Thorp Air Command - T18.net

Well, see the photo below. There is a second broken stud on the underside of the cylinder too. How can this be fixed?

The stud should thread out once you can get a hold of it. Replacement studs can be a bit of a pain with the minimum torque requirement and getting the proper length remaining out of the case to put the nut on.

I have seen the threads get pulled out but this the first broken cylinder stud. If it was a through stud the case would have to be split.

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Thorp T18
O-320-B3B (160 HP)
68x74 Sterba Propeller

"The joke in aviation is, 'If you want to make a million, you'd better start with £10m.' " -Bruce Dickinson

Thanks Jeff. How would I get out the lower stud out which appears to have broken off flush with the case (rather than flush with the cylinder flange in the photo above).

I'm thinking you are looking at a through bolt and not just a stud. Even if is just a stud, the amount of corrosion on the remaining studs would make me want to tear the engine down for a complete inspection.

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Bob Highley
N711SH
SN 835
KLAL

I hate to say it but I think the jug will have to come off for both. Probably have to drill the bottom one and use an easyout. How hard they come out will depend on what, if anything, was used as a thread locker.

I think the through bolts are on the back side of number 2.

_________________
Thorp T18
O-320-B3B (160 HP)
68x74 Sterba Propeller

"The joke in aviation is, 'If you want to make a million, you'd better start with £10m.' " -Bruce Dickinson

The white stuff on the case and bolts is actually baby powder that I put on the case a couple hundred hours ago in search of an oil leak.

Looks like a no fun job. My concern is what caused them to fracture in the first place ? You may want to contact someone like Divco, there phone # is (918) 836 9101 they have been working with engine cases for 40+ years. They may be able to lead you in the correct direction before you get into something that could have been repaired before messing with it and causing a larger issue.

Phil
118BC

You probably did this , but I'll say it anyway . Soak the nut/stud with something like PB blaster or Kril oil .

RB

I was just looking at the picture zoomed in. It looks to me like there might be some kind of sealant under the cylinder base. If true, that can cause all kinds of nastiness down the road to include broken cylinder studs and possible catastrophic failures. Those mounting flanges need to be clean. Mike Busch did a good article about it...
https://www.savvyaviation.com/wp-conten ... -ya-in.pdf

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Thorp T18
O-320-B3B (160 HP)
68x74 Sterba Propeller

"The joke in aviation is, 'If you want to make a million, you'd better start with £10m.' " -Bruce Dickinson

i would pull the cylinder off . Remove and replace all studs and nuts. Fit new studs with thread sealer to stop corrosion developing . There is enough stud
sticking up to apply the stud removal tool. can buy at any good hardware shop .. J.P..

i would pull the cylinder off . Remove and replace all studs and nuts. Fit new studs with thread sealer to stop corrosion developing . There is enough stud
sticking up to apply the stud removal tool. can buy at any good hardware shop .. J.P..