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Ross, my iron manifold has the 3/8"NPT port on the back of the carb flange like yours.
The hose is emission rated hose and I figured the heat shouldn't bother it as in normal duty it is conducting hot gasses back to the manifold anyway. Another thing I did that's not evident is drive an 1-1/4" expansion plug down into the hole where the road draft tube goes to plug it off. Then I installed the road draft tube and it looks stock.
Good catch on the gasket. I did try to put the manifold on only to realize the gasket has to go on before the PCV valve & associated hardware. Ad yes I do use guide studs. I have many on my truck from 1/4" up to 1".
I thought I'd throw this out there for anyone else who is contemplating adding PCV. I have a Canadian aluminum manifold off a big truck, that has an additional vacuum port that is much bigger than the one for wipers. I believe it was for vacuum-assisted brakes. It would be perfect for PCV. After comparing it to my cast iron manifold, I believe (have not yet confirmed) that an iron manifold could be drilled similarly.
It's drilled and tapped 3/8"-NPT, with holes drilled at an angle into each throttle bore at 3/16". It would be kind of hard to drill a shallow hole and tap it, almost certainly would require a bottoming tap. Maybe you could cut down a regular tap.
So, how did this work out running the pcv to this other 3/8 port next to the vacume port for.the wipers? I have this on my 8BA and would like.to do the pcv thing for my flatty. Will my wipers still work and do I have to do a significant amount of re tuning? Does adding a pcv help with any slight oil consumption .
I never ran vac wipers with my PCV, my truck came with electrics. It surely wouldn't make the wipers any better.
I have an air/fuel monitoring gauge in my truck and the affect on tuning with PCV is pretty predictable; it adds air that the carb isn't accounting for, so it runs a bit leaner, particularly at off-idle loads. Not enough to really feel, but the gauge catches it. Most of these trucks with stock carbs run pretty fat anyway, so being a little leaner doesn't hurt.
I highly recommend using a Fram PCV valve #FV306, it's just the right size.
Ok, easy enough to hook up. What does better crankcase breathing accomplish? Is it a environmental thing of perhaps just a little better oil control. My engine isn't new, I resurrected it from the junkyard. It runs plenty good. What caught my eye about this retrofit is one post talked about their flatty smoking/steaming out the filler cap and draft tube. I noticed that on mine as well and was hoping to rectify that issue . Perhaps maybe have a little better oil control through better ventilation , not to mention what it might do to prevent or help with sludge formation in an older engine.
I had pretty significant blow-by smoke out of the tailpipes and smoking out of the breather due to a clogged road draft tube. I replaced the tube with an aluminum plug I turned on the lathe with O-rings that was tapped for a PCV valve. I ran the hose to the carb base. This entirely eliminated the blow-by and reduced breather smoke by 75%.
Don't forget to replace the stock filler/breather cap with one that has a decent filter in it. I had one for an older 302, that had a rubber stem a little larger diameter than the filler tube. I was able to shave the rubber to fit.
What pcv valve did you use. I could turn one out as well.
I don't remember, but I believe it was for a similarly sized Chrysler motor. I went to AutoZ*** and looked at the PCV valves on display. That one had male thread and was for a V6 around 4.0L. I turned the blank to exactly fit the bore then added two grooves for the o rings to provide a friction fit. Center drilled the plug and threaded to match the PCV I purchased.
I sold the motor to a friend about 3 years ago when I put a 302 in my truck, and it is still working great.
10-02-2012, 11:49 PM
