where to drill 21 stud intake for PCV?

[mumpsimus]

I saved a photo from an old forum thread that I can no longer find. It shows a tiny 1/4" hole drilled into the intake manifold on the passenger side beside the generator. But the PCV that everybody recommended has a rubber grommet that needs a very large 1" diameter hole (Standard V261 PCV, grommet HELP 42322). There isn't a space on the side of the manifold large enough to drill a 1" hole. Anybody out there with a PCV on their 21 stud motor, can you please let me know where you drilled the hole for the PCV and grommet?

The other end of the rubber hose was supposed to go to a 1/4NPT fitting drilled into the intake runner under the carb. But there appears to be a hot air jacket all the way around the vertical intake channels. Do you instead drill into one of the horizontal channels that feeds a pair of cylinders?

Sorry if this has been covered before. I've found lots of forum posts on PCVs in the later motors, but can no longer find that one thread that had info on how to install a PCV in an early 21 stud.

[mumpsimus]

This was the image that I found a while ago and saved with the tiny hole drilled.

[mumpsimus]

https://ibb.co/pntH6Lq

[JSeery]

To get the photo in the thread.

[qmdv]

why have a pcv to begin with

[JSeery]

Sponsored Links (Register now to hide all advertisements)

Some don"t like the smell or oil vapor of the road draft system. Ford used a PCV system in some enclosed environments such as military applications. I'm not a PCV fan, but a lot of folks are.

[blucar]

The Positive Crankcase Valve (PCV) is the best addition ever applied to an engine. The PCV removed 95% of the emissions discharged into the air, and it solved a lot of problems that the common engines had prior to 1963.
The road draft tube type of engine ventilation did not work well when the vehicle was stationary, sitting at a stop light idling, etc.
I have made it a habit to install a PCV system to every old car I have owned since the early seventies.

[Jack E/NJ]

https://www.fordbarn.com/forum/showp...2&postcount=13

Jack E/NJ

[mumpsimus]

I’m still hoping to hear from somebody who can say where to mount a PCV on a 21 stud motor. Maybe I need to buy a different valve, one that doesn’t require a 1.0” diameter hole in the manifold near the generator?


Sent from my iPhone using Tapatalk

[JSeery]

There are PCV valves with pipe threads.

[mumpsimus]

Originally Posted by JSeery

There are PCV valves with pipe threads.

I think that’s the solution. The grommet type one that was recommended is just too big. I’ll find a valve with 1/4NPT threads. That should be easy to fit beside the generator.


Sent from my iPhone using Tapatalk

[A bones]

Originally Posted by qmdv

why have a pcv to begin with

The vapors and oil residue coming out of multiple motors, think metropolitan highways + byways, were very very toxic. Not to mention increased skidding issues with the arrival of lite rains. In my youthful, Philly, eyes and heart there was no way the GROWTH of motor travel could continue.

Thankfully the PCV systems changed all of that.!!
Respects paid to paper filters and electronic fuel injection.

.

[cajunfirehawk]

In some cases with an electric cooling fan the oil vapors (smoke) are not seen too much, IMHO

[Talkwrench]

Drill one in the front of the manifold. Find a grommet, drill to suit and PCV of correct size to suit the engine capacity. . You may need to come up with a baffle on the inside if you think it can suck oil..[?] . Hole under the carb drill or use a vacuum plate. Block off the draft tube. Make sure it can still and breath from the vent cap.

[JSeery]

From another thread: "FV 100 FRAM This is the one that should thread into the intake." 36Coupe

[B-O-B]

Try the HAMB lots of info there. I am like JSeery & do not use one.

[flatheadmurre]

I don´t do PCV unless there is a seal on the crankshaft.
Using the slinger and PCV is not a good solution in my book since it will draw in dirt that way....

[JSeery]

I'm with flatheadmurre, a PCV system on a 21 stud engine with the slinger rear seal is a bad idea. You are pulling unfiltered air into the crankcase and the bellhousing/clutch area has a lot of undesirable stuff in it.

[Talkwrench]

Originally Posted by flatheadmurre

I don´t do PCV unless there is a seal on the crankshaft.
Using the slinger and PCV is not a good solution in my book since it will draw in dirt that way....

Good point..

[Jack E/NJ]

Even with the pan vent blocked, PCV probably won't pull enough vacuum to worry about this issue. Forget a PCV valve anyway. Simply entrain the crankcase stink into the air cleaner with a hose from chrysler-style oil filler cap. Jack E/NJ

[JSeery]

There would be little reason for a PCV system if it didn't draw the vapors out of the crankcase. If it is drawing out of the crankcase it will pull air in around the real seal.

[Jack E/NJ]

>>>If it is drawing out of the crankcase it will pull air in around the real seal.>>>

Sure. Just like the pan vent does. Not much more. This is lo vac stink entrainment in the air cleaner draft. Like road draft. Not hi manifold vac. Jack E/NJ

[JSeery]

A PCV works off of manifold vacuum, maybe we are talking different systems? Think you are referring to a passive system using air filter air flow. This post was about PCV using manifold vacuum.

[Jack E/NJ]

Yep. That's why I suggested that Mumpsimus forget the valve altogether. Just go passive entrainment in the engine compartment if cabin stink is the problem. Jack E/NJ

[mumpsimus]

Originally Posted by Talkwrench

Drill one in the front of the manifold. Find a grommet, drill to suit and PCV of correct size to suit the engine capacity. . You may need to come up with a baffle on the inside if you think it can suck oil..[?] . Hole under the carb drill or use a vacuum plate. Block off the draft tube. Make sure it can still and breath from the vent cap.

thanks Talkwrench. The issue is that the recommended PCV requires a gigantic 1" diameter hole for its grommet and there is no place on a 21 stud intake big enough to drill a hole that large. But I found a different PCV with 3/8NPT threads which are much smaller than 1" and I'll drill and tap a hole in the manifold for it.

Under the carb, my manifold looks different than the one in your pic, and there isn't a place to drill it, so I bought a vacuum plate with a 1/4NPT hole in it already. All that I have to do now is block off the draft tube with a freeze plug and I'm ready.

If I can figure out how to post images, I'll reply later with images of how my parts fit together.

[Talkwrench]

Sponsored Links (Register now to hide all advertisements)

Yes its a big hole I managed to do it no problem. But as the boys pointed out you will suck air from the labyrinth seal and it can get grubby in there especially if the can is missing from over the bendix. Im sure if you not driving daily it will be ok .

[JSeery]

Originally Posted by Jack E/NJ

Yep. That's why I suggested that Mumpsimus forget the valve altogether. Just go passive entrainment in the engine compartment if cabin stink is the problem. Jack E/NJ

Sounds like were are the same page. Just PVC is a bad idea in early 21 stud blocks. Guess my question would be why would you want to install a system on an engine that increases the contaminates in the oil?

[msstring]

So, I am in the process of having my 8BA rebuilt. Is there a different main seal I can use to be able to do a PCV? I was thinking of blocking the draw tube at the open end and tapping the indeed to the PCV to the side of that. Thinking this will provide the baffle effect. I think I have a threaded port right under the carb that I can put the suction end in. But, now you guys are blowing up my thought process with this seal business. This truck came from Nebraska gravel roads and inside it had a LOT of sand. Would like to keep it cleaner.

Sent from my LM-G710VM using Tapatalk

[JSeery]

None of that discussion applies to a 59ab or 8ba, they have a rear main seal.

[msstring]

Originally Posted by JSeery

None of that discussion applies to a 59ab or 8ba, they have a rear main seal.

Thanks, that's good to know.

Sent from my LM-G710VM using Tapatalk