Opinion needed: Stripped threads in aluminum housing

motomoron wrote: Send me the cover and I'll Helicoil it for you.

I strongly feel that a helicoil or any kind of thread insert is not the answer here. The casting is thin. Threaded inserts work well where they can be self-retained. Helicoils are almost a 1/2" tall. He has a very thin casting.

What I'm suggesting permanently replaces the hole in the casting with something beefier. Like this:

After affixing an NPT plug of some sort, he has multiple options for sealing the hole; straight bolt with an O-ring, NPT plug, or skip the plug and do this:

OR this:

That way, if the hole needs to be opened for draining, its not affecting the threads in the thin casting. If the draincock fails, it can be easily replaced with another one, but the opening/closing of the hole is no longer a wear item on the thin aluminum casting.

JMO

I did this exact trick (except I did use 1/4 turn ball valves) in the SBC in my boat. Instead of fighting with NPT plugs in the block every year to winterize, I just put some 1/4" NPT ball valves in the block drains. Winterizing now takes me 3 minutes and I never have to fight with corroded plugs in cast iron anymore.

I used to winterize dozens of boats each year and I wish they all had quarter turn valves.

For the trials bike, I don't really want anything sticking out that will get smashed by a rock. Don't want any extra leverage.

I think the solution, in this case, is going to be the o-ring plug.