Cracked bearing caps and stripped threads.

baldy110 wrote: 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.

For what it's worth...the 650/750/4 engines have 8 small (2 bolt) caps, not caps that are ganged together like the larger engines. Removing the bridge will replicate the same configuration as the smaller engines which should be fine.

A lot of times the cams aren't in the right place and the locator in the cap and on the cam will bind, stripping the threads or what's worse, cracking the cap or both.
Steve

As a follow up to the stripped threads issue, this post was made in another thread (from a week or so ago) on this subject...

Using vice grips like shown to seat the cam down into the bearing saddles will greatly reduce stress on the threads. I like to use TWO sets of vice grips per cam but you get the idea (the attached photo is from the Suzuki GS850 manual). Using the caps and threads to seat the cams against the valve springs puts a lot of stress on the threads and should be avoided.

It has been mentioned in other threads concerning stripped threads but not this one yet. I would recommend using Time Certs for the stripped threads at this point. Especially since the heli coils did not work. They are more expensive to get the kit but the hole you have to drill is bigger and may work better with the stripped hole now that it is enlarged already.

Thanks for the info guys, I'll check out the time certs for the two stripped bolts, and just remove the bridge. I didn't think the bridge was much of a structural part. My manual specifies 12 ft/lbs for the cam bearing cap bolts, which is what I set my wrench to, they may have already been overtightened at one point weakening the threading. I do have to take the entire head off at some point, the rubber timing chain gasket seeps a bit at the front of the motor, I may just do all this at once.

Once again, ya'll are a vast knowledge and I appreciate the help!

That's 144 in lbs. way too high should be 60-80 (or somewhere near that) also if you used a ft lbs torque wrench that's at the bottom on the torque range, it will be WAY off and probably over, hence the stripped threads.

If it's the one with the locator, you need it as one piece. You don't want that cam wandering side to side.
Steve