Carb heat shield

[Normspeed]

Been working on a heat shield to go under my carbs. Part of my ongoing battle with fuel percolation in hot weather. I measured the carb spacing and available room on the motor and mocked it up with a couple old carbs. Yesterday I drilled and cut the aluminum shield. Came out pretty good for just hand tools.

When I trial fit it I'll need to trim for linkage clearance, and I might separate it into two separate shields. I'll also be removing the two bakelite spacers I installed. A friend of mine has one of those remote thermometers and we found that at operating temp, the spacers are considerably hotter (15 degrees or more) than the aluminum manifold and the carb bases.

[Powerhouse]

NEAT...I am thinking of doing the same. Last weekend a friend of mine worked on another friend of mines car by adding a heat shield like that to his carb on 47 Pontiac. He used an asbestos impregnated board instead of sheet metal. It solved the problem of vapor lock right away. He also rerouted and changed the fuel line to be as far as possible from the hot stuff. He was thrilled! The car is actually the movie car used in some movie...here's a link..http://imcdb.org/vehicle_24986-Pontiac-Streamliner-1947.html

[randroid]

Norm,

Other than requiring an extra pair of gaskets it seems like an excellent idea, and if you can cut metal that nicely a gasket shouldn't slow you down. I'm anxious to hear your results.

-Randy

[T120]

I took this photo last weekend.Heat shields on a Hudson dual carb.They were

stainless...Interesting shape - dished slightly upwards on block side,I guess to help direct heat/air flow

[dezeldoc]

You could also make some isiolators out of hardwood about 1/4-1/2" thick and use longer studs, that will cut down on the heat transfer between the manifold and carb.

[Normspeed]

Mine will be creased upwards towards the cylinder head too. I want to avoid too much heat buildup under the shield at the head.

I saw a real similar set of shields on another Hudson recently. Maybe an aftermarket part for those big sixes back in the day?

Today I notched the plate to match up with the small hole in the carb bases. The gaskets have 4 notches (idiot proof) but you only need one, at the right front of each carb. I'm using a bunch of gaskets that I kept from old kits. Under the shield I'll go with the 1/8" thick cardboard gaskets, and above it, the standard thin ones.

Dezeldoc, I agree wood or aluminum might both be better material for spacers. The ones I have were made for older Chevy sixes and are a hard dark brown material like bakelite. I noticed after I installed them, a little less snap when I got on it in low or second, so I'm hoping I'll get that extra ounce of power back when I take them out. It means going back to the shorter studs and re-adjusting the linkage and return spring setup though.

[Normspeed]

For anyone following this, I've been tweaking the fit on the heat shield. I ended up making one into two, mostly for clearance at the dual carb linkage. I decided to keep the bakelite spacers for now, since they allow the shields to be placed so there's some air circulation between the shields and the intake manifold. I'll also put a slight upward bend in both shields to allow for more air circulation where the manifolds meet the block. Don't want to create a hot spot so close to where the valves are.

Air circulation under the hood seems to be critical on the car, maybe because the 53 has a lower clearance between motor and hood. At the same time I'm doing the shields, I removed the heater box since it blocks circulation, and also removed the fuel pump heat shield which seemed to be blocking a good deal of air flow from the fan back along the side of the motor. I had already removed the metal cover in the fender that comes off for valve adjustments.

Working on the car is a challenge in the 100 degree plus temps we're having. Basically you can work outside until around 10am, then after 5 or 6pm. In between, the heat and sun are brutal.

Edited August 4, 2009 by Normspeed