Topic: stripped long cam tower bolt hole

[fuzzybutt]

like the title says, one of the long bolts that holds the cam tower down has stripped the hole. it's the one down the center that also locates the rocker shaft. whats the best way to fix this? heli-coil or a nutsert ? almost forgot, this is a 76 750k motor in my 74 750k

[Terry in Australia]

It's pretty common Fuzzy, I'd just helicoil it, the head I just took off my F2 has about 6 helicoils in it. Cheers, Terry.

[paulages]

the last engine i put together had no fewer than 6 helicoils in the head from a previous rebuild. the same hole you are talking about was beyond repair, and i had to have a machine shop make an insert for it. it only cost $30 or so-- they basically drilled out the hole much larger, threaded a solid plug into it with threadlock, and then drilled and tap a new hole back to the right size. it's kind of the same concept as a helicoil, except that it is solid metal and you almost can't tell the insert is there.

[Terry in Australia]

Yeah, if you have a drill press you could drill and tap the hole for say, a 10 x 1.25 thread, then just buy a suitable bolt, thread it in with some threadlock, cut it flush, drill and tap it to 6 x 1.

Of course, if the head is still bolted down onto the engine, it's not as easy, so maybe a helicoil would be more suitable. Cheers, Terry.

[MRieck]

 I just Helicoiled those 4 holes on a head for Sean Condon...it's good insurance. Time Sert makes a new kit called a Big Sert (if I remember correctly). It can repair just about hole deemed beyond repair.

[fuzzybutt]

i ended up with a helicoil kit. believe it or not but in all my years of working on cars and bikes, i've never stripped a hole out like this.

[Metalhead]

I hope you did'nt buy a helicoil kit, I think I have one of ever size.
Wayne

[Steve F]

When I stripped out a cam cap bolt, I discovered that the holes the bolts go into aren't tapped all the way down to the bottom.  I just got a metric tap the right size, and some threaded rod and made my own stud cut to length with a ny-lock nut and washer.

[MRieck]

I hope you did'nt buy a helicoil kit, I think I have one of ever size.
Wayne

  Huh?

[MRieck]

 I actually use the Recoil kits (except with the longest Helicoil insert)

[fuzzybutt]

daughters boyfriend had the kit. i had thought about using nutserts but they dont sit perfectly flush and thats necessary in this case.

[Sparked]

Yeah, if you have a drill press you could drill and tap the hole for say, a 10 x 1.25 thread, then just buy a suitable bolt, thread it in with some threadlock, cut it flush, drill and tap it to 6 x 1.

Of course, if the head is still bolted down onto the engine, it's not as easy, so maybe a helicoil would be more suitable. Cheers, Terry.

The only problem you might have with this is if your bolt seizes into the 6x1 thread and you go to remove it and the 10x1.25 comes loose.  I've had it happen once, but then it was in a water pump cast made in china I was repairing. Made for an interesting afternoon and I eventually came up way to solve the problem of the threadlock not holding in the casting.

[bryanj]

Google "Keensert" its the same idea as the 10mm plug but already drilled and tapped 6mm in the middle and has 2 hardened "key" pegs that you tap down to lock it to the head so it cant unscrew.

HINT with all the repairs using plugs use a threadlock on the outer of the plug to stop oil leaking down the thread to the outside world

[fuzzybutt]

when i took the head off again a few days ago i just went ahead and heli-coiled ALL the holes.

[Terry in Australia]

Google "Keensert" its the same idea as the 10mm plug but already drilled and tapped 6mm in the middle and has 2 hardened "key" pegs that you tap down to lock it to the head so it cant unscrew.

Very nice Bryan, I might have to buy some to fix a stripped out an exhaust header mounting bolt hole on my GS1000 head, I managed to bust an easy out (contradiction of terms, IMHO............) in the process, so at the moment it has a special "Terrybuilt" stud, 12mm x 8mm, so to return it to "almost OEM", one of those Keenserts will be just the ticket! Cheers, Terry.

[bryanj]

Terry check the spec on the keensert you want as they dont always use the outer thread pitch you would expect, like i think the 6mm inner is 10x1.5 and sthat is the "oddball" 10mm pitch

[Terry in Australia]

Thanks Bryan, I'll check it out. Cheers, Terry.

[fuzzybutt]

someone gave me a timesert metric kit today, traded him an old peavey amp with a bad speaker for it. the head for the big motor is going to get timeserts in all those 6mm holes when i get to building this winter.