Thanks Daniel,I will keep that in mind.I have found one from 55birdman who has had it for years off his own car.I am sure its better than many of the ones that have been passed around.So to make this PCV system work I add a PCV valve and grommet to fit the existing hole and then plug the hose into the vacuum fitting on carb.Remove and plug the road draft tube.Is there something else to check while the cover is off?A couple of previous threads mention something about 2 small holes to check and be sure they are open.Don't understand what is being discussed.Any other input appreciated.Mark

  

Hit up the local VW speed shop and pick up a VW fuel pump block off plate, cost about $10.00 or so. Fits right over the road draft hole. Use the road draft hardware though. If you park in the garage you might notice after a while that the smell of the road draft tube is not there any more. Gerry 

Lake Forest California  5th inf 77 Armor Div. VN 68/69

If you put your town and state in your signature

help might be closer than you think.

Mark,



You did not specify carb.#, but "Murphys' Law" usually proves most assumptions are wrong. If your new manifold has a vacuum port, why not use IT, and block the carb port if there is any doubt?



Also, be advised that an unrestricted PCV air source can sometimes act like a vacuum leak, and cause a lean-running condition. I had to install a 1/16" restrictor in the PCV hose on my 292 to keep it from plnging, even though the new valve came from a Y-Block-specific catalog source.

6 VOLTS/POS. GRD. NW INDIANA

Unless the mainfold vac port is in a location that feeds all cylinders equaly you will have better results using the pcv inlet provided on the carb. It's centraly located and will feed the extra flow ftom the pcv valve to all cylinders and not just cause a lean condition in a few cylinders.

The other poster who added the restriction to stop the pinging, could you have a few lean cylinders from an unbalanced pcv feed??   If not I would rather rejet the carb then restrict the pcv system, why have it if you are not going to let it flow as the valve wants it to. By restricting the line your pcv flow at low vac conditions will be low causing the crankcase pressure to vent out the breather cap pulling oil with it.

Thanks for the input.The carb is a 390cfm Holley which has a vacuum fitting on it for PCV hookup.The other manifold vacuum fitting is the one on the backend where you would hookup the vacuum accessories.Should I plug the PCV into that rather than the carb?I was just  going to plug that one.Good to know about the VW pump blockoff.Thanks all.Regards Mark

  

Mark, just sent you an e-mail or private message through the system...

Dan

Daniel Jessup

Lancaster, California

aka "The Hot Rod Reverend"
check out the 1955 Ford Fairlane build at www.hotrodreverend.com

I also have the 390 carb and used the fitting on the carb, the fitting on the manifold is more direct to the rear cylinders and the added flow from the pcv system may cause a lean condition in the rear cylinders. My 390 is on a 312 engine and required no rejeting for the pvc.

The VW block off plate is a great idea, I was lucky and had a TBird block off plate, the bird (55-56-57) had a rear road draft tube (the valley cover you are looking for) but the block had a side opening for a road draft canister so the factory installed a block off plate.

Kevin,



PCV vac. source is ported spacer under the carb. Unless breather cap is restricted, oil won't pump out, even after hard/high rpm running.



Still plenty of vacuum pull through the filler tube at idle with PCV restrictor. Wouldn't main jet change be moot at low manifold vac.? Back in the day, jets were sized by reading the plugs after a full speed pull (throttle wide open=low vacuum).

6 VOLTS/POS. GRD. NW INDIANA

The PCV port on the holley is straight manifold vac, it's not ported. While you may have plenty of flow at idle (at high Vac) I feel that at wide open throtle when vac is low (and blow by would be higher) the restrictor will cause the crankcase vapors to back out the filler cap. The PCV valve is spring loaded and opens up under low vac conditions to keep the PCV flow reletivly constant under all vac conditons. A restrictor will flow a lower flow under low vac conditions.

I agree reading plugs is the way to go, they should also all be even. Using the manifold rear port will result in uneven fuel mixtures between front and rear cylinders as the PCV flow will dilute the mixture to the rear cylinders.

Hello Kevink1955,Do you happen to know what part#PCV you used or the application for it?I see your discussion regarding restrictors etc but if you think about  it there are many different PCV valves depending on application.Part of the differences would be spring pressure and I would think internal passage size depending on flow requirements for a particular engine.Does this not qualify as a restrictor?If someone is using one with too much airflow and a restrictor corrects the problem isnt it the same thing as using the correct PCV valve?Just my opinion.RegardsMark