Camshaft bearing cap stud

[Vanden Perre]

I realised today that one of the nuts holding a cam shaft bearing was not properly tighten. I thought it was a minor detail and that my best 1/2" spanner would solve this in seconds. Unfortunately it appears that the thread in the head is gone.
Does one of you have experience with drilling and tapping the head to a bigger diameter and fabricate a special stud in order to solve this problem? If yes any advice?
Thanks.

Olivier.

[types26/36]

I. I thought it was a minor detail and that my best 1/2" spanner would solve this in seconds. Unfortunately it appears that the thread in the head is gone. Olivier.

Oliver, are you sure it is the stud threads(in the head) that are stripped and NOT the nut/nut threads on the stud that are the problem?
I had a problem a few years ago with a stripped camshaft stud but it was rectified by an engineering company, I think by fitting a new stud without the rounded un-threaded portion that is on a standard Lotus stud. Good luck.

[john.p.clegg]

Olivier

Not done one myself but it could be a half hour repair job if you helicoil it,UNC springs to mind

John

[Vanden Perre]

Brian, yes I am sure this is the thread in the head. No doubt, the stud is on my workbench and inside the thread is material looking like aluminium from the head!
John, ever heard of Loctite Form-a-thread? Seems interesting but the problem is probably to clean properly the hole from the oil as this kind of product is most likely not working well on oily surfaces. See attachment.
Thanks for your help.
Olivier.

[robertverhey]

Yep, happened to me: steel stud + alloy head + overtightening = stripped thread in head. Helicoil is the solution, might even be possible with cams in situ, if precautions are taken to avoid shavings going anywhere

Robert

[alexblack13]

Dont panic! this is a very simple repair. Have it helicoiled or recoiled. Buy a kit of the size required. It gives the required drill size. You must use this. Done with care this can be done hand held, although I tend to use my Mill for this. Drill the hole to depth and NO MORE. most helicoil / recoil inserts are 1.5 times the dia, but longer ones are available special order. Screw in the helicoil insert. Use the tool supplied to snap off the 'tang' on the insert. Make sure insert is just below the surface of the head. Screw in NEW (pref') stud. Job done. Helicoil / recoil inserts will accept 1.25 x the normal torque. So the job is stronger!

Alex B....