Dielectric grease on spark plug boots?

[jimbo]

I have my auto plug harness all made up now wonderingly if any lubricant or dielectric grease or both should go into the spark plug boot. Where is it applied, what is applied, and what purpose does it serve? Don't want it to slip off too easily (in flight).

Jim
RV9a

[BillL]

Originally Posted by jimbo

I have my auto plug harness all made up now wonderingly if any lubricant or dielectric grease or both should go into the spark plug boot. Where is it applied, what is applied, and what purpose does it serve? Don't want it to slip off too easily (in flight).

Jim
RV9a

In automotive, there are a couple of reasons for the dielectric. 1. Corrosion sealing from possible salt or oil flooding in the case of my BMW :-(, and 2. for the push rod V-8's with plugs near exhaust manifolds it acts like a heat transfer medium to keep the boot cooler. Yes, the plug actually cools the boot. The silicone boots will evaporate pretty quickly if dielectric is not used with a SB Chevy and headers.

So. if it is near exhaust pipes (lower) then it seems appropriate for application. Just dab the size of a q-tip head. Ford, Chevy etc have a specific dielectric for this, but it may be available at the typical auto superstore. My tube has lasted decades, so no current source, sorry.

My stupid, unreliable Saturn did not have dielectric on the coil ends and they got corroded. The ECM interpreted the delay of discharge (due to added distance) as due to a bad coil and they wanted $500 to fix. Buffed the ends, lubed, reinstalled and never again. I bet they saved $0.000001 per car.