I was removing the cylinder head on my 73 (the kids have named it the Pickle) FJ to replace the freeze plug between the head and the firewall. I sheared off one of the head bolts. When I removed the head, there was about an inch of the bolt showing above the block. I've read several posts about heating, soaking (I use Kroil by day and squirt it with some PB Blaster at night) in penetrating oil, torquing slightly and then repeat. My neighbor thinks that I should be using a more powerful heat source. I'm using a Propane torch that I bought at the local parts store. He feels I should try to tow it down to his brake shop so that we can apply a hotter source to the engine block. I'm also confused with some posts that say to heat the block (not the bolt) and then others say the opposite (heat the bolt so that the heated part will draw the penetrating oil into the threads. thanks in advance for your help. I've attached a couple of pictures of the stubborn bolt. I've been repeating this process for about 2 days now after I get home from work.
Cylinder head bolt extraction (73 Pickle)
- Thread starter debkev1010
- Start date
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Weld a nut onto the remains. Pour the heat on it so that the bolt gets red hot deep in the block. When it cools the metal shrinks, making it easy to turn out. Everyone that owns a cruiser needs a welder. If you can't weld it, you can't fix it.
It looks like it might have started to strip out, so if it did, a Helicoil or other thrread repair is in order.
It looks like it might have started to strip out, so if it did, a Helicoil or other thrread repair is in order.
Looks like it has been very kind to you by leaving a good amount of bolt to grip onto (with vicegrips).
Whatever you do, don't try heating the block because doing that will cause damage.
Heat the remains of the bolt (as you have been doing) except I agree that oxy-acetylene would be better than air-propane (which is not really hot enough).
Heat it to dull-red (or close to that) and then try undoing it again.
If it is still reluctant to let go, quench it with penetrating oil and repeat.
(Of course you'll never get the section of the bolt that's threaded into the block to "dull red" but your "heating and cooling" tends to break the bond between the male and female threads.)
Whatever you do, don't try heating the block because doing that will cause damage.
Heat the remains of the bolt (as you have been doing) except I agree that oxy-acetylene would be better than air-propane (which is not really hot enough).
Heat it to dull-red (or close to that) and then try undoing it again.
If it is still reluctant to let go, quench it with penetrating oil and repeat.
(Of course you'll never get the section of the bolt that's threaded into the block to "dull red" but your "heating and cooling" tends to break the bond between the male and female threads.)
You need to heat the steel above the austenitic phase transition temperature in order for it to shrink. This temperature is about 1375V (750C), when the steel is cherry red. You can tell that it is hot enough if a magnet won't stick to it.
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Now I would be thinking that a force a lot stronger than simple rust between the bolt and block would have to be holding that stub for it to have broken before unscrewing in the first place.
In the worst case scenario, it is good to know a helicoil kit does exist for this situation.
Best
Mark A.
In the worst case scenario, it is good to know a helicoil kit does exist for this situation.
Best
Mark A.
bsevans
Focus on the Journey
HeliCoil does not make an M13 by any pitch insert. Maybe some other company makes an insert, however HeliCoil does not.
Yep weld a nut on the end. Then heat and then reheat a few cycles like stated above. Us an impact gun to remove. Apply a little pressure at a time.
IMO your block surface looks to be in pretty rough condition.
IMO your block surface looks to be in pretty rough condition.
left hand thread die
If you dont have a welder I am thinking you could buy a left hand thread die and thread the top. Put 2 nuts on it and turn it out.
I dont recommend easy outs on engines cause if they break you will be going to the machine shop to get them removed
I might have tried Vice Grips but if you mess it up you might be limiting other options so some risk
Normally heat and oil do the trick though---and patience
If you dont have a welder I am thinking you could buy a left hand thread die and thread the top. Put 2 nuts on it and turn it out.
I dont recommend easy outs on engines cause if they break you will be going to the machine shop to get them removed
I might have tried Vice Grips but if you mess it up you might be limiting other options so some risk
Normally heat and oil do the trick though---and patience
