How to use PCV valve w Tri Power?

[AnthonyG]

I run Tri power on an 8BA. Had pvc valve pulling crankcase fumes from crankcase vent tube to vacuum fitting on intake manifold. I removed for unrelated issue then rethought putting on the same way thinking the crankcase fumes s/b filtered before re-entering directly into the engine / vacuum port. Normally on stock 2 or 4 barrel an air cleaner would receive the fumes on filter side of carb. Typical Tri power air cleaners have no port for pcv valve tube. How do others set up pvc w Tri power? Does anyone make pcv valve filter to use on vacuum side of pvc valve tube?

[vilanar]

The tube from filter to valve cover on OHV engine is intake side of the PCV system , blow by fumes are sucked through PCV valve straight to intake , usually there is that large tube underneath throttle plates on 4 barrel carburetors.
On flathead incoming air is filtered by filter inside the oil cap . In my 3x2 I made a port in the base of middle carb. Actually there is separate spacer witch works as a heat barrier at the same time.
If you meant oil separator system , don't know about those.
Hope I didn't understood your question wrong.

[51 MERC-CT]

Do you in fact have an 8BA tri power manifold configured like this?

[JSeery]

As Vilanar posted, the air filter connection is the intake to an OEM PCV system.

[51 MERC-CT]

On the 8BA system a Mopar oil filler/filter cap can be used with a tube to the outer plenum of the carburetor air filter assy. (out side of the carb. filter)

[AnthonyG]

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as both Vilanar & 51MERC-Ct indicate I have been using a threaded vacuum port in center base on intake under center carb & will probably go back to that setup. Just thought I might need a filter on it prior to entering the intake. I like the idea of the pcv tube port on the Mopar oil filler cap.
Thx all

[JSeery]

You want the filter prior to entering the crankcase. Drawing dirty/dusty air into the crankcase is not a good plan long-term.

[Pete F.]

What PCV valves are you guys running


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[51 MERC-CT]

Originally Posted by Pete F.

What PCV valves are you guys running


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My set up uses a (NAPA- CRB 29207 valve) and a (NAPA- CRB 29116 grommet)

[Krylon32]

I had Bob at Baxter Ford parts do several 8BA manifolds with either 2 or 3 carbs and he always put a freeze plug with a pcv valve in the road draft tube hole with hard line around to the right side tapped into the intake. Never heard back from any of my customers that they had a problem

[rich b]

Seems to me, the "vacuum leak" that is the line from the PCV valve should be divided equally between both plains of the manifold like it is on OEM applications. so as not to slightly "lean out" half the engine.

Some of the old aftermarket vacuum plates are made this way; but some are not; need to look at the throttle bores to see.

So, in my way of thinking, a properly made under carb vacuum plate would be preferable to porting into the left side of the intake.

Or, am I all wrong?

[V8 Bob]

Originally Posted by rich b

Seems to me, the "vacuum leak" that is the line from the PCV valve should be divided equally between both plains of the manifold like it is on OEM applications. so as not to slightly "lean out" half the engine.

Some of the old aftermarket vacuum plates are made this way; but some are not; need to look at the throttle bores to see.

So, in my way of thinking, a properly made under carb vacuum plate would be preferable to porting into the left side of the intake.

Or, am I all wrong?

You're correct that both planes (of a dual plane intake) should "pull" on a pcv. An under carb plate, or port in the open plenum is best, but a port into the side of a dual plane will work if you extend the drilled hole (1'4" or so) into the other plane. That's what I did with the Edelbrock dual intake on my '51.
The tri-power Navarro intake in the '32 has the hidden pcv plumbed to each plane under the intake.

[Bored&Stroked]

RE: 39-48 Flatheads: One thing for folks to remember is that is you're running a 39-48 style flathead, the above setup is not all that you need to do - the air-flow path is completely different on the earlier engines and to get it all working correctly, you also need to weld up the triangular road-draft vent on the oil pan itself - and/or weld-up the down-draft tube that taps into the front of the block and delivers the crankcase gases to that little triangular vent in the pan.

Lastly, if you're going to run a late 49-53 manifold, then the fresh air entry port (49-53 new oil and vent tube) - needs to be plugged and the rear of the manifold needs to act as the oil and fresh air entry location (like the earlier manifolds).

Also, you need to run the fuel-pump "vent baffle" that goes between the back of the intake and the valley in the block. Many guys threw these out back in the day and I frequently see them missing in engines. This baffle directs the external air that is flowing into the valley area - DOWN into the crankcase area.

Good luck gang!
B&S