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Manifold internal distribution tubes

jimct

Contributing Member
Pulled the end plates off my 3

Pulled the end plates off my 318 end discharge manifolds and found no internal copper distribution tubes. From what I've read these tubes provide more complete water circulation in the manifolds and reduce steaming & hot spots. They appear to be just flared copper pipe so I should be able to fabricate them myself. I'd have to change the water feed into the manifolds to the lowest point aft where the pipe plug drains are. Any thoughts and/or experience with the tubes?
 
Jim:
You may not need or want


Jim:
You may not need or want those tubes. It depends on your setup. Raw water vs. fresh. Front water feed or rear. The tubes drain raw water from near the high end of the manifold so there is always water in the manifold. I have the tubes because of the angle of my engines and they are raw water cooled. Some fresh water cooled 318's circulate antifreeze through the manifolds as well as the engine. There are 8 different diagrams for engine/manifold cooling setups in my chrysler manual. If you need a copy let me know.
 
Thanks for the offer Peter &am

Thanks for the offer Peter & I'll take you up on it.

Would like to see if my plumbing is set up as it should be. My manual shows very little. Be nice to be able to plumb the FW loop through the manifolds. My concern would be if the heat exchanger (standard issue) has the capability of pulling the extra BTU's out.
 
"Peter:

I have raw water co


"Peter:

I have raw water cooled 360s. Accidentally left out the copper tube, and that manifold runs the coolest.

Note: On mine, the water comes in the FRONT of the maifolds."
 
"Fastjeff, the tubed manifold,

"Fastjeff, the tubed manifold, fed from the front of the manifold, should run hotter since the cooling water is "short circuited". Water is entering at the front of the manifold and is, in effect, exiting at the front.

Peter, my engine's at a fair angle and I'm hoping the tubes will cut the steam some. After pulling the manifolds, risers & elbows I found the manifolds in good shape but the risers/elbows about done for. Tx again for the .pdf's.

I looked into the heat exchanger for fresh water cooling the manifolds. $500+... mounts aft over the transmission. My engine's mounted under the ctr. console so I doubt it would fit. A remote location might work, but where? Be a nice set-up to have though..."
 
"Jim:

The OSCO tech guy ref


"Jim:

The OSCO tech guy refused to believe my manifolds cool properly with the tubes in place and the water coming in the front. (The water should come in low and in the rear, flow up and forward, then sneak out the slots in the tube--that are in front). But it DOES work. My temp gun says the manifolds are running the same temperatures throughout, with the one that I left the tube out running the coolest.

Weird, hun?

Jeff"
 
"The copper tube doesn't r

"The copper tube doesn't reach all the way to the front of the manifold. So when the water enters the manifold at the front, some of it is drawn out at the tube but some misses the tube and circulates in the manifold and then gets drawn out through the tube.
As long as you don't develop an air bubble in the manifold without the tube........."
 
"Sounds like a little thermo-s

"Sounds like a little thermo-syphon action is helping with the cooling... hot water rising and exiting at the highest point. My '49 Farmall Cub tractor cools the same way. No water pump; convection alone circulates water through the engine & radiator. Hotter the engine gets, the more rapid the circulation through the radiator."
 
"Got most of the items for the

"Got most of the items for the manifold re-plumbing. While I'm at it and the bolts are accessible, I'm pulling the valve covers to clean, de-rust and re-paint along with the manifolds & new risers/elbows. The various manifold plugs & drains will be replaced and anti-seized.

Two Questions:
When remounting the manifolds should gasket sealer be used on the gaskets?

Do the manifolds take any pencil zincs?"
 
"No and no. Be damn sure ALL o

"No and no. Be damn sure ALL old gasket material has been removed, and that you follow professional bolting techniques, and all will be well:

1. All threads are cleaned

2. Use at least Grade 5 NEW bolts

3. Lube the threads with oil or anti-seize

4. Snug, then tighten, a little at a time using the cross tightening method

5. Retighten after everything has warmed up.

Jeff"
 
"OK, thanks Jeff.

BTW, I se


"OK, thanks Jeff.

BTW, I see two areas at the base of my Edelbrock 600 for vacuum connections. One between the jets, other at the back of the carb. Any difference which one PCV connects to?"
 
"P.C.V. goes to the fitting at

"P.C.V. goes to the fitting at the front of the carb, between the idle speed mixture screws"
 
Finished buttoning up everythi

Finished buttoning up everything on the engine & fired it up on the trailer. BIG difference with the re-routed manifold cooling flow. Manifolds are now barely warm to the touch and zero steam from the exhaust. No leaks and all's well. One more go-around with the torque wrench and we're done. Nice when things work out as planned. Thanks for to all for the assist.
 
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