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PCV valve question

JWMcCrary

Contributor
Bronco Guru
Joined
Oct 14, 2004
Messages
5,001
I'm getting a little smoke under load with 3/4 throttle, that's the only time you get an ounce out of it, obviously a worn engine will do that but I'm 99% certain that isn't the problem here. I think the PCV is letting oil get sucked out the valve cover into the intake. SO, need to get a new one. I'm not sure I've ever had the correct one on it. Does engine specs matter? Motor is a 70s galaxie 351w that was stroked (395), aluminum heads, comp cam, Holley fuel injection etc. Do I need to ask for a PCV for just a stock 351w or for it to be correct does it need to be specific to engine setup? Seems like a novice question but it's something I've never paid much attention to.
 

DirtDonk

Contributor
Bronco Guru
Joined
Nov 3, 2003
Messages
47,346
Yes, they are specific, and probably should be chosen by all the mods done to the engine after the fact. But who knows what that would mean? Nobody I know, and I've never seen a "conversion list" of characteristics to look for in a PCV valve when choosing.

So my fall-back has always been the same. Use the one specified in the original motor, in the original application. In your case, a '70's Galaxie.
I've done some experimentation though, where I found a smog-era 302 valve from a Granada would not work in my '71 Bronco 302 because it let way too much air in. They're always sucking a lot of air when they're sucking, but apparently there can be quite a difference.

To get the feature I wanted (90° 3/8" hose fitting) on the same size valve as stock, I chose one from a '71 Corvette with 350 because it was more likely to be a higher compression, less smogged engine application.
That one worked, as far as I could tell, just as well as the original one from the Bronco. No jetting or adjustments were necessary when I used that one. Unlike the one from the Granada 302 which gave me basically a huge vacuum leak that I would have had to re-jet richer and use more squirter to compensate for.

Instead, and you may have heard me talk about this before, that Granada valve stayed in my under-hood tool box and got installed every time I went up into the mountains above 4000' or so.
The goal was to take advantage of that "controlled vacuum leak" and not lose so much pep going up the hills at high altitude without having to re-jet the carb leaner for trips to the hills.
Worked great!
Between that valve and my MSD "Adjustable Timing" Dura Spark module (adjustable on the fly from a dash knob) my trips to the mountains were pretty uneventful after that.
No substitute for EFI or turbo-charging of course, but did the trick back then.

So anyway, not sure what parameters to use in your case. But the good news is that at least experimenting is cheap!
With an engine like that, maybe a mid-sixties high-compression muscle car valve?

Good luck.

Paul
 

Mikey

Bronco Guru
Joined
Aug 15, 2001
Messages
1,477
When I put a 4V, open element air cleaner, aluminum intake, headers and dual exhaust, I ordered a PCV for 65 Mustang Hi Po 289.....did the same for my 68 Cougar with similar mods. Seemed to work fine. I have the PCV plumbed to base of my Holley and the oil filler cap in the valve cover is a breather type. My set up sorta matches the old Hi Po 289 Mustang.
 

blubuckaroo

Grease Monkey
Joined
Jun 11, 2007
Messages
11,795
Loc.
Ridgefield WA
The blowby from work rings will increase the oil consumption through the PCV valve as well. Is there oil around the PCV said inlet in the air cleaner?
Have you considered your valve guides? You could do a compression test to find out thee health of the motor.
 

pcf_mark

Bronco Guru
Joined
Jun 11, 2010
Messages
3,574
I use one off the 70 Corvette LT-1- it is a 350 CID / 370 HP engine that revs and makes plenty of power everywhere. My go-to PCV.
 
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