TOPIC:

I recently had my head over to the shop for a very nice valve job, about $800 in p&l. During reassembly, I had a handful of cam cap bolts pop their threads. I went ahead and helicoiled them, and now a few of the helicoils are popping their threads as well, along with a keen-sert I had installed to repair an already busted helicoil. 
I've got two stripped helicoils and one stripped keensert. I can install new keenserts for the helicoil, I'm just not sure what to do with the stripped keensert issue, short of filling the hole with weld and tapping new.
Any sage advice to save this head?

Are you sure they are being torqued to the proper setting? The fsm  has a misprint in it. As I recall, the proper torque for them is 70- 80 INCH pounds.

The manual I have states 12 ft/lbs, which does seem a bit excessive.

The 900 manual calls out 95 inch pounds. The 1000 calls out 95-113 inch pounds. I know the experienced engine builders will use less. Hopefully they will post. 

wrote:

The manual I have states 12 ft/lbs, which does seem a bit excessive.

 

Yes, that is a misprint and that is why they were stripping out. Twelve pound feet is far too much for such a small bolt, especially when screwed into aluminum. If you look at the general torque table near the front of the manual, you will see much safer numbers. 

52-78 in/lb per the chart in the front, 1/3 to 1/2 of the torque called out. That's one heck of a misprint...
Now that I've got that figured out, what should I do about my stripped out keensert? Would it be a terrible idea to use a 10mmx1.25 helicoil and reinstall the keensert in that?

No eBay APP ID and/or Cert ID defined in Kunena configurationBefore you get into more trouble you need to post the diameter of the insert that failed. They are a special size and pitch so that could be where you went wrong. There's limited room so choosing the right insert is vital at this point. I had the same problem but with a bolt in the case. Went with a m8Xm6 insert as a m10 would have been the last resort and not much meat left in the case. Whatever you decide to use precision is required.
Steve 

Start at 8:19 

Follow the advice of SWest on this...
Got a M6 TimeSert Big-Sert kit for a couple cam-end plug bolt holes after Helicoils failed and pulled out.  Haven't needed it since, but it was the only logical repair system I could think of.
 
I always use clamps to pull the cam caps tight to the head, and then thread each bolt in by hand.  With each cap still clamped, I torque each bolt to spec.  Only then do the clamps come off.

 

wrote:

Follow the advice of SWest on this...
Got a M6 TimeSert Big-Sert kit for a couple cam-end plug bolt holes after Helicoils failed and pulled out.  Haven't needed it since, but it was the only logical repair system I could think of.
 
I always use clamps to pull the cam caps tight to the head, and then thread each bolt in by hand.  With each cap still clamped, I torque each bolt to spec.  Only then do the clamps come off.


 

^^This. The only time I stripped a thread is when I tried to pull the cam down using the bolts. You only have to make that mistake once. 

No eBay APP ID and/or Cert ID defined in Kunena configurationAlways appreciate your advice Steve. It is a keensert that requires an M10 x 1.25 standard thread



I'll also follow the advice of clamping the caps down first, just gotta figure out how. 
 

IS THERE ENOUGH MATERIAL?

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IS THERE ENOUGH MATERIAL?

There's just enough room to drill and tap M10.
It comes very close to the cam shells though so has to be accurate.
I've repaired many by fitting home made M10 steel inserts that i tap back to M6.