Fuel Boil/Carb to Manifold Phenolic Spacer

[rheltzel]

Yesterday here in Sacramento, it was 79F. After a long run on the freeway, I parked my '35 in the garage. Five minutes later, I noticed a distinct gasoline smell and checked under the hood...fuel was leaking out around the throttle shaft and I could hear the gasoline percolating in the float bowl. Slightly opening the throttle stopped the leak, but of course gasoline was then just running into the manifold. My infrared thermometer indicated a float bowl temperature of 137F; manifold was 188F.

This morning, I installed one of Bob Drake's phenolic carb-to-manifold spacers designed to insulate the carb from built-up engine heat. Took another long run on the freeway, same outside temp as yesterday, same tank of gas. Parked in the garage...no leaks and no percolation. Float bowl 112F (and actually, I think it was not even that hot...barely warm to the touch. Manifold same 188F.

So, the phenolic spacer seems to work as advertised. Certainly the objective measurements indicate a distinct improvement and with modern fuels not designed for our beloved flattys, every little bit helps, right?

For those of you experiencing hot engine fuel problems (especially for those of us forced to fill our tanks with California's infernal "winter blend" gasoline with its high Reid Pressure rating) I recommend you consider installing a similar spacer between your carb and manifold. It sure worked for me.

Oh, and by the way, kudos to Bob for getting my order to me in just two days with standard shipping.

[ford38v8]

A phenolic spacer can do no harm, and in the case of an early manifold made for the Stromberg, the spacer can be of real value to block off the heat riser third hole.

GM also tried a spacer for the fuel pump without success due to the open chamber direct to the valley. The poorest possible location for a fuel pump, not one of Fords better ideas.

[WestCoast]

you found out what the chevy street rod guys have admitted, aluminum intakes and aluminum carbs are not a good mix, the intake transfers a lot of heat to the carb, thus causing the fuel to boil, emptying the carb fuel bowl and then flooding the engine, a spacer is needed to help control that, at least one an inch thick

[Jack E/NJ]

A nice piece of kiln-dried, heavily-varnished 2x6 works just as well. 8^)

Jack E/NJ

[rheltzel]

Thereby making your car a "woody"?

[Jack E/NJ]

Sponsored Links (Register now to hide all advertisements)

Yes. I wanted to spruce up my woody. 8^)

Jack E/NJ

[Brendan]

I think I was having that trouble yesterday also, Welcome to California!

[scicala]

Originally Posted by Brendan

I think I was having that trouble yesterday also, Welcome to California!

Wanna trade ? You can have Michigan. Then you can worry about carburetor icing.

Sal

[G.M.]

Bob Shewman in my opinion makes the best carb. insulators. His are thicker and drilled for additional cooling. They come with the longer studs. [email protected]
1-610-933-6637 G.M.

[wga]

EDELBROCK 94™ CARBURETOR HEAT INSULATOR SPACER
This is a 1/4" heat insulator spacer kit for Edelbrock 94™ Series and Stromberg 97® 3-bolt carburetors. The black wood laminate fiber spacer is ideal for reducing heat transfer from the intake manifold to the carburetor. Includes all necessary hardware for a complete installation. Part number 8571
http://www.summitracing.com/parts/edl-8751

From Bob Drake - it is 1/2" thick vs. Edelbrock 1/4 inch thick and less cost too.
https://www.bobdrake.com/ItemForm.as...b-1e5aeac19b4c

[39portlander]

Originally Posted by G.M.

Bob Shewman in my opinion makes the best carb. insulators. His are thicker and drilled for additional cooling. They come with the longer studs. [email protected]
1-610-933-6637 G.M.

And his flex fuel hose with the check valve is a great addition as well.
"Get Hosed". Scott

[G.M.]

Originally Posted by 39portlander

And his flex fuel hose with the check valve is a great addition as well.
"Get Hosed". Scott

Scott thanks for the pictures. As we can see the spacer is 1/2" thick and the additional vent holes are visible. G.M.

[G.M.]

Originally Posted by 39portlander

And his flex fuel hose with the check valve is a great addition as well.
"Get Hosed". Scott

I also want to point out from your fuel pump picture the larger clearance between the fuel pump and intake manifold with the cast iron manifold.
With an aluminum intake the pump almost touches the manifold making fuel pump vapor lock more aggressive. This problem is starting up again with the warmer weather according to recent posts. I might also suggest higher fuel pump pressures reduce the VL problem. G.M.

[Steve/IL]

On aluminum intake manifolds, what about a 1" spacer under the fuel pump base to help insolate the fuel pump from manifold heat. Use the longer 8 7/8" fuel pump rod with the 1" spacer! Of course longer base bolts would be required.

Is this reasonable or a waste of time?

[mike42]

I installed the Shewman plate a couple years ago and it works really well. In northern Michigan it does get hot and humid. It really seemed to help !

[G.M.]

Originally Posted by Steve/IL

On aluminum intake manifolds, what about a 1" spacer under the fuel pump base to help insolate the fuel pump from manifold heat. Use the longer 8 1/2" fuel pump rod with the 1" spacer! Of course longer base bolts would be required.

Is this reasonable or a waste of time?

I tried a 1" spacer under the pump but the heat saturation from the aluminum manifold and the dead air space it didn't help. The only thing that helped was a high speed computer fan mounted over the pump but who wants that hanging there? G.M.

[MARVIN, CT]

Last year I installed a phenolic 1/4" spacer from Mac's on my 60hp (single 97). Melted! Mac's refunded my money. Will try something else. Marvin,ct