Advice needed on stripped intake bolt

[flatland]

While replacing my leaky intake gasket, things were going really well. Too well.

As I made my first torque pass at 20 Ft/lb, the rear passenger bolt stripped. There was a bracket under it so I removed the bracket and torqued it to 20 ft/lbs. My second pass to final torque at 30 ft/lbs went well on the first 11 bolts. I just couldn't convince myself to try number 12 again so it remains at 20.

Should I :
-run it as is and see if it leaks
- remove bolt and drill a deeper hole to extend threads and use a slightly longer bolt ( is this a blind hole , and how far can it be/should it be extended if it is?)
-remove bolt, drill and place helicoil ( again, blind hole so no shavings?)
-drill and tap to larger bolt
-remove intake first and then one of the above ( obviously necessary if hole goes through to lifter valley)

Also, retorquing after heat cycle is recommended, is this ok if thread sealant was used or will the sealing be compromised?

Thanks for any help!

 

[TJ1978]

Helicoil

 

[BoondocK5]

Helicoil

It is the only real repair. Should be relatively easy.

 

[flatland]

Is this end hole a blind hole that can be drilled with the intake in place without chips passing into the lifter valley?

 

[BoondocK5]

Need to do it with the intake removed. Only way to be sure…
I believe it is a blind hole, but, don’t have one in front of me to verify. Irrelevant though, every mechanically inclined person should be able to drill and install a Helicoil properly. Like everything else in this life, prep-work makes or breaks the deal.
Intake removal, clean up, stuff towels down every hole to keep chips out, lay towels into the lifter valley, same reason, use the proper size drill for the helicoil, drill straight for heavens sake, if it looks cock-eyed, it is. Clean out the freshly drilled hole with brake cleaner and compressed air, use a small dab of red lock-tite on the Heli-coil itself just a small drop. You don’t want it adhering to the intake bolt, just the Heli-coil.remove all paper towels, yeah I said it! New gaskets and reassemble the whole thing.
Do not over torque the bolt in the repaired hole.
Enjoy!

 

[Blue85]

Maybe this is optimism, but It's possible there's already room for a longer bolt and some more good threads down there you haven't reached yet. You could pull it and stick something down to measure depth. The end holes should be blind, while all of the center ones are open all the way through (although we don't know for sure which heads you have.) Too long of bolts in the center holes can hit pushrods. I found a source saying the end bolts should be 1.5" long and the center ones 1.25" long. You'll need to confirm this for your intake, but the point is that somebody may have mixed up fasteners at some point.

 

[Wes Harden]

I put sticky gease in the drill bit flutes when I need chip control.

 

[folkenheath]

While replacing my leaky intake gasket, things were going really well. Too well.

As I made my first torque pass at 20 Ft/lb, the rear passenger bolt stripped. There was a bracket under it so I removed the bracket and torqued it to 20 ft/lbs. My second pass to final torque at 30 ft/lbs went well on the first 11 bolts. I just couldn't convince myself to try number 12 again so it remains at 20.

Should I :
-run it as is and see if it leaks
- remove bolt and drill a deeper hole to extend threads and use a slightly longer bolt ( is this a blind hole , and how far can it be/should it be extended if it is?)
-remove bolt, drill and place helicoil ( again, blind hole so no shavings?)
-drill and tap to larger bolt
-remove intake first and then one of the above ( obviously necessary if hole goes through to lifter valley)

Also, retorquing after heat cycle is recommended, is this ok if thread sealant was used or will the sealing be compromised?

Thanks for any help!

If you got them all to 30 and that one to 20 just run it for now.

If you used teflon thread sealer it can take retorqueing.

Watch your oil on the dipstick, if you get any coolant in your oil it needs to be fixed fast.

If it turns out to leak then put a helicoil in at that time. I wouldn't take it apart just to helicoil it now while its working. I've surely installed intakes with much less than 30 ft-lbs, sometimes I have 3/8" ARP bolt head and I only use a 3/8" wrench as I can't get a socket on every bolt, I surely wasn't even at 20 ft-lbs with a 3/8" wrench. The key is to make sure it doesn't come loose. Check it for the first half a dozen heat cycles or so after it cools off, just re-snug it. Once they stop moving, they should stay tight from then on.

Intake bolts/holes are always something to triple check, some are blind, some are not, some enter the crankcase, some can enter the water jacket, and some will contact a pushrod if too long.

 

[flatland]

Maybe this is optimism, but It's possible there's already room for a longer bolt and some more good threads down there you haven't reached yet. You could pull it and stick something down to measure depth. The end holes should be blind, while all of the center ones are open all the way through (although we don't know for sure which heads you have.) Too long of bolts in the center holes can hit pushrods. I found a source saying the end bolts should be 1.5" long and the center ones 1.25" long. You'll need to confirm this for your intake, but the point is that somebody may have mixed up fasteners at some point.

I removed a bracket (3/16") from under the bolt and gained a bit

I put sticky gease in the drill bit flutes when I need chip control.

I'll remember this!

If you got them all to 30 and that one to 20 just run it for now.

If you used teflon thread sealer it can take retorqueing.

Watch your oil on the dipstick, if you get any coolant in your oil it needs to be fixed fast.

If it turns out to leak then put a helicoil in at that time. I wouldn't take it apart just to helicoil it now while its working. I've surely installed intakes with much less than 30 ft-lbs, sometimes I have 3/8" ARP bolt head and I only use a 3/8" wrench as I can't get a socket on every bolt, I surely wasn't even at 20 ft-lbs with a 3/8" wrench. The key is to make sure it doesn't come loose. Check it for the first half a dozen heat cycles or so after it cools off, just re-snug it. Once they stop moving, they should stay tight from then on.

Intake bolts/holes are always something to triple check, some are blind, some are not, some enter the crankcase, some can enter the water jacket, and some will contact a pushrod if too long.

Teflon thread sealer. I do believe it is blind. A very light bead of sealant under the gasket around the hole, but not on top.
I considered all the advice and had a helicoil kit in my cart to order. Then I decided there wasn't much to lose, so I torqued it to 30 Ft/lbs and it held!
I guess the additional thread engagement from removing the bracket was enough.
I don't think I can get to that bolt to retorque after everything is reassembled, so I plan to put it all back together. I will watch it closely and hope.

Now to finish all of the MAW things while I have more access. Reworking some wire harness loom, grounds, vacuum lines, cleaning, etc. I hope I can stop before a complete rebuild,lol.

THANK YOU to all of you for all the help!