911 oil galley plugs

[mikensam]

Just picked up tool room lathe,Think its an 13x28in(Still in the U haul behind my house,havent sorted it yet)and need to turn some oil galley plugs.Indexed the old plugs numerically/photos.Like to know what grade aluminum bar stock to use and does it matter?(Thermal expansion,ductility,other variables I havent even guessed at)Any input what be greatly appreciated,and would be happy to make sets for anybody while Im in there.Its a 2.2L 1970 mag case.

[HawgRyder]

6061T6 is easy to work with.
Don't forget to put a very slight taper on the OD so that it wedges in correctly.
Bob

[mikensam]

Thanks for the input Bob,was thinking of .002 taper end to end,then dry icing the plugs before install.Frigging magnesium and high pressures pucker me.Took a slide hammer and finesse to get em out.Want to get her right the first time,don't want to stress the mag.Was thinking of pipe tapping the galleys,but this motor will be lucky to see 180hp,and the risk seems to out weigh the benefits.( tapered pipe threads scare me)
Heading out to Aircraft Spruce for bar stock and rod ends tomorrow,any advice on taper dimensions or installation techniques,or other viable options would be greatly appreciated.

Chris

[HawgRyder]

Chris...if you freeze the plugs and press them in....be careful not to make the plugs too big....or when they normalize (temperature)
they might split the case.
I think a .001 - .015 interferance fit might be about right...but just in case..find out what the expansion factor of both aluminum and magnesium is.
When I do plugs...I thread them in...using pipe style taper taps and thread count for the plugs.
It makes it a lot easier the second rebuild around...LOL.
Also...it makes sizing a lot easier.
Bob

[KTL]

Originally Posted by HawgRyder

When I do plugs...I thread them in...using pipe style taper taps and thread count for the plugs.
It makes it a lot easier the second rebuild around...LOL.
Also...it makes sizing a lot easier.
Bob

Same story on the cam tower plugs for the oil spraybars. Pulling out the tiny aluminum plugs is a pain in the butt with the need to drill, tap and extract such a small plug.

I installed 1/8 in. NPT inhex plugs in my cam towers for that very reason. Next engine refresh that involves cleaning of the spraybars will be easier with the threaded plugs

[mikensam]

Thinking of going the treaded plug route.Does 5/16,1/2,3/4 and 7/8" cover the four NPT plug sizes?

Thanks,Chris

[swade]

NPT

National Standard Taper Pipe Threads Size NPT Chart - Engineers Edge

W

[mikensam]

thanks swade