Cracked bearing caps and stripped threads.

Found this the other day when replacing the cam end caps. It appears it cracked because two of the bolts had stripped their holes. That being said, i tried to helicoil the holes, and it just stripped again when I tightened the bolts back down. I guess that means it's time to find a new head. Is there anywhere that specializes in aftermarket performance products for the 1100 that doesn't cost an arm and leg? I'd like to rebuild the motor with bigger valves, performance cams, and new head.

Thanks!

If the actual shell that holds the bearing isn't cracked it shouldn't be an issue, but stripping out helicoils means either it wasn't done right, or you cranked the bolt way to tight or something.

Doesn't cost an arm and a leg? To so what you are asking, will probably be a couple grand, and to me, that's an arm and a leg. I'd get the bolt holes fixed, if possible after the second whoops, and enjoy riding

You can have that crack welded.
Steve

Am uncertain about the particular model at hand, but the FSM likely specifies INCH pounds for torque of cam cap screws. Perhaps only 95 inch pounds or less, which is reasonably "snug" -- and not very tight at all.

It's also important to assure that the blind holes in the head are clean and clear of any oil or other foreign matter before starting each bolt into its respective hole. Can use compressed air to blow out the empty holes.

The Helicoil should have tolerated as much or more torque than would the stock threads.

Good Fortune!

Absolutely. Now that the damage is done, I'd take two of them, bolt them together with the locator pins in them and have the crack welded. If the threads are too damaged, I'd take the head in, have them weld, drill and tap new threads.
A handy thing to have on hand is a baby snot sucker. Cheap and you can get them anywhere. Good for a lot of things. :whistle:
Steve

I generally don't torque bolts that small (torque wrenches are unteliable at the lower and upper end of their scales) i just snug them up with a short wrench and call it a day, more criitical bolts get a bit of thread locker to go with.

If you use vice grips to clamp the cams down into the head before installing the caps the stress on the threads is greatly reduced.

I don't think the broken caps will cause an issue as long as the bearing shell is held tight. And I wouldn't weld them because that will cause distortion.

If possible I'd try to find some timeserts and stick them in the head to fix the threads. They are stronger than helicoils. Then use the vice grips to avoid thread stress.

floivanus wrote: I generally don't torque bolts that small (torque wrenches are unteliable at the lower and upper end of their scales) i just snug them up with a short wrench and call it a day, more criitical bolts get a bit of thread locker to go with.

This is why it is so important to use the correct torque wrench for the job (assuming you're going to use a torque wrench). Using a large scale torque wrench for cam caps will usually lead to stripped threads; a small torque wrench calibrated in inch pounds is the one to use for that job.

As far as doing the job without using a torque wrench, that's fine if that works for you since clearly you have the discipline and feel for when to stop tightening the fastener. The problem occurs when folks feel compelled to turn that fastener just a little tighter - then ooops. That's when they move from snug to stripped threads. Ed

Agreed on that last little turn bit.

Truth is I have a five or six year old snap-on 1/4" drive torque wrench, and I have felt the inconsistency with it enough times on the low end of the scale to where I don't trust it on the lower end of its torque range. But in critical things it gets used frequently.
I have also seen several times, when I wrenched in a shop, someone confuse in lbs and ft lbs and snap bolts or pull threads.

For a new wrench it is important to have the correct tools including a factory service manual. This is one example why.
Steve

Send a pm to kz10006(brian) or larry cav and see if one of them has a junk head with good caps you could try to replace the broken one on your head.

That crack is not going to be a problem. It's called a bridge crack and that bridge does nothing really. As long as the crack is not into the cap itself your fine. Take both caps off and cut the bridge off the remaining cap. No need to weld anything. As far as your helicoil problem it sounds like it was not installed properly. I have installed dozens of helicoils in cam caps holes and never had one that failed. You can try timeserts but if the head is already buggered I would take it to someone who really knows what they are doing. That is not going to be an easy garage fix.