EDIT: Currently have two broken intake bolts, front two on the motor next to the coolant passages. About 3/8 of stud sticking out with intake off. Tried a stud extractor with no luck, it needs more space than I have because of brackets and so forth. Trying to pull the intake off a later 350. I had to wreck the distributor cap to get it off - apparently the bolts are either 5.5mm or like 13/64ths - a 7/32 socket would slip on it, a 3/16 too small, a 5mm too small, a 6 slipped easily. Then I broke the distributor hold down bolt - okay, intake is going anyways. Now, I get to the front four bolts. Second one back on the right came out more or less okay and was coated in oil. Front one on the right snapped off. Tried both left ones - second one does NOT want to move, front one moves a little but it's stiff enough I could be twisting it off too. I've been using just a 1/2 drive ratchet on most of these. The third bolt I've broken on this motor. I'm not sure the wax trick would work simply because the bolts don't go directly into threads - they pass through the smooth hole in the intake first. Access on this engine is a bitch because it's currently sitting in a van, so you're right under the damn cowl to try to work. I figure I can probably get away with the one broken bolt, but if I bust those other two, then what? Drill them out? Try to spin them all the way through, maybe in trying to drill them out, and pull the valve covers off to get the stubs out? Except I think the very front ones feed into coolant passages, so I'd have to try a magnetic tool to get the remains of the bolt out. I have more bolts, that part is no big deal. Oh, and of course the fun of drilling up a bolt over the open valley, so chances are no matter how careful I am to cover it a few pieces will get in the engine. Most of them came out easily, except one at the rear that I'm fairly certain was pulled before (this clearly had the trans replaced at some point and when it was put together they did a half-assed job). So I have to presume if they won't move, the threads are munged up somehow.
Just curious, is it an aluminum intake? I'm assuming you're going to use the motor in the van that it is in. Sounds like you are probably thinking like I am, that there is some serious corrosion/crap around the bolts where they go through the manifold. If it was/is an aluminum intake, the Appalachian in me would probably consider taking a BFH to it, if no other method worked to get the bolts out. I'm guessing the best option may be to drill them out as much as possible, and dealing with the stubs with the intake out of the way.
If I bust the other two off, the intake should pull right off. They're stuck where they thread into the head, they only pass through the intake. All that's holding it on right now are the two front left bolts and only because I'd rather break one than three. The problem then becomes holding the intake down again without it leaking all over the place - these bolts all are around the front coolant crossover. IIRC from the last one I pulled, the front ones do thread into the coolant passages. I suppose I could bust them, then try and clean them up with wire brush, then try the wax trick. FWIW, whatever else they changed with this new format, this thread already comes right up at the top of google searches when I look to see what other people have done. Getting so I hate fixing these things, every time to fix one $5 part costs $50 more because this breaks, that's in the way, and I need this, this, and this to do the work.
They are prob corroded in the aluminum intake. This means the head will snap off leaving about 7/16" of stud in the intake you will never get it off without drilling. I would try the hot wrench on the aluminum intake. A little heat can do wonders.
I would go with a big hammer or just break the heads off the final two bolts, then pull your intake off. Duck tape some shop rags together to put in the valley and then tape them to the heads, then drill a small hole into the top of the now broken bolts and use a puller tool. Not really sure of the name of the tool I just know you force screw it in to a bolt then when you go to back it out it will take the bolt with it. I would also spray what threads you can see with the intake off with some kind of penetrating fluid to help break up any corrosion on the threads in the block Posted using the Full Custom H.A.M.B. App!
Ah, I sense great amounts of frustration with these bolts, cuz I've read a lot of your posts here over the last few years, and I know you won't try to run without all the bolts. I think the HAMB's software is related to Google, and that may be why the HAMB posts come up first. I'm gonna Yahoo this just to see what happens there.
Not sure how else to say this but these bolts thread into the iron cylinder heads. The holes in the intake are plain. In fact, I went and looked at another engine with the intake off and bolts 3-10 thread right through into the lifter valley, so if one of those was to break you could just drill it and if it catches it will spin right through. Unfortunately 1, 2, 11 and 12 go into blind holes and it's one of those which broke. Every post where someone else has had this problem and tried an easy-out, they've broken it. I went out and got a propane torch and the damn thing won't even work if I aim it down, I don't know if something is wrong with it or they put some kind of tip over safety valve on the frigging thing. Nothing in the instructions. The flame first gets big and orange, then blows out.
If this is a Vortec motor (eight vertical bolts) I would just cut the heads off the stubborn ones and pry the intake off. Then weld nuts onto the remaining broken/cut bolts and back them out. Most likely the bolts are seized in the aluminum.
No welder. And frankly no good way to cut the head off either, the front of these drops down a little and the whole front of the motor has a steel accessory bracket on it that probably would mean breaking a bunch more bolts to remove. 2nd one on left came out, threads coated with oily crud. Found a way to hold the torch on the head of #1, heated it a few times, so far no dice and now the sockets want to jump off it. Everyone keeps saying "siezed in the aluminum" and I think I've said five times now there are no threads in the aluminum intake, only in the steel cylinder head. Not only that, but this one has a lift eye bolted under it so the head doesn't contact the alumimum either. The only other one that was difficult was the rearmost left one, also a blind hole, but someone had it out before - this vehicle had a trans swap at some point and the reassembly was sloppy, lots of loose bolts - and that bolt held a bracket in place that had to move to get the trans out. So the threads were full of rust. I mean I suppose it could be possible, but the fit through those holes is loose.
I'd use a torch, heat the bolts up cherry red, quench them, repeat a couple times. Hopefully it will get the part of the bolt down in the heads hot enough to loosen the rust. Then try tightening them a bit, then loosening.
Pried intake off. About 3/8 of stud sticking out of both iron heads. Thinking I need to try a stud extractor on them. Not sure I can hit them with the propane torch because it flames out at downward angles. Don't have a real torch here. I did this at home so I'd have access to another vehicle to run parts in, that's legal to drive... should have done it in the shop I guess.
Hate to bring this up, but your fix may end up being removing the heads to work on the intake bolts, and then replacing them after they're repaired. As for the "stuck in aluminum references that guys have made....they can still be bound up in the intake, even if the intake is simply a pass through. The close tolerances can allow corrosion around the shank of the bolts that sticks to the aluminum intake.
I am not sure if using a propane torch is getting enough heat applied to the bolts ,and or head area to do the job,you need Oxy Acy to put some serious heat to the area.
Oddly, the head of the second bolt that broke is pretty well welded into the engine lifing ear. Never saw that before. If the heads have to come off, screw that, I'll look at getting another motor at the you-pick yard. I can just see more broken bolts coming, probably stuff that holds the accessory brackets on the front of this thing.
I agree with the heat method. Getting the bolt hot while head is still reasonably cool often breaks the seal between the 2 parts. It's easier to spend a little time removing the bolts before they snap off in stead of the hours needed to remove the remnants of the bolt. Good luck. I have removed hundred of 3/8" exhaust pipe studs using the heat method. Some were so thin from the rust that you would not believe that they came out.
As 1971BB427 said, a bolt that passes through the un-threaded manifold hole can easily be siezed. I just finished fighting the same thing getting the Camaro-tranny-cocking bell housing off a T5 I'm putting in my `63 C10. I threw eveything I knew at it: WD40, Liquid Wrench, Gibbs Penetrating oil, propane torch, wax, heat and quench. Even after destroying the threaded area of the bell around the bolts they were still siezed on the shank of the bolts where they pass through the trans ears. This T5 was from upstate NY....ahhh life in the rustbelt.
aluminium and steel don't get along, even though the intake manifold is pass through the aluminium oxidizes around the steel bolt. Propane ain't gonna cut it, won't get near hot enough. Oxy/Acetylene and a stud puller.
It's too late now, both bolts are broken off with about 3/8 of stud sticking out. I tried a Harbor Freight stud puller, but it seems to need more room to spin around the stud to grab it. Thinking I may try the type that works like a drill chuck. Or maybe I should just knock one of them off, slap the thing together, gook up the coolant passage with some extra RTV, and say screw it. The intake has 10 other bolts holding it down, it's not going to fall off.
Mapp gas will get things hot enough but soak them with 50-50 mix ATF/ACETONE first and be patient. couple rounds of this and they will usually back out. someone could have used loc-tite and heat will release it!
Had some pistons frozen in a junkyard 348 score once. Tried everything named above. Only thing that did work was white vinegar and a bfh. Slowly pour the vinegar on the top of the bolt, make sure the vinegar is going down the threads and let it set 24 hrs and put some vice-grips on whats left of the bolt and try to coax it out while tapping on the top of the bolt with something.
If you leave the broken bolts, it will leak. RTV will not seal it properly, you need the clamping force of the bolt. If you have some of the broken bolt sticking out of the head now that the intake is off, get a nut that will slide over the stud and drop it on. Then weld the nut to then stud with a ton of heat, wait a few seconds till it stops glowing and get a wrench on it and spin it out. The heat from welding will generaly free it up. I use this method on a regular basis at work and it very seldom fails me. Good luck.
HEAT....I use my torch.. heat the cyl head around the broken bolt squrt with some pb blaster, grab with some vise grips work it back and forth and it should come right out, might take a few heat cycles, but it will come out.
I was taught by a helicopter mechanic during the Honduras event to first tighten to the torque limit then loosen to about the torque. Repeat many times. What you are doing seems foolish but you are flexing the offending fastener in a rotation bit by bit and eventually you'll get to the bottom and it'll come out. Righty tighty lefty loosey over and over.
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