phenolic vs wood carb spacer

OK, time for the degreed chemist and 27 year aerospace engineer to chime in.

Moparmarcus, it is best not to use a polyurethane coating in fuel applications unless it is rated for it. Not all polyurethanes are equal and they can swell and begin to break down when exposed to fuel.

Everybody, phenolics are a type of plastic that have widespread use for fuel applications because they are inert to gasoline and they are also thermo-insulating. They don't transfer heat and they are stable at high temperatures. In fact, one particular type of phenolic plastic is used as a re-entry heat shield on space capsules.

A phenolic impregnated wood spacer has the excellent insulating property of wood while having the fuel resistance property of a phenolic at a lower cost than an all phenolic spacer. Either one is better than an aluminum spacer when one wants to keep the fuel mixture at a lower temperature before it reaches the intake.

Art