Aluminized layer reflects over 90 of radiant heat up to 2000f allowing the starter to last longer. The next best is air.
Starter Motor Heat Shield Page 1 Chimaera Pistonheads
How to protect starter from heat. Unfortunately they are often discarded when the starter is replaced. So id try for at least 14 inch spacing between the starter and heat shield. A shield allows for some air flow around the starter but keeps most of the heat from the headers off the starter. The other side of that might be to keep double layer shields closer than 14 inch to use the air between as insulation by keeping it still. The best insulator from heat is a vacuum. The old ford relay add is great until the same old starter acts bad again.
Bolt it either to the engine. I have used a starter that is oe to a 1996 chevy 1500 57350 on three builds to eliminate the old chevy heat soak problem. This will reflect the heat away from starter. Try to fashion something from sheet metal with a bracket that can be used to hold the shield in place. Dont use wrap on your headers. In fact many vehicles are originally equipped from the factory with a heat shield.
Keep yourself hydrated throughout the day by drinking plenty of water or sports drinks that contain electrolytes. Simple easy to install heat shield wrap with an extremely effective radiant heat reflective surface. It will keep your starter cool but usually shortens the life of the headers dramatically. For cooling fins relying on free convection no fan forced cooling a spacing of 14 inch or more is needed. Very thick aluminized insulation helps to eliminate intermittent starter failure due to radiant heat. Also dont forget to wear sunscreen.
My 327 powered 29 model a a 305granny 4 speed transplant in an 81 cj8 jeep scrambler basket case and my 350700r4 85 s10. Heat soak can usually be solved by installing a heat shield on the starter. Dress appropriately to protect yourself from the heat. This includes wearing light colored clothing and safety glasses with uv protection.
Gallery of How To Protect Starter From Heat
