What's the best setup for a non-stock crankcase ventilation system? I read an old GSCA article about welding pipes on the header collectors and connecting a hose to the manifold. Ive also heard about using a vacuum pump, but the car is mainly setup for street use (is the vacuum pump mainly for race setups???). I have mostly Kenne Bell products & a Holley 850. It still has the PCV in the back to the manifold and a hose from the passenger valve cover to the cleaner. I've read in some Holley articles that for performance setups the back vacuum port on the Holley should be blocked & the PCV valve removed. I am also currently working on a ram air system using the stage 2-hood scoop so I'm looking at using the filtered K&N breather on the valve cover.... BTW the PCV, grommet & hose look like original equipment, which is the main reason Im asking because it needs to be replaced. It seems that at higher RPMs its creating a vacuum leak causing the car to surge. Thanks, Ken
I don't think that the header system will work with mufflers. To much pressure in exhaust to make a vaccum at the valve covers. Tom
Thanks for the reply Tom... I also questioned that setup for street use. I suppose I will replace the original equipment and use the breathers in the valve cover and complete the ram air system that I'm currently working on. Thanks again, Ken
>>Any other opinion as to the application/validity of an electric pump? http://www.hardtail.com/techtips/vacuum-pumps.html >>Any downsides to the attached? Seems logical... and cost effective :grin: Thanks! John
John That looks like a great idea. My only question is do you plumb it to the brake booster or to intake?
Reynold, I'm thinking you pull from the valve cover breather or PVC location, to the pump, out to a catch can for race purposes. I guess you could also run in "series" to a header crankcase ventilation system and still have the headers burn off the gases/vapors and whatnot regardless of the exhaust system used (street) The "catch 22" here is that the pump as referenced in the previous link no longer seems available anywhere. Might be a good boneyard item though. SSBC has one in Jegs for 246.99. (brakes section). >> A bit too pricey for experimentation sake for me. John
The pipes and GULP valves on the collectors setup is called a "Vac-U-Pan" setup, and was designed for use with very low tension head-land ring sets, to evacuate as much pressure as possible that copuld get pushed past those low tension rings back into the cylinders. Head land riongs used gas ports in the piston tops to push them onto the cylinder walls for tension. Many drag racers use a specially modified stock type belt driven smog pump to eliminate excessive pressures in crankcases. Simple, easy to do, works well and doesn't have potential problems with electric components possible failures. Both of these methods are drag strip only. I built a 1260 cc Suzuki drag race engine a fellow ran on the street as well. Suzuki's have very poor crankcase venting, way too smell for even a stocker small engine. My regular tune-up special fix was to drill the 1/4 inch hose fitting at the breather to use a 5/6ths hose ID, and the heating and performance always became better. What I did for this particular 1260 was, took the stock breather hose to my usual 5/8th, then added two more 1/2 inch nipples and hoses into a catch can/vented container. ET immediately dropped 6/10ths of a second with NO other mods, we could now get the jetting down, engine temps dropped 40 degrees, we plowed forward from there. People don't tend to realize how much drag is possible from windage and air pressure resistance UNDER the piston tops. Add venting/hose diameter area for better crankcase/valley windage/air resistance reduction.
This sounds like a good idea, I did in the mean time replace the PCV valve, grommet & hose only to have the same surge problem which later turned out to be too light of a spring on the dist. advance... trying to pull it all in too quick. I put the stock springs back in for now. But since I replaced the crankcase ventilation system I would expect a slight vacuum on the valve cover opening which I don't see, maybe I've got another leak?
I wonder if a smog pump from a Buick V6 or late '70s 350 would work. I think the biggest problem would be getting a bracket to fit.
