I'm attempting to aquire a VIN number from the the great state of Pennsylvania for a specially constructed vehicle. Its a '30-'31 Model A reproduction with a SBC. The fan shroud I could understand, the back up lights were a little harder and now I have to have a PVC system. I've read all the posts and understand the theory. Now I need to know how to do it. The only vacumn port feeds the TH350. I have access into the valve cover. HELP
PVC is poly vinyl chloride. Don't think you got one of them!! PCV is positive crankcase ventilation. Looking at your pics it looks like you have a hose going from a brass fitting on the rear of you carb back to the rear of the block (the picture isn't to detailed. Anyway, I belive that may be you pcv system. It is the early GM type that doesn't use the valve cover. Todd
There are a couple of ways you could do this.. The easiest would be to replace your brass fitting with a dual fitting and run the pcv from valve cover to that.. You could also put an 1" spacer under one of your carbs and put a vacuumn port there.. Either way you'll need a breather port in the other valve cover to get air in.. Hope this helps........
Thanks scrap metal. The other valve cover has a breather for air to enter. I thought tee'ing into the vacumn that close to the transmission vacumn line could affect the shifting. Thanks
I can't see your picture very well. For the transmission you need a line pulling your vacuum, on mine I need around 10 to get a decent signal, if you have anything that will pull a decent vacuum that is not dedicated to timing it should work for the trans. The brake booster would be a different story. If you don't need vac for the brakes, run a pcv valve from the port on the valve cover to the open vac port. On the other Valve cover place a breather. The air flow will go from the breather thru the engine and into the combustion part of the engine evacuating the gases and burning them. Without this cross flow you build pressures and emit hydro carbons from the breathers, you also trap water vapors and corrosives in the blocks oiled systems. It's a good system to have emissions or not.
What if you just fake one in there, and yank it after you get your VIN? Put a PCV valve in the valve cover, and run the hose some where to a hidden spot under the carb. Will they pay that close attention?
If he runs it at the test place it will be blowing out the breathers and condensating on the valve cover. The test guy would have to be really dense or a total newbie to be fooled.
The port shown in the 2 pics are off of the rear #5 & #8 runner, don't use that port. Will make those 2 cly. go lean and engine will run like it has a vacuum leak. Use scrapmetal's second option, this will even out the vacuum feed to all cly's. Then just fatten up the idle mixture slightly. Added......I would do a 1" spacer under the carb adapter rather than just under the 1 carb. Or if you feel up to the job, drill the adapter at the rear dead center and tap 1/4" NPT.
Not to hijack the thread, but in short. Running breathers on both my covers. No pcv. Running trans hose to rear port on manifold. Brake booster to where pcv would normally go, under carb (600 holley vac 2nd's). After reading numerous posts elsewhere, got a little confused, changed trans and booster to twin adapter on rear manifold port, brakes seem a lot better, but now nothing going to pcv port under carb. With it open, engine idles up a lot higher and port is sucking like a demon. Do I just plug that port until I get a pcv valve sorted. I'll change 1 breather for a cap to use pcv and hose.
Just go ahead and put the pcv in.. You can't run with that port open.. You could plug it, but just get the pcv and put it in the valve cover and hose it to that port.. NOW.....
Nope, just put a pcv on the one valve cover and run the hose from the Pcv to the vac source. Your engine is now ventilated. Let me know if you are still confused and I will take a picture of my rusty heap to show you how I ran my PCV.
The Jalopy Journal
