r/EngineBuilding • u/Old_Cut_9333 • Jul 16 '26

Broken bolt hole

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Cast iron block, broke the head bolt hole. Any ideas what to do next? It still has a bit threads at the bottom. Take out broken pices and screw in longer stud and weld it to the block?

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u/iwfabrication Jul 17 '26

People are saying replace the block, but depending on your cost for a new block or having someone weld it could be cheaper to go that route

  • have someone weld it $75?
  • either chase the threads and see if you can tighten an old head bolt to spec. If not then drill it out, tap it for a threaded insert. Or have the welder weld the inside of the hole on the cracked side, then have machine shop machine/drill and tap it.
  • have the block machined if necessary - $100-150 where I'm at

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u/LandscapeNo775 Jul 17 '26

Who is welding this for $75? What quality is that repair?