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Which PCV?

oldiron

Bronco Guru
Joined
Jul 21, 2005
Messages
1,032
I need some help on which pcv to use. There are a huge number of variations to choose from by application. This will need to be for my wifes '77...But it has an '86 ho engine, with a '70 2 bbl intake and '70 autolite 2100 carb and a c4.
This engine makes around 21 in hg at idle (if I remember correctly). The pcv I have in it now is a HUGE vacuum leak at idle (hard cold starts, off idle stumble, bogging etc) With this combination what would be a good /correct pcv valve (by application)?
With no pcv it idles like a dream..runs perfectly.
Any ideas?
Greg
 

DirtDonk

Contributor
Bronco Guru
Joined
Nov 3, 2003
Messages
47,355
I would agree with 904. What model is in there now? Do you know if it was for the '77?

I wanted a 90° fitting so ended up with a '72 Chevy 350, non-LT1 model I believe.
Worked great.
The one I picked from a '74 Granada 302 was just like you describe yours to be. A huge vacuum leak.
The stock '71 302 worked fine, but had that vertical fitment rather than the 90, so I kept the GM unit.

Then again, there's always this... Bitchin Expensive PCV Valve

Paul
 

blubuckaroo

Grease Monkey
Joined
Jun 11, 2007
Messages
11,795
Loc.
Ridgefield WA
There's a lot more to it than just the angle of the nipple.
Since it's just a metered vacuum leak at cruise and full throttle, your jets may need changing if you change the flow of the valve.
 

DirtDonk

Contributor
Bronco Guru
Joined
Nov 3, 2003
Messages
47,355
That's why I tried six different PCV valves until I found the one that worked the best (35 years ago) testing each one on the vehicle to see which was the best match to the original.
For me it was ALL about the angle of the nipple. I knew there were differences or there would not be 48,001 part numbers all looking similar and fitting just fine. But I wanted one with a 90 degree nipple to clean up my hose routing.

The one with the most flow/leanest mixture was the one I kept in my tool box under the hood to swap out every time I got above 4,000 ft elevation on trips to the Sierras.
Saved me a lot of grief running rich at altitude, and hassle changing jets for just a weekend trip.

But then came fuel-injection... Problem solved!

Paul
 
OP
OP
oldiron

oldiron

Bronco Guru
Joined
Jul 21, 2005
Messages
1,032
Wonder why nobody thought of something like this years ago?
Very cool.
 

DirtDonk

Contributor
Bronco Guru
Joined
Nov 3, 2003
Messages
47,355
I wonder how long the company has been making the "tunable" version in the link? It's pretty cool and, even at that price, I'm still tempted to try one even though mine are all working well with the engines they're installed on.

Paul
 

Lawndart

Sr. Member
Joined
Nov 23, 2014
Messages
836
Loc.
66030
I played around for a while trying to fine a good PVC valve.
I finally went with the Bitchin Expensive PCV Valve (aka M/E Wagner DF-17 Dual Flow PCV Valve).
Still happy I did.
 

vintage bronco

Sr. Member
Joined
Feb 8, 2010
Messages
850
I wonder how long the company has been making the "tunable" version in the link? It's pretty cool and, even at that price, I'm still tempted to try one even though mine are all working well with the engines they're installed on.

Paul

Paul
You will not be sorry you did it they offer your money back if not happy but you wish you done it long ago.
 
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