Cam Stud - Broken and bodged - How to repair?

[AHM]

Hi All,

At some time in the past one of the short cam studs has been broken, drilled out badly at an angle and too deep, then tapped, and the spacer filed at an angle to accomodate the lean of the stud.

The head is on the bench.

Suggested methods of repair please?

thanks,

Simon

[rgh0]

weld it up and redrill and tap properly if you can find a welder capable of doing it well and not putting to much heat in the head

You say the "spacer" has been filed at an angle - I presume you mean the cam bearing cap or do you mean the hollow dowel that aligns the bearing cap to the head. I am not sure how the cam bearing alignment has been maintained if this has been done.

cheers
Rohan

[robertverhey]

Another possible option... if you could drill staight down (using a drill press with the head properly mounted perfectly level underneath), there might be potential to drill out and helicoil?

[k44ent]

I think the OP means the hollow dowel has been shaped to maintain an upright location for the bearing cap to locate on but that must mean the bearing cap has also had the hole altered so not sure how this would work. Agree that the best solution is to weld up and re-drill. Needs to be done by a specialist but am sure someone on here will know one. I heard that no twincam head is beyond repair so am sure things will be ok.

[AHM]

Below are a couple of pictures.

Sorry yes the dowel!

It all assembles ok but the nut will be at a slight angle.

[rgh0]

The cam bearing caps dont take much load - especially the rear one. The prototype heads did not even have the 5th bearing cap and it was added later during development. If the cap assembles ok and the bearing alignment is correct and it is just the nut is at a slight angle then an option is to just leave it as it is if you dont want to go to the hassle and cost of getting it reinstalled correctly.

Long term though it really should be fixed properly

cheers
Rohan

[kstrutt11]

I once used thread inserts in a similar situation on a rover v8, I can't remember the brand name but they work a treat, you drill it oversize tap it out then screw the insert in and drive some stakes around the side in to lock it in.

[holywood3645]

Drill and retap next size up and have a custom stud made to suit.
James

[AHM]

More thoughts...

The hole has gone off to one side so helicoiling would be tricky.

I don't think that it would be straightforward to weld up the hole without making a big job of it. But how about filling with JB weld and then tapping to the original size or helicoiling.

I was reading another thread that mentioned JB weld ? Never used it myself is it any good? Are there other Aluminium alternatives?