If it was just stripped you could use a helicoil to repair the thread. That's a bit more complicated. You might be able to use a couple of washers for a dodgy repair but there would always be a chance every time the screw was removed that they would drop into the engine.

 

Thank you for your reply.

I haven't had to use a helicoil or similar before, usually opting to just tap larger sized threads, so I'm not sure how they work, but do you think that the depth of the hole without that intact protruding part would be enough for a helicoil or similar to have enough strength to properly torque down the bolt, if I were to use something like washers for a spacer?

Your idea of using washers did make me think that perhaps cutting down to size and then epoxying a bolt collar like below could add enough threads to give it the strength to hold either the bolt or an insert... but I'm not sure. Aluminum terrifies me 😂

 

The cam journal caps are machined with the cylinder head forming a mated pair so caps are not sold separately and you'd have to replace both. However, on the SV rider forum I have heard of people replacing just a damaged journal cap without issue but you might have a problem finding an unmated cap as they are typically sold with the cylinder head and, technically, you should not do this.

I looked up the spec on the valve cover bolt and 14N-m is correct so maybe you misread or mis-set the torque wrench to 14 lb-ft. TBH, I've never used a torque wrench on those bolts because they are not under load or critical in any way other than to stop an oil leak. I just snug them down until my T allen wrench gets a little "springy", if that makes sense. I've never had a leak or bolt work loose. Also, that bolt with shoulder is probably not stripped it just ripped out of the aluminum of the journal cap so the threads can be cleaned up.

You could DIY if you have the tools and skills but if not take the cap and screw to a machinist and he can fill the hole and build up the missing boss with JB weld then drill and tap to the correct thread type. Alert him that this bolt hole is not under load and just to hold the valve cover on so does not need a helicoil or other advanced thread repair. Be sure to find all the pieces of the missing boss before reassembly. On assembly I would gently tighten till snug and it should hold enough to stop any leaks. I would also mark that bolt with red paint or nail polish or something to reminded you that it has been repaired and be gentle at that location.

 

I think it would be prudent to get a new cam cover, one because an epoxy repair ain’t the answer. I’d also want to pull the cover to see if and what other swarf dropped in the hole.

I imagine to root cause of the stripped fastener is not failure to clean off the oil but rather if you are like most shade tree mechanics you have an 18” clicker that goes from 0- 200 ft/lbs and try to use it for everything.

 

I don't think I can unfortunately (at least not without serious risk to the engine), as if I understand correctly, the components of the cylinder head are cast and machined together, so the tolerances of a spare cam cap would not match up.

Sadly, you are incorrect on the 18" clicker part, which is one of the more frustrating parts. I've got the full trio, a 1/4", 3/8" and 1/2". I was using the 1/4" at about 50% load. I witnessed how much my 3/8" over-torqued when doing the forks at 16.5 lb-ft and went and got a smaller wrench so I wouldn't break anything... as others mentioned in the thread, I should've done this one by feel though.

 

I have seen both done, a friend had one strip out and couldn't find a heli-coil so I gave him cover off a scrap engine I had and as far as I know it's still on the road today. I helped another friend install a heli-coil and it worked fine.

You have a unique situation. If you machine a flat surface on the cover maybe you could get a bolt with a longer shoulder or figure out how to permanently add to the shoulder bolt you have. If it's not permanent, as mentioned above I'd be concerned it may come off the next time it's removed.

Actually that threaded collar would work if you could machine it to the correct height and red loctite it on.

This is the reason I don't torque these bolts, I just hand tightened them.

 

If you were to glue a bolt/stud in the hole would you still be able to get the cover off ?

Doing a good job of securing a stud in place then using a nut to hold the cover on would stop any future issues

 

Reasonable repair idea. You might have to get some type of hat bushing to to get a seal on the gasket like the shoulder bolt does and some type of seal washer for under the nut, then you should be good to go

 

My thought was a bit of stainless pipe to make the shoulder, I have that laying around here so that was my first thought.

 

@jameshalberta
Let us know what fix you decide

 

Pull the journal cap and take it to a machinist and see if it can be repaired, whatever the method. If not then you either have to replace the cylinder head or just the journal cap.

I don't think I can unfortunately (at least not without serious risk to the engine), as if I understand correctly, the components of the cylinder head are cast and machined together, so the tolerances of a spare cam cap would not match up.

True but others have done this without issues so you aren't the first or a guinea pig proving this procedure. I don't think it is a serious risk but a testament to Suzuki's design and precise manufacturing that, based on actual results, journal caps are interchangeable. Suzuki doesn't sell journal caps independent of cylinder heads because of the small risk it won't mate properly and problem of machining one independent of a cylinder head.

These parts are machined to tight tolerances, i.e. a range of acceptable measurements, and you'd have to randomly mate a cylinder head on the low end of the range with a journal cap on the high end of the range or whatever combo causes issues. Just on random chance, that seems like an exceedingly unlikely outcome. Also, even if the donor journal cap fails you'd be looking at a new cylinder head and cams anyway if the damaged journal cap cannot be repaired. But replacing the cylinder head is a much more involved and expensive repair.