Heli-coil time?

I was just out getting ready to check the valve clearances on my KZ1000B4 and was checking the torque on the cam cap bolts when one of them kept spinning. I pulled the bolt and the threads are OK (that figures) so, are heli-coils the way to go to fix that problem?

Please tell me I don't have to pull the head!:ohmy:

Sonny

i would guess yes as far as heli-coil cause iirc
those bolts are a low torque value....my initial guess is you dont have to pull head, but be real carefull where the small bits end up....im sure the more knowledgeable will step up....good luck...keith

Every one of my cam cap bolts are heli-coiled. spread some grease around to pick up the shavings and clean every thing real good and you should be good.
Mark

the big question is can you get at it comfortable enough to drill it perfectly straight if you can't then if you dont want to pull the head then look at taking the motor out the frame to do it because it has to be drilled straight and the motors arn't hard to pull. also like mark said plenty of grease on the drill bit and take it slow.

timebomb33 wrote:

the big question is can you get at it comfortable enough to drill it perfectly straight

Luckily, it's the most outside bolt on the #1 and #2 exhaust cam cap so, it's pretty easy to get at.

I'll check the local Advance and Autozone stores tomorrow to see if they have the kits available.

Thanks all,
Sonny

I've always prefered to use solid inserts instead of the coil type. There are several kinds--Time-Sert, Keysert, etc. They're easier to install--some require no special tools other than a drill bit, tap, and flathead screwdriver. Also, they are more durable than helicoils--once installed, they won't come out or disintegrate like coils do.

I bought my inserts at a local Ace Hardware in the section where they've got rows and rows of drawers selling all kinds of bolts and misc. fasteners. If you've got a place like that near you, chances are, one of those drawers will have metric thread inserts (the solid kind).

From my experience, if the stripped cam cap bolt is one of the outside bolts, you should be able to repair it with the head still mounted on the engine. If it is one of the inner bolts, and the engine is still mounted in the frame, it may not be possible to get a drill bit and tap in there without hitting the frame.

Another tip for keeping the drill shavings out of your engine: Cover the head with aluminum foil. Use your finger to push down the foil over the hole to be repaird so that it form-fits over the hole. Next, as Mark suggested, smear a small glob of grease around the foil over the hole. Now when you dril, the shavings will be caught in the grease, and the foil covering the head will help ensure that no stray shavings fly into the engine unnoticed.

You won't have any problem. The existing bolt hole guides the drill bit straight without much effort. The exhausts will always be the ones that strip, rarely the intake caps. Don't go by some manuals torque specs which can be as rediculous as 14 ft/lbs. Guys here have recommended 8 ft/lb or 96inch/lb. I recommend tightening the same as the 6mm valve cover bolts which is 5.5ft/lb or 66inch/lb. They are not going to ever come loose because they have constant pressure from the camshafts pressing on them.

Unfortunately, Ron is on the money... the recommended torque spec is too high for an M6 bolt. His recommendation to tighten at 66 in/lb is about right I suspect. I use RECOIL inserts because my carb hardware supplier carries them as well as TIMESERTS. TIMESERTs are probably better inserts but are far more expensive. The RECOIL inserts work fine and are similar to helicoil. You can do ALL the cam cap hole thread with the cylinder head in place. It is probably a good idea to remove both cams, tie up the chain and sop up all the oil you can. Put some rags down and make sure you get all the shavings. I don't bother grease the drill as some shavings will get away. If the head is dry on top, it is easier to clean up than if the shavings float in oil. I have had heads that NEVER stripped and some that all strip. I suspect that the difference is the amount of times the cam cap bolts have been tighten to factory torque spec in the past.

wiredgeorge wrote:

Unfortunately, Ron is on the money... the recommended torque spec is too high for an M6 bolt.

I was wondering about that when I started and looked in my manual and it recommended 12 ftlbs. I was using a inlb wrench and screwed it up to 144 inlbs, thought about it, and backed it down to about 90 for the first try. It still stripped...

Sonny