Packard Forum Index » Post-War (1946-54)

Fred - About a reflective surface on the fuel pump heat shield, how about some kind of insulation material on the outside surface? Maybe some of the insulation material that is used to wrap exhaust headers and pipes would be a good candidate. There are a couple of ways this could be fastened to the shield with a high temperature adhesive or with small screws.

Also, is your fuel pump installed with all the insulators? There should be a thick insulating gasket between the pump and engine; there should be insulating sleeves in the pump bolt holes; and finally there should be insulating washers under the bolts. Often these insulators are left off and many folks do not know about them.

Hope this helps.

(o{}o)

Years ago, in the mid-1970s I was looking at the new Datsun B-210. I remember seeing a small electric fan in the area of the carburetor to provide cooling and I guess to lessen vapor lock. It looked like an after thought and do not know how well it worked. Still an interesting idea. I did not buy the Datsun.

(o{}o)

The heat shield as I understand it is a sheet metal part that does not touch the fuel pump or the exhaust manifold. Therefore the heat shield is supposed to block radiation heat transfer between the hot exhaust and the fuel pump. Radiation is heat flowing across a gap, similar to the heat you feel from the sun. Radiation heat transfer depends greatly on the temperature difference between the hot and cold objects and to a smaller extent on the emissivity of the two object surfaces. Emmissivity is a property of a surface that depends on things like color and gloss. The highest radiation heat transfer is to or from a dull black object. The lowest radiation heat transfer is to or from a shiny surface like chrome. I am sure the temperature of the heat shield would be lowered if its upper surface (or the manifold) were polished and chromed. If the heat shield is cooler the radiation to the fuel pump would be reduced somewhat.

A sheet insulator on the bottom side of the shield would lower the shield bottom surface temperature a bit. However I think a shiny top surface would have a greater effect. Some thermal analysis or testing is in order to get numbers.

The biggest effect by far is having a heat shield on the car instead of not having one. Perhaps that is why Packard did not bother with polishing the heat shield.

Also on my fuel pump there is no insulator at all between the engine and the pump except a thin gasket. There are no bolt insulators. Does anyone sell those missing parts? I am sure I could make them if I had the required insulator thickness. Putting an insulator between the pump and the block would also change the action of the fuel pump. Does anyone know what this does, good or bad?

McMaster has some thin flexible insulation in various composition and temp ranges. 6" wide strips -- both reflective or just ordinary coloring. Some are available in 1' long pieces and not too expensive. Might be interesting to see just what difference if any it would make. The reflective might duplicate what would happen with light color or chrome plating.

The gasket between pump and block is the same for all -- roughly 1/16" thick fiber type -- so no worries about changing mechanical operation. The insulators mentioned are phenolic tubes that surround the bolt and fit in oversize holes in pump body. Prevents direct metal to metal heat transfer. Yours are probably there - or if not, someone found some way to make something else fit in the pump body - otherwise the pump would have a lot of slop. There are also phenolic flat washers under the bolt heads to complete the job.

I got it, get the insulated fuel line coverings, and attach them with wooden clothes pins. Also, attach the heat shield and fuel pump with insulation washers made of wood. I wonder if coating all the wooden parts in high gloss urethane finish 'wood' help?

Interesting Howard . . . I hadn't realized the spacers were to reduce heat transfer. I should have done, it's kinda obvious now! I had wrongly thought they were mainly to reduce noise plus pad out the holes to appropriate size. Thanks for that info.