Intake Manifold Question

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I haven't read through all the posts but. With the passage blocked off at the intake make sure your heat riser valve is open or removed and that it stays open. Wire it open if you don't remove it. If you have headers, no problem.
 
Toolman,
Yes, I removed the heat riser butterfly valve on the right exhaust manifold and have dual exhaust. I also plan on using a 1/4" insulator between the intake manifold and the Carter 4 barrel with electric choke, on my 273. I've ordered an intake manifold gasket with stainless between fiber but I think adding thin stainless plates over the exhaust port on top of the heads is still a good idea. Most of my driving is in S. CA, but I do plan to travel.
 
Richard Sweet said:
Toolman,
Yes, I removed the heat riser butterfly valve on the right exhaust manifold and have dual exhaust. I also plan on using a 1/4" insulator between the intake manifold and the Carter 4 barrel with electric choke, on my 273. I've ordered an intake manifold gasket with stainless between fiber but I think adding thin stainless plates over the exhaust port on top of the heads is still a good idea. Most of my driving is in S. CA, but I do plan to travel.
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Sounds like you're on the right track.
 
I was just thinking on this issue after reading this thread. Does anyone know what temperatures we get at the area of the head/manifold interface?

Left is a dual quad on top of which I plan to be running carbs with annular boosters which will give me smaller droplet size, and I _think_ that will allow the fuel to more readily soak up heat (greater surface are to volume ratio with smaller droplet size). Do I even want that though? I would rather avoid all the heat I can going into the intake manifold.

I was considering having those ports on the manifold welded up. I was also considering blocking off those passages with some JB Weld high temp putty. I'm gonna try the welding option first.


IMG_20200412_0841286[1].jpg


jbweldcom_575240777.jpg



You gotta admit, it's an excellent excuse to buy a TIG welder...
I also want to build up the outsides of the runners on the single plane OFFY and Dual plane Eddy (thanks to @rumblefish360) dual quads to be able to gasket match to the runners on some 308, Trick Flow or Eddy heads.

www.weldingtipsandtricks.com%2Fimages%2Fxtig-welding-aluminum-tee-2f.jpg.pagespeed.ic.SmstKIz_Jj.jpg
 
If you can Tig in a block, that’s awesome.
Otherwise, I would just use a thin piece of metal cut oversized to cover the heat cross over.
The am not to comfy & cozy with a lot of JB weld in a spot that could be troublesome. Perhaps, maybe an epoxy, maybe. It’s just such a large area. I’m not fully aware of the ability of anything to cover that much area and have confidence over the long haul.
 
rumblefish360 said:
If you can Tig in a block, that’s awesome.
Otherwise, I would just use a thin piece of metal cut oversized to cover the heat cross over.
The am not to comfy & cozy with a lot of JB weld in a spot that could be troublesome. Perhaps, maybe an epoxy, maybe. It’s just such a large area. I’m not fully aware of the ability of anything to cover that much area and have confidence over the long haul.
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Yeah, I was thinking on just TIG'ing in a block of aluminum in those ports.

For the cheap and easy route, I was thinking I could cut some 1/2" or 1/4" G10 to size, epoxy it in place about a 1/4" deep and fill that 1/4" pocket with the JB Weld.
 
I have not done this myself, but I have always been told, a thin gauge metal to cover the cross over port works well. It has to be thin to not cause a problem with the gasket and sealing, even though that is the least problematic spot.

I was instructed to place the block off plate on the head and the gasket over it.
 
You guys are overthinking this...cut 2 pieces of sheet metal slightly over size of the port...slap some sealer down and install them...install intake and GO

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rumblefish360 said:
I have not done this myself, but I have always been told, a thin gauge metal to cover the cross over port works well. It has to be thin to not cause a problem with the gasket and sealing, even though that is the least problematic spot.

I was instructed to place the block off plate on the head and the gasket over it.
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Did anyone ever specify thickness? 1/16" 1/32"? I suspect that 1/16" may be a little thick unless you were to cut the gasket to the shape of the block off plate.
Or maybe I'm just over-thinking this.

How am I gonna justify a new (or used) TIG welder though?
 
Sorry no. But I like the 1/32 idea.
Anybody been there & done that?
 
rumblefish360 said:
Sorry no. But I like the 1/32 idea.
Anybody been there & done that?
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I don't know the thickness, but, I use to use metal from old oil cans to do this, but since oil doesn't come in metal cans anymore, I have a few of the wife's old baking sheets that I cut pieces from for various projects, including this one.
 
On one of my trucks I cut pieces of thin stainless which happened to be almost as thick as the gaskets, then traced around them on each gasket, cut with exacto knife and then installed sealing everything as normal. IMO better than laying on top or underneath the gaskets.
 
I was thinking SS for material but it isn’t exactly always a common item laying around.
 
if your using a heat riser they will burn out / last a little longer with headers
 
rumblefish360 said:
I was thinking SS for material but it isn’t exactly always a common item laying around.
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Just hit up home depot. The 16 ga was thicker than tue gasket, the 22 ga is on the thinner side, but a little formagasket should do the trick.

Felpro 1243 gasket
22 ga made in USA steel sheet

15867189013883721377690030540027.jpg
 
65Val said:
Ummm...the main idea is to not make the heat rise?????....You must wire the heat riser open, or remove the flapper all together.
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It’s more of blocking the passage in the head than the heat riser which is no longer (or should be) part of the game plan.
 
65Val said:
Ummm...the main idea is to not make the heat rise?????....You must wire the heat riser open, or remove the flapper all together.
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If you block the ports you have to wire it open, or remove it! Headers are an even better idea.
Use thin 26-21 gauge stainless steel, monel, titanium (anything that can take the heat) sandwiched between the gasket and the head.
 
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