Cast iron heating question

[Dan]

I am putting on my flame proof suit now, so fire away if needed. But, I figure the only stupid question is one that is not asked and I am dealing with a rare original 1939 9N block here - so...

As many know, I have several head studs snapped of in the block I am removing. Penetrating oil just pools on top for days and is not seeping down in the threads. My thoughts are to use a propane torch to heat up the side of the block on the studs that are close to the edge to get it to expand and hopefully let the oil thin out and seep in. However - this requires holding that propane torch in one spot on the block for about 5 minutes to heat that area up enough to start seeing bubbles around the edges of the stud and block (a good sign). In doing so, I wondered if localized heat for a long period of time would damage the cast iron block - so, will it?

TIA,
Dan

 

[souNdguy]

I can't tell ya if it is wrong or right.. but i have done it.. Not head studs.. but broke bolts in castings, and other cast iron parts on shafts and splines that i heated the outside to get them to expand to beat them off. So far, no problems yet. good luck.. If your wrong, I'm wrong too.. so we will at least be in good company.

Soundguy

 

[Bob]

You CAN'T hurt that block with a "plumber's propane torch".

Likely, you can't get it HOT enough to help much, either.

 

[Dan]

I kinda figured that - but was not sure. Using a propane torch on old iron is tedious and time consuming for sure - but I found with enough time a patience it does help, probably not as much as a big torch.

Thanks,
Dan

 

[Westwind]

Dan - Think about this. The steel industry uses cast iron ladles to pour molten steel out of and they last for years. I'm absolutely certain you will not hurt the cast iron with a propane torch. You simply can't get it hot enough. In fact, I've seen guys use a cutting torch to blow out steel bolts broken off in cast iron. I don't know enough about it to tell you how it works, but I've seen it done. Just my .02 worth. Wish I could be of more help.

Wes in MI

 

[Bob]

Drill a small hole though the bolt, heat the bolt red hot with the smoke wrench, tap the oxygen lever, and the bolt's gone.

I still wish he could try the "weld a washer to it trick", though!

 

[Anonymous-0]

Be very careful and try the weld a nut to the top end of the broken stud idea. Leave it rest until cool and then try to move the stud. I have found that heating the casting and allowing it to completely cool then removing the broken threaded stud works very well. Don't try throwing any water on it to make it cool faster as it won't work. I think welding the nut to exposed end heats it enough to allow it to be removed. DON'T RUSH THE COOLING!

Remember once you screw up that block you will be regreting it for a long time.

 

[hunting4junk]

I worked in an engine remanufacturing facility for several years when we had bolts broken off in the cast blocks or heads our first plan of attack was to weld a nut to the broken bolt and then melt some parifan wax on the hot bolt. wicks down the threads and acts as a lubricant) if this didn't work we would normally drill them out then heat em up and wax again,and then put an easy out on them. we found that when possible drilling all the way thru a broken bolt we had better results. my theory is that by drilling all the way thru and then heating, the bolt will actually contract more after cooling than if you only drilled 1/2 way thru thus reducing the amount of thread engagement and allowing it to loosen easier. The parifan wax trick really works and it doesn't burn off and stink like most penatrating oils

 

[TheOldHokie]

(quoted from post at 09:11:57 09/12/07) Drill a small hole though the bolt, heat the bolt red hot with the smoke wrench, tap the oxygen lever, and the bolt's gone.

Tried that last night on an old N block with no success. Top half of the stud went first try but seemed like it was impossible to get the bottom half hot enough. Any words of wisdom?

TOH

 

[Anonymous-0]

If you can not get them to come with heat try welding a flat washer to the stud first then weld a nut to the washer I have found it to be better than trying to weld through the center of a nut.
If all else fails just drill through the exact center of the stud and use progressively larger bits to remove most of the material and dig the rest out with a sharpened punch or burn it out with an oxy-acetelene torch.

 

[JMOR]

Yep! Weld nut, let thoroughly self cool, screw it out...works time after time! Beats all the other methods I've ever tried or witnessed!

 

[Dan]

Thanks for all the replies - I figured it was ok, but as soon as you don't ask I usually screw something up.

Dan

 

[mhb@ufe]

(quoted from post at 09:46:10 09/12/07)

(quoted from post at 09:11:57 09/12/07) Drill a small hole though the bolt, heat the bolt red hot with the smoke wrench, tap the oxygen lever, and the bolt's gone.

Tried that last night on an old N block with no success. Top half of the stud went first try but seemed like it was impossible to get the bottom half hot enough. Any words of wisdom?

TOH

hat size hole did you drill. I try to drill as large as possible and if I'm off center at all I torch the thicker side of the remaining stud.

 

[TheOldHokie]

Yep - that was my first thought - I only drilled it out to 3/16". If I get a chance to play I'll try something more aggressive. You get a LOT of blowby back out the water jacket openings - quite exciting - got to watch your eyebrows :lol:

TOH