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some fu$%#ng retard put a bolt in the water pump mount on my amc 360 that was too long..... it made a 1/2 inch crack in the block that goes into a water jacket.....
if i use the die grinder and make a little "ditch"along the crack, could i mig it?... it looks easy, but i dont want to [email protected]# anything up..
James
 

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Welding on cast iron is a general no-no. If it absolutely needed to be done a stick welder with a nickle rod and a pre-heat are required.

JB weld may also work or some kind of high strength high heat epoxy.
 

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Blocks are tricky to weld, and if it fails will dump coolant. Some people may have the resources and skill to do it and have confidence in it holding, but I don't - and if you're talking about mig then you probably don't either.

Epoxy.

Shell Epon 828 + Henkel Versamide 140. Available here. Epon 828 has an equivalent weight of 180 and the Versamide is 140, so mix it 9 parts Epon to 7 amide by weight. Fill it with 5-micron aluminum to make a thick paste (available here.) Stir it vigorously for at least 3-4 minutes, and if you can arrange to degas it afterwards (ie. pull a vacuum under a bell jar or in a desiccator, etc.) by all means do.

I've patched blocks with JB Weld before, with good results, but the recipie above is much better. Clean everything good with brake cleaner first, and give it 24 hours to cure - try to keep it near 70F or above while it cures, at higher temps it goes faster, and UV light helps too. I know of one JB Weld patch (engine block through to cooling jacket) that held for at least 10 years.
 

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I say put some liquid teflon on the bolt and put the bolt back in. On Mopar big blocks some of the exhaust manifold studs go into the water jackets, I've just used liquid teflon on those studs and they've never leaked.


Jordan
 

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I'm envisioning a crack that begins in the bolt hole and proceeds through to the material around it. Is this correct? If so, teflon thread sealer won't help the part of the crack outside the bolt hole. To seal the inside of the bolt hole with epoxy, chase it with the appropriate tap, hose it out with brake cleaner followed by clean dry compressed air, then put a glob of epoxy into the hole. Coat your bolt with a good heavy-weight mould-release compound (Johnson's Paste Wax if you don't have a specialty mould release product) and screw it into the hole until it bottoms and torque gently - this will spread the crack some and force material into it under pressure, and keep the threads open and accessible. Now the hard part is to know when to remove the bolt - too soon and it'll be messy, too late and you may not get it out. Depending on cure temp 8-12 hours is usually good, you want the material to be crosslinked enough to be rigid but not so fully cured that it won't yield. One criteria that usually works well for me is to wait until it just barely takes an impression from the edge of a thumbnail pressed hard. After it's fully cured you can again chase the threads with a tap, since the goal is really to fill the crack. Outside the bolt hole a surface glob is OK, but material inside the crack is much stronger.
 

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A buddy and I went to a performance shop (Mustang garage, actually), and saw a block on a stand. I asked them what they were putting on it and he said JB Weld. I didn't believe him at first, but he was serious. A 5.0 had threw a rod and it just got the edge of the block where the pan mated to it. A good little chunk was missing, but he said that JB Weld works good and he had used it before. Anyways, just thought I would mention it....
:D
 

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jb 4 minute weld is amazing, I wont hit the trail without it. I would weld it myself but I have expirence with that, some good, some bad...
 

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At the least stop drill the hole. If you are asking if mig welding cast can be done then yes and if your asking if you should mig weld the block the answer is no.
 
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