wheelman Posted January 11, 2004 Share Posted January 11, 2004 Well I pulled the exhaust manifolds off my iron head LT1 and found a stripped bolt hole. There are still threads in it but they are in bad shape and will not hold torque. What is the best way to repair this? Here are the ideas that pop inot my head. 1. Drill and tap to the next larger bolt size. 2. Drill and tap, then install a heli-coil kit for original size. 3. Have a machine shop weld up the hole and re-drill and tap. I'm not sure a heli-coil will hold the torque, what do you guys think? I do plan on having a value job done so maybe I should just have the hole repaired at that time. Or should I just trash the iron heads and replace them with aluminum. I would do this but I really don't want to spend the extra $$$. Yeah I'm extremely cheap!! Ken W. Quote Link to comment Share on other sites More sharing options...
dune333racing Posted January 11, 2004 Share Posted January 11, 2004 thry going to your local parts house and buying a helicoil kit to repair the threads in the bolt hole. Quote Link to comment Share on other sites More sharing options...
Guest Bob L Posted January 11, 2004 Share Posted January 11, 2004 I'd avoid a welded repair on an iron head, let alone a thread. A threaded hole is, by definition, a stress riser. Because of the high carbon content, iron has a nasty habit of breaking right next to the weld. High nickel filler rod + careful pre-heating helps, but it's still likely to crack. I've welded iron on occasion and my recommendation to you is to not weld it in this situation. Helicoils are reliable. Just make sure you use the exactly the recommended size drill and tap and the Heli-coil installation mandrel and prewinder. I wouldn't hesistate to use one. Bob Quote Link to comment Share on other sites More sharing options...
EvilRufusKay Posted January 12, 2004 Share Posted January 12, 2004 Although I have never installed a helicoil, I have had many (horrible) expieriences removing bolts that have been threaded into them. They always seem to work there way out do to corrosion adhearing to the bolt. IMO I would drill and tap to the next bigger size. You might first try to run the current size tap in there...you may be able to salvage the original threads. Rufus Quote Link to comment Share on other sites More sharing options...
wheelman Posted January 13, 2004 Author Share Posted January 13, 2004 Rufus, I took a closer look at the threads and I may be able to salvage them. I must remember to try the simple stuff first, besides it gives me good excuse to get a good tap and die set. Ken W. Quote Link to comment Share on other sites More sharing options...
EvilRufusKay Posted January 13, 2004 Share Posted January 13, 2004 Very Cool...Glad to hear it...let us know how she works out Quote Link to comment Share on other sites More sharing options...
denny411 Posted January 14, 2004 Share Posted January 14, 2004 If you use green loctite on the helicoil, and anti sieze on the new bolt threads you shouldn`t have any problems with using a helicoil to make the repair. Quote Link to comment Share on other sites More sharing options...
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