Hello- I'm a new guy and fairly new to the engine world. I rebuilt a 401 nailhead for my 64 Buick Wildcat convertible and now I want to start doing a little customizing. This is a very basic question but, I joined this group in order to learn not teach so, here it is- I want to get a set of finned valve covers but I am running across a lot of covers that provide no hole for the pcv that my engine has as original. I see alot of rods out there that have pcv in them and a lot that don't have them. Does an aftermarket breather work just as well as the valve or should I stick with the valve as ususal? Do any of you buy covers and then have them machined to put a valve hole in them so you can use the pcv? The covers I was interested in are Moon finned covers but, the onley way I can make them work with the valve is to machine them and I can't see doing that after paying $200 bucks for them out of the box. Any suggestions would be great, thanks.
06-21-2003 07:52 PM
On a nailhead Buick you can place the pcv valve in the valley cover this will let you run the finned valve covers uncut.
06-21-2003 07:59 PM
I might not be much of help, but I pulled out a valve cover catalog, and a lot of them that aren't specialized have a caption beside them that say, "drill your own breather/filler cap openings". I have no experience Nailheads unfortunately, but I see some finned nailhead valvecovers on www.speedwaymotors.com; maybe they have the original pcv valve. I would definitely recommend keeping the motor as original as possible, though. Hope I've been some help.
06-21-2003 08:06 PM
You are confusing the function of the breather and the PCV valve. An engine bottom breathes in and out and you need some way to allow fresh, clean air in because there is occasionally a vacuum created which is what the breather is there for. It has an internal screen to keep out dirt but lets air in. More importantly, you need to have a place for pressure to escape because there is a lot of gasses entering the engine cavity from the combustion process. You don't want to depend on the breather to do this 'cause there is a fair amount of oil in the vapors and it really messes up the engine compartment. Until the environmental awareness came along in the 60s, engines just had a 'road tubeí; a 1 1/2" piece of tubing that connected to the engine lifter valley and extended down to below the engine near the road thus the name. Engine internal gasses were allowed to vent at will.
The PCV valve replaced the road tube and hooks the engine internals to the vacuum in the intake manifold and positively removes the vapors cleanly. Makeup air is let in by the breather so the 'air' inside the engine is much cleaner than the old days. Minor benefit is that the unburned hydrocarbons that used to be blown to the atmosphere are burned in your engine as fuel. PCVs are really a good idea all-round.
You have a few options. First, find a set of valve covers that have the necessary holes. Second, you might need to drill the valve covers for the valve. Put it in the valve cover opposite the breather so there is 'flow thru ventilation'. One final option is to put the PCV valve in the engine lifter valley if it has one separate from the intake manifold. Chevys donít' but early Chrysler hemis do - I don't know about Buicks.
06-21-2003 08:14 PM
Jesus, I knew I shouldn't have even tried that one. lol.
06-21-2003 09:00 PM
Hey guys-Thanks for the quick info. I'll keep looking for what I need but I pretty much made my mind up to keep the pcv and I am now glad I did. What threw me about breathers is the fact that I look at alot of engines at car shows and I see breathers on alot of them, sometimes on both valve covers. I guess not being familiar with the requirements of each engine doesn't help either. I did not know the valley cover could be an area to place the pcv, maybe I have to look harder at some of the iron out there. I have a factory breather on the oil fill cap which is opposite the pcv. Thanks again.
06-22-2003 07:43 AM
On my SBC 383 I wanted the pre'68 look but had a newer block. In one of the car mags (wish I could find it again), it showed how to drill and tap a hole in the rear of the block, into the lifter valley. You can then screw in a 90 degree fitting to clear the firewall and run a hose to the air cleaner (for intake air). I then ran a Corvette style oil filler tube with a screw-in PCV valve to the carb. Works like a charm.
06-22-2003 01:56 PM
Originally posted by MI2600 On my SBC 383 I wanted the pre'68 look but had a newer block. In one of the car mags (wish I could find it again), it showed how to drill and tap a hole in the rear of the block, into the lifter valley. You can then screw in a 90 degree fitting to clear the firewall and run a hose to the air cleaner (for intake air). I then ran a Corvette style oil filler tube with a screw-in PCV valve to the carb. Works like a charm.
Bingo! Classic hot rodder's solution to a task that "can't be done".