Kitfox Aluminum Radiator retrofit to early S7

[Dave S]

Jch,

Sorry; but, I missed your query earlier concerning what comes with the radiator. Try to make amends now

When I ordered the radiator, Two things came in the package - the radiator and the AN plug for the radiator drain. I think the threads on the radiator drain are the same for the old and new radiator. Only difference was the plug that came with the old radiator was a hex head/brass while the new one was an internal hex/aluminum.

[Jch]

Thanks for your reply. They didn't send me a new radiator plug and I assumed that it was ok to use the old one but now I am wondering if the old radiator was copper or brass should I not put that old plug in a new aluminum radiator?

[Dave S]

Jch,

I don't think the radiator comes with a plug - it's a separate line item to order.

I am certain there are differing opinions on this; however, If a person looks at engineering data and potential for galvanic corrosion, brass and aluminum are of moderate concern so there is some potential for corrosion to develope. My old radiator was brass and had a brass plug, The new radiator was aluminum and and an aluminum plug was used. I am inclined to believe the engineers and use the same material for the plug that the radiator is made of.

I think there are a couple types - The aluminum plug I got came from Kitfox had an internal hex for tightening with an allen wrench. I think aluminum square head plugs are available with drilled holes from places like Aircraft Spruce; and Kitfox may have them too although with the tapered threads of a pipe plug, I don't think a person needs to be concerned about a plug backing out on its own.

At any rate, corrosion does not happen overnight and using a different plug for a short time till a person can get a compatible one shouldn't be an issue.

[jrevens]

Jch,
Dave is right... best to use an aluminum plug. When dissimilar metals and moisture are combined it can be a recipe for galvanic corrosion. Using a good thread sealant can mitigate the potential problem by keeping moisture from entering the threads, where the metals are in intimate contact. Consider this also... I think builders switching from the old plastic fuel header tanks to the aluminum ones often transfer the original brass fittings. It's probably not a huge issue because again, the threads should be well sealed and they're not constantly exposed to water. I used all aluminum fittings on the header tank. You can get an aluminum plug from Kitfox, I'm sure, or from any of the aircraft part suppliers, automotive "speed" shops, etc.