are a few posts about this technique and the associated mods to the tube, to the bottom of the manifold, etc..
Personally, I do not like crankcase breathers bolted to the oil pan - every one I've ever done or seen (unless really tall - like a long filler tube) will cause oil to drip down the whole undercarriage of your car as well as your garage floor. The vapors coming out of the oil pan will carry oil mist - and you'll have oil on the outside of the breather . . . going places you don't like. Also, there is nothing on a pan breather to actually PULL the air out the breather --- like the original road-draft tube did . . . so you need a PVC to replace that original concept if you're not going to run it.
Best of luck!
|
B&S is correct on ALL counts above. The PCV valve must draw from the modified (capped-off), removable road draft tube stub at the front of the valve chamber, 8BA. That can clearly be seen on the drawing I posted above by the UP-flowing arrows toward the front of engine. The idea is for fresh air to enter the breather tube at rear on an EARLY intake manifold, which is drawn down into the lower crankcase and exiting into that forward, up-flowing tube. One more important function is to relieve internal crankcase pressure generated from blow-by. If not relieved, you WILL have oil leaks everywhere. This arrangement accomplishes the fumes/ventilation going from one end of engine to the other.....cross ventilation. Your PCV valve, and ultimately the vacuum source, will pull the vapors from that tube, hidden by the intake manifold. We're doing a system based on the same theory, but with the PCV valve mounted just inside and below the rear breather tube for future service/changing without the need to remove manifold. There will be one simple, polished copper tube exiting the side of a custom breather tube, plumbed to manifold vacuum fitting between the 2 x 2s on a Thickstun PM7. NOTE: MOST PCV valves should NOT be mounted any way other than vertically! Pictures and part numbers and details to come at a future date. Teaser picture below! DD
