Stripped cam cap bolt hole/ Not fun. Thoughts

[n2osx]

So my '04 has 111,000 and I was just putting everything together after I adjusted all of the intake valve that all were too tight. I lubed everything up really well. Installed the shims and buckets. Sat the intake cam back in it's correct place. Triple checked that the cams were where they were supposed to be even though I put a zip tie near the crank and one on each cam gear. I sat the caps in their correct places and hand tightened the bolts in their back and forth order. As I was about to start the rest of the tightening sequence, 2 of them got to maybe half way to the 88 inch pounds and stripped out. I have used Heli Coils all my life and was thinking about using the Timesert. Problem is, is that the cam cap has a sleeve that fits into the head and the size of the drill bit a and tap may end up being bigger than the cap sleeve. I am going to measure to find out, but I figured that I would ask if anyone here has stripped one of these out?

Here are a couple picks. On the right hole from the cam, you can't see the threads because they came out with the bolt.

https://i33.photobucket.com/albums/d51/n2osx/Mobile%20Uploads/20150420_235309.jpg

Cap

https://i33.photobucket.com/albums/d51/n2osx/Mobile%20Uploads/20150420_235536.jpg

Bolt with threads that came out

https://i33.photobucket.com/albums/d51/n2osx/Mobile%20Uploads/20150420_235820.jpg

Thanks guys,

Carl

 

[JamesK]

Carl, sorry about your troubles, that totally sucks.

I was wondering if in this case maybe it's better to simply tap the stripped out holes with the next size up thread (tap) and use the matching bolts?

 

[yamafitter]

I have not stripped these bolts but have a couple of concerns about just drilling out and tapping to the next bolt size. The sleeves on the bottom of the caps perform an important function in properly aligning the cap since this forms a bearing surface for the cam to run on. If the drilling affects the locating sleeves you will be in trouble.

You will have to carefully measure the depth of the hole in the cylinder head to see if you need to modify either a helicoil or timesert to match so that the cap seats properly.

You may want to ask a decent automotive machine shop for an opinion on the best way to proceed.

 

[RossKean]

Stripped at 88 in-lb? That's only 7.3 ft-lb - maybe its time to check your torque wrench calibration. Good luck with the fix.

 

[RaYzerman19]

Agree with Bill, as alignment of the cap is critical........ and I would consult a machine shop as they have likely seen it before. The cylinder head could get an insert most likely, which would preserve the cap sleeve. Failing that, as a last resort if you did have to drill a cap, the drilling should be absolutely centered in the old hole (i.e., hand held drill not the best idea). If you did happen to lose the sleeve, it's not the end of the world. Snug up all the cam caps, including the one good side of the drilled cap, give it a wee tap to ensure it's seated, and it should self-align on the cam bearing surface. Then install the larger bolt on the drilled side.

Another idea, not the ideal, is to switch to SAE thread on that particular bolt. I don't know the size, but perhaps there's an SAE size that is slightly larger that can be tapped, and still preserve most of the cam cap sleeve?

 

[08FJR4ME]

Make sure you check the thread pitch if using another oversize bolt. you don't want it to vary much or you will be in trouble again.

Dave

 

[FJReady]

How much virgin metal is there at the bottom of the hole? Is there a possibility of drilling and tapping the hole deeper and using a longer bolt?

 

[Constant Mesh]

I would expect that the recommended 7.4 ft lb of torque would be assuming oily threads are in play.

That's not much torque.

 

[Geezer]

If you are going to pull the head off to take it to a machine shop, it might be time to look into a replacement head rather than screw around fixing that one.

 

[n2osx]

Thank you everyone for all of the replys.

I have not stripped these bolts but have a couple of concerns about just drilling out and tapping to the next bolt size. The sleeves on the bottom of the caps perform an important function in properly aligning the cap since this forms a bearing surface for the cam to run on. If the drilling affects the locating sleeves you will be in trouble.You will have to carefully measure the depth of the hole in the cylinder head to see if you need to modify either a helicoil or timesert to match so that the cap seats properly.

You may want to ask a decent automotive machine shop for an opinion on the best way to proceed.

This is one thing that I was really worried about too. I thought about seeing if I could find bigger sleeves to insert after fixing the threads.

Stripped at 88 in-lb? That's only 7.3 ft-lb - maybe its time to check your torque wrench calibration. Good luck with the fix.

It is a borrowed Torque wrench (my good one grew legs and walked away...) so I tested it on the SnapOn Truck first and it is correct.

Agree with Bill, as alignment of the cap is critical........ and I would consult a machine shop as they have likely seen it before. The cylinder head could get an insert most likely, which would preserve the cap sleeve. Failing that, as a last resort if you did have to drill a cap, the drilling should be absolutely centered in the old hole (i.e., hand held drill not the best idea). If you did happen to lose the sleeve, it's not the end of the world. Snug up all the cam caps, including the one good side of the drilled cap, give it a wee tap to ensure it's seated, and it should self-align on the cam bearing surface. Then install the larger bolt on the drilled side.Another idea, not the ideal, is to switch to SAE thread on that particular bolt. I don't know the size, but perhaps there's an SAE size that is slightly larger that can be tapped, and still preserve most of the cam cap sleeve?

I was thinking about trying this though I was thinking that modifying or removing the precision sleeves would land me in trouble.

How much virgin metal is there at the bottom of the hole? Is there a possibility of drilling and tapping the hole deeper and using a longer bolt?

I don't think that I would want to chance it for fear of running into the top of the cylinder chamber.

I would expect that the recommended 7.4 ft lb of torque would be assuming oily threads are in play.
That's not much torque.

If memory is correct, something felt a little off when I pulled those 2, like half tight and pull out 99.99% with fingers.

If you are going to pull the head off to take it to a machine shop, it might be time to look into a replacement head rather than screw around fixing that one.

I was thinking the same thing. I am hoping not sense I am pretty poor these days. Granted, I found a few as I was looking last night for $225-$250 which isn't bad but still a little painful at the moment.

Thank you so very much everyone!

Carl

 

[Fred W]

I have one other possible solution for you that would be quicker and easier. And if doesn't work out you can always go with one of the other plans The caveat is that I don't know if there is enough room inside the valve cover for doing it.

You could buy some appropriate sized threaded rod and cut a piece just long enough to be inserted and used as a stud with a nut on top of the cam cap. You'd need the stud length to be just long enough for the nut and not have much stud sticking out above it. The threaded rod would be threaded down into what is left of the threads in the head and then secured with some type of heat tolerant adhesive.

The torque on those cap screws is pretty small. I've honestly never tried to use a torque wrench on one, just tightened them gingerly with a 1/4" drive (very small) ratchet.

 

[Panman]

I vote for Fred's idea. Clean the heck out of hole and cut some good all thread to the correct length and put some Loctite® Epoxy Weld™ Bonding Compound on the threads. Thread it in and let it sit a couple of days before you tighten things up.

https://www.loctiteproducts.com/p/epxy_weld_t/overview/Loctite-Epoxy-Weld-Bonding-Compound.htm

 

[dcarver]

Remove head. Weld. Drill. Tap. Done, professionally. Sorry to hear.

BTW, removing the head is a royal PITA.

 

[n2osx]

I have one other possible solution for you that would be quicker and easier. And if doesn't work out you can always go with one of the other plans The caveat is that I don't know if there is enough room inside the valve cover for doing it.
You could buy some appropriate sized threaded rod and cut a piece just long enough to be inserted and used as a stud with a nut on top of the cam cap. You'd need the stud length to be just long enough for the nut and not have much stud sticking out above it. The threaded rod would be threaded down into what is left of the threads in the head and then secured with some type of heat tolerant adhesive.

The torque on those cap screws is pretty small. I've honestly never tried to use a torque wrench on one, just tightened them gingerly with a 1/4" drive (very small) ratchet.

Fred, I was thinking about that as well having done it on other things. Especially after reading your post and then just a few minutes ago getting a call from a questionable yet very trusted friend

, I am going to try this route. If all else fails, I got wind of a great deal on another head.

Carl

 

[hppants]

I'll throw in another choice - I have the cylinder head from Patriot's old motor, lubed up and bagged nicely in my attic. Since I disassembled the motor, I can state with 100% certainty that the cam cover bolt thread are in good shape. Cam cover and cam cover bolts are also in good shape.

You can have it for the low price of FREE - shipping excluded of course.

Ask and ye shall receive.

 

[n2osx]

I'll throw in another choice - I have the cylinder head from Patriot's old motor, lubed up and bagged nicely in my attic. Since I disassembled the motor, I can state with 100% certainty that the cam cover bolt thread are in good shape. Cam cover and cam cover bolts are also in good shape.
You can have it for the low price of FREE - shipping excluded of course.

Ask and ye shall receive.

And this is yet another reason (among MANY) why I love this group. Thank you hppants! The other offer that I received is exactly the same, just a lot closer that I can drive to. from another forum member that I have known for a long time. Lets reserve the one that you have for another sorry sap that needs it.

Thanks again!

Carl

 

[RaYzerman19]

Well, before I went to all the pain of pulling a head, I would try other alternatives first........ what have you got to lose? As far as losing the alignment sleeve on one side of the cap, don't sweat it too much. As long as you preserve the other one, and drill out the other side centered, the cap will really self-align when snugged down to the cam bearing since it is such a tight fit....... machining guy should be able to drill out the head in place or ream in small increments, then tap for the oversize or the insert (your choice)........ 'jes sayin', huge job pullin' the head.

 

[rPGoatBoy]

Fred W's solution also has the added benefit of not precluding the possibility of a timesert / helicoil / machine shop repair in the future. That would be the route I'd go before swapping heads, with respect to hppants' generous offer.

 

[dcarver]

Oh, come on. He needs the wonderful opportunity to learn how fun it is to swap a head!