Engine: Intake manifold

[Mridgway]

This has been discussed in the recent past,but here we go again. I have read on this forum that blocking off the center exhaust ports to reduce carburetor heating can be a good thing to do. I have the intake manifold off and may as well do the blocking off while I'm at it. I have some forty thousandths stainless shim stock I can use.I will be using steel gaskets.Will the shim stock blocks seal,since they are not ridged? I can cut the center sections of the gaskets out,but will they seal? Is the change a good one? I run an electric fuel pump and a six bladed fan,but I still have idleing problems in the summer when idleing for very long. All suggestions appreciated.
Thanks,Marshall

[Mike Van Veghten]

Way too thick. Do not use .04" material.
In a warmer climate, yes, blocking off the center port is fine, I do it all the time, but I live in SoCal.

You say that you are having idling problems, but you don't give any specifics..! The center port heat does not create an idle problem, it would normally be of help to vaporize the fuel, which is a good thing.

When was the last time your valves were adjusted ?
How long has it been since the carburetor cleaned and properly adjusted ?
Is the ignition timing set to help this. A few more degrees than what the "book" says is a good thing.
What is the pressure that the electric fuel pump putting to the carburetor ? Over about 4psi is too much.

Tell us more DETAIL.

Mike

[StudeRich]

Is your Heat Riser Valve on the Right Exhaust Manifold working properly, or stuck CLOSED?

We ARE talking about a Studebaker V8 Engine right?

[bensherb]

I blocked off the exhaust crossover ports in my manifold with 20ga sheet. I cut a small recess in the manifold for it to fit into so it would not interfere with the gasket or sealing.

[DieselJim]

Fairborn Studebaker sells the gasket set with a block off plate.

[DEEPNHOCK]

First thing.
To do this you need to either wire open, remove the shutter blade or gut the heat riser valve on the RHS exhaust manifold.
Use a composite intake manifold gasket that has the heat crossover opening eliminated.
I have very thin stainless steel sheet stock cut to just cover the opening in the head.
The metal is to protect the gasket from the extreme heat pulses from the exhaust.
The sheet is thin enough that it will deform the composite gasket without causing gasket sealing issues.

Usea high temperature RTV sealant (Permatex Ultra Copper is my choice) and put a small film around the heat crossover port on the head (not a bead..... just a fingertip film)... Put the blockoff plate in place and move around a bit to seat it on the head.
Go away and don't come back for a while. Let the RTV set up.
Next. Flip your bare intake manifold over (squeaky clean, right?)...
Apply a thin film (not a bead) of that Permatex Ultra Copper RTV on to gasket surfaces.
Apply the composite gasket and move it around to seat it nice and flat, and nice and aligned to the bolt holes at each end.
Go to bed and don't come back until the next morning.
Then... Apply some white lithium grease (or similar thick lube) tothe clean gasket surface.
Install the intake manifold onto the engine. The grease will allow you to position the intake without damaging the gasket.
Install your bolts and tighten properly using the service manual procedure and torque value. This is important,
Continue with your other items.
This method has worked for hundreds of Stude enthusiasts.
The lubed gasket trick is nothing new. An old racer's trick to save the intake gasket for multiple re-use.

[PackardV8]

Use a composite intake manifold gasket that has the heat crossover opening eliminated.

Where are we getting composite intake manifold gaskets these days? The FelPro sets we've been using all have the steel shim gaskets.

jack vines

[Mridgway]

I didn't give enough details in my post,so I'll start again. This is a 1960,289 that was in a parts car(HAWK).I rebuilt it in 2009.That included boring 20 over and crank grinding( I don't remember that dimension.Head work hardened valve seats.A new heat riser valve with 2 1/4 inch exhaust and an H pipe. Edlebrock 1406 carb with electric choke.The cam reground to R1 specs.The engine has about 6k miles since rebuild.I have not readjusted the valves for about 3k miles. I do run the timing a little advanced(haven't checked it lately).I adjusted the carb. for the best idle.Distributor is stock.It seems that it idles much better in cool weather than in hot weather. Since the manifold is off,I don't want to wish I had blocked the heat passages later.All replies are appreciated.
Thanks,Marshall

[jif988]

manifold

I didn't give enough details in my post,so I'll start again. This is a 1960,289 that was in a parts car(HAWK).I rebuilt it in 2009.That included boring 20 over and crank grinding( I don't remember that dimension.Head work hardened valve seats.A new heat riser valve with 2 1/4 inch exhaust and an H pipe. Edlebrock 1406 carb with electric choke.The cam reground to R1 specs.The engine has about 6k miles since rebuild.I have not readjusted the valves for about 3k miles. I do run the timing a little advanced(haven't checked it lately).I adjusted the carb. for the best idle.Distributor is stock.It seems that it idles much better in cool weather than in hot weather. Since the manifold is off,I don't want to wish I had blocked the heat passages later.All replies are appreciated.
Thanks,Marshall

Hi Marshall, some years ago I blocked off the manifold heat passages with furnace cement. I kept pushing it in until I had the passages filled up, then smoothed out the ends with a putty knife. I got the gaskets from Myers Studebaker, they are composite and run about $13 for the pair. I also eliminated the heat riser valve and replaced it with a spacer, also from Myers. The result was that the car (64 Avanti) runs and idles great even on hot days, prior to this I had trouble with hot idle, the car wouldn't idle because the fuel in the carb was boiling over and the mixture was too rich. Hope this helps...

[DEEPNHOCK]

Phil Harris at Fairborn Studebaker, Myers Studebaker, and Dave Thibeault both have the composite (Best) intake gaskets.

[rkapteyn]

http://www.studebaker-info.org/Tech/fuelvaporization/sdc44467.html