Survey: How many head bolts did you break off?

[Bryan]

Okay:  I managed to break 2 today.   Was wondering, how many head bolts did YOU break off taking the original head off of your flathead?   Don't include taking a head off of a recent rebuild.      Bryan - 2

[Sniper]

zero, but I tightened them first

[keithb7]

Just one.
 

I center punched it. Drilled it. Tried various bolt extractors. Nothing worked for me. I let the machine shop take over. They had no issue getting it out. 

[Bryan]

1 minute ago, Sniper said:

zero, but I tightened them first

Yeah, did that too, with tapping, heating, oil, tapping,  still broke. How much does a machine shop charge these days to remove a bolt?  

[Mark D]

55 minutes ago, Bryan said:

Okay:  I managed to break 2 today.   Was wondering, how many head bolts did YOU break off taking the original head off of your flathead?   Don't include taking a head off of a recent rebuild.      Bryan - 2

only one, the last one I tried… %^*+#€@

[Sniper]

55 minutes ago, Bryan said:

Yeah, did that too, with tapping, heating, oil, tapping,  still broke. How much does a machine shop charge these days to remove a bolt?  

I don't know, but I have two manifold bolts I'll be paying to have removed.

[oldodge41]

0 but I was really close to snapping a couple on the original D19 engine. Also 0 on a couple other flatheads but they had been apart in the last decade or so.

[Young Ed]

I have one flathead with a broken head bolt. But that also sat outside on the ground long enough that the entire bottom of the oil pan rusted off. So it's just stashed as a builder. My 47 truck engine I broke a water pump bolt off where someone had installed way too long of a bolt. I fought with it for hours with heat and going back and forth and it still broke. A $20 into the pocket of the machine shop owner and he had it out in no time. 

 

[kencombs]

I've never broken a head bolt, out of literally thousands on many different engines, OHV and flats.  Can't say the same for manifolds though.  But, I never use non-power wrenches for removal.   A little forward rat-a-tat first makes a big difference, then reverse a little, repeat until it comes out.   Most folks don't realize that air impacts are adjustable power, but only forward.  so you can control the power with the dial for installing, but you always have full power in rev.  So you have to be careful not to hold it down for too long, or it will break the bolt, assuming it is powerful enough, and mine is..  And, the old acetylene torch helps.  Cherry red head and cool almost always works. 

 

Having written that, the very next one is likely to break, flush with the block, on the back of an engine still in the car.  Things just happen like that.

[Sniper]

30 minutes ago, kencombs said:

Things just happen like that.

 

Especially when you have 13 letters in your last name like I do, lol

[LazyK]

zero head or manifold bolts broken off. car sat from 1986 till 2017. not sure when the cooling system was drained while it sat, or if the coolant just evaporated over time.

[Bryan G]

The last time I had to have a head pulled I was too nervous; I paid someone else to do it. He broke one. When I did my straight 8 earlier this year I decided I had to give it a whirl. I did a lot of praying (and I'm not kidding!) and I gave an extra bit of praise when that last bolt came out. That engine was apart sometime in the 80s, I believe, so I guess that helped.

[JBNeal]

using the tighten then loosen method, I broke zero head bolts on 6 different flathead engines over the years...though on my first flathead, I snapped a couple of manifold studs, and felt shame...

[Bryan]

Now I should probably ask, how many tried to drill it out and broke the bit off in it?   Only did that in the late 70s on a Camaro.  Probably will leave these for the machine shop.  ?

 

[JBNeal]

I have used an O-A torch to melt out the broken bolt in cast iron threads before...kept the flame tip on the busted bolt, and eventually it mostly flowed out, then cleaned out the threads with a tap

Edited November 24, 2021 by JBNeal
put back letters that fell off the page

[Sniper]

Might have to try that tip, have to get an O-A torch though, wonder if a Mapp/O2 torch will do it?

[JBNeal]

I picked that up from a veteran welder, his advice was to take plenty of time to setup so that the slag will flow out of the bolt hole by gravity, and even more to let the cast iron cool to the touch before cleaning the threads...the cast iron will dissipate the heat in no time as its mass is much higher than the slag, so no need to speed up the process by quenching, which might weaken the cast iron. If the slag has to be blown out, cover the surrounding area with some kind of steel or aluminum plate so the slag turns into b-bs quickly, have a magnet nearby to collect that slag if ya can.

[Bryan]

26 minutes ago, JBNeal said:

I picked that up from a veteran welder, his advice was to take plenty of time to setup so that the slag will flow out of the bolt hole by gravity, and even more to let the cast iron cool to the touch before cleaning the threads...the cast iron will dissipate the heat in no time as its mass is much higher than the slag, so no need to speed up the process by quenching, which might weaken the cast iron. 

I thought there is a danger of cast iron cracking if it cools too fast. Brother was telling me that about old wood stoves.

[Bryan]

When my exhaust manifold cracked in half, I had put very little pressure on it with a fence stake behind it on both ends. Just wagging both ends alternately, not hard, and it cracked.

[kencombs]

2 hours ago, Bryan said:

I thought there is a danger of cast iron cracking if it cools too fast. Brother was telling me that about old wood stoves.

That's true if you heat a large part of the block or head, but using a torch as described only heats a very small area, so no problems

[kencombs]

3 hours ago, JBNeal said:

I picked that up from a veteran welder, his advice was to take plenty of time to setup so that the slag will flow out of the bolt hole by gravity, and even more to let the cast iron cool to the touch before cleaning the threads...the cast iron will dissipate the heat in no time as its mass is much higher than the slag, so no need to speed up the process by quenching, which might weaken the cast iron. If the slag has to be blown out, cover the surrounding area with some kind of steel or aluminum plate so the slag turns into b-bs quickly, have a magnet nearby to collect that slag if ya can.

 

I've done the same and I can tell you that it is usually a bad idea to hit the O2 lever when the content of the bolt hole is molten unless you have the correct protective clothing on.   DAMHIKT!  When Dad had the salvage we had several occasions to correct previous owners mistakes.

 

I also had a flathead Ford explode when I got the oil pan too hot and the fumes lit off.   Pan bolts covered by the oil pan being bent in the wreck and I thought a torch would be a good solution.  17 YO, what can I say.  Lots of smoke and flame out of the fuel pump hole.  Right into my face!  Lucky for me the goggles where large and fit well!   I looked like a racoon negative, white around the eyes and black everywhere else.

[kencombs]

3 hours ago, Sniper said:

Might have to try that tip, have to get an O-A torch though, wonder if a Mapp/O2 torch will do it?

Not enough heat, especially with the new gas that replaced the original MAPP.