Advice Needed: Broken / Trapped Manifold Stud Fragments

[SSTJ]

First image below is from the FSM, and gives the numbering that I'll use in this post.

Second and third images are a look inside the threaded hole for #7. Fourth and fifth images are a look inside the threaded hole for #6.

Looks like whoever last worked on my manifold snapped the original studs and decided to just cram the fragments as far back as possible. That would explain why I didn't find studs in #6 and #7, but rather some bolts, as I described here.

Right now I still have about 1/2"–5/8" worth of thread in the holes. I could get by with that for a while I suppose, but this isn't ideal. What to do? Does one drill these out, or would it involve opening up the head to pull them out from the back, or what? This is the furthest I've ever ventured in my engine bay.

 

[Jeepr89]

They make drill bit guides that your could use. It would protect the threads.

 

[someguysjeep]

if they are fragments you should be able to use a pick and get them loose and draw them out with a magnet.
there is no way they snapped off studs and then they somehow turned sideways and lodged unless it had been drilled and had room to collapse and wedge.

if a pick can't get some wiggle on the pieces a drill might eat enough to get some relief, a drill guide like mentioned above or even just a small piece of metal tubing would work to protect the threads.

 

[SSTJ]

if they are fragments you should be able to use a pick and get them loose and draw them out with a magnet.
there is no way they snapped off studs and then they somehow turned sideways and lodged unless it had been drilled and had room to collapse and wedge.

if a pick can't get some wiggle on the pieces a drill might eat enough to get some relief, a drill guide like mentioned above or even just a small piece of metal tubing would work to protect the threads.

Great point. They do look like fragments, so maybe they can be picked loose.

 

[someguysjeep]

Great point. They do look like fragments, so maybe they can be picked loose.

more likely they busted um drilled um couldn't get the fat side out of the threads and it didn't break loose until the inbound bolt crushed it loose and rammed it down.

could even try a few taps with a punch or screwdriver to maybe loose it.

 

[Gilaguy23]

It looks like you should be able to pick the bits out or use air or a magnet while poking around.

 

[someguysjeep]

It looks like you should be able to pick the bits out or use air or a magnet while poking around.

that bit you deleted, is it possible?
is that the break into the water jacket in 6 n 7 mentioned in the other post?

 

[SSTJ]

Ok, I have tried picking around with my tiniest screwdriver. I think I'll have to dry drilling with a drill guide. Googling those now.

But let's say I manage to break these fragments up into smaller pieces with the drill bit. If I also accidentally push them further back, is that a problem? I don't yet understand the water jacket very well, and I wonder what trouble I might cause if any of these little pieces fall back there.

 

[Jeepr89]

Measure how deep one of the other holes is and mark your bit with tape so you don’t go too deep.

 

[someguysjeep]

if a pick can't show sign of movement..........rather than a costly mistake..........why not leave um alone and make up some 7/16 studs (that's what they opened the holes to , yes?) and use some high temp sealant. 1/2-5/8" deep engagement should hold.

 

[SSTJ]

if a pick can't show sign of movement..........rather than a costly mistake..........why not leave um alone and make up some 7/16 studs (that's what they opened the holes to , yes?) and use some high temp sealant. 1/2-5/8" deep engagement should hold.

Yea, that may be wise. I could pick up some shorter 7/16" studs and use those I guess.

If I take that approach, how do I torque down the studs in the first place? I've never done that before. Or does the sealant do most of the job at holding it in place?

 

[SSTJ]

Measure how deep one of the other holes is and mark your bit with tape so you don’t go too deep.

Thanks, but my worry is that these holes (allegedly) open up in the back to the water jacket. I'm afraid that if I drill these bits into smaller pieces, those smaller pieces may slip through the back. I'm wondering if that's a big deal or not.

 

[someguysjeep]

studs would be just threaded rods.
you'd have to double jamb some nuts onto the end and turn them in tight then you break the nuts loose remove them and you have your stud.
you could also just use a bolt. put those bolts into the holes until you feel them bottom if they stick out further than the thickness of the manifold plate cut them back just a bit until they stick out a hair less than the manifold plate thickness.
if sealant is recommended there use it. as for torque, good and snug should work until it proves otherwise.

 

[SSTJ]

studs would be just threaded rods.
you'd have to double jamb some nuts onto the end and turn them in tight then you break the nuts loose remove them and you have your stud.
you could also just use a bolt. put those bolts into the holes until you feel them bottom if they stick out further than the thickness of the manifold plate cut them back just a bit until they stick out a hair less than the manifold plate thickness.
if sealant is recommended there use it. as for torque, good and snug should work until it proves otherwise.

Gotcha.

Yep, I am in a pinch right now, so I am going to use bolts. Will torque to the spec of the nuts that are supposed to go on the studs. When I have more time (I didn't anticipate this kind of problem in planning/timing this job), I'll try harder to get those fragments out. And if that fails, I'll take your suggestion of putting new studs in, using the room that's left in front of the fragments.

Edit: PS, @someguysjeep, that's a good point that the reason my #6 and #7 are 7/16" may be due to someone opening them up after drilling out the broken, original studs. If that's true, then even if I get these fragments out, I'm going to have to tap the rest of the hole to match the 7/16". So, yet another reason that I'll have to save this for another project, and will just use shorter 7/16" bolts for now.