where to drill 21 stud intake for PCV?

[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]

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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.

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[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.

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