Uberoo Posted August 10, 2010 Author Share Posted August 10, 2010 allready tried the reverse bit.couldn't get it centered.a 7/16 drill bit passes through the dowel and is centered.I thought about just drilling the little bit of aluminum in the bore until I got to the broken bit then the centered 7/16 bit could start to make a center hole.then hopefully I can use the reverse bit and pull out the bolt... Quote Link to comment Share on other sites More sharing options...
GeneralDisorder Posted August 10, 2010 Share Posted August 10, 2010 How much thread do you have left on top of the broken bolt section? GD Quote Link to comment Share on other sites More sharing options...
Uberoo Posted August 10, 2010 Author Share Posted August 10, 2010 (edited) it broke off at the very end of the treaded section so I have no threads to play with. are really long helicoils available?I went down to parts store earlier and the helicoil kits they had,had a bunch of 3/4" long helicoils.I don't know if stacking multiple helicoils would work. Edited August 10, 2010 by Uberoo Quote Link to comment Share on other sites More sharing options...
GeneralDisorder Posted August 10, 2010 Share Posted August 10, 2010 it broke off at the very end of the treaded section so I have no threads to play with. With it that far out and accessible you need to center punch it and start with a small bit. It is VERY VERY critical that you center punch it right. If you don't know how to correct an off center punch you need to read up on it. are really long helicoils available?I went down to parts store earlier and the helicoil kits they had,had a bunch of 3/4" long helicoils.I don't know if stacking multiple helicoils would work. Yes you can stack them. They also expand as they are threaded into place by around 25 to 50% GD Quote Link to comment Share on other sites More sharing options...
Fuzpile Posted August 10, 2010 Share Posted August 10, 2010 When I was doing this there was a kit which had helic, tap and driver except i really didn't like that the length wasn't the same. The problems of two and possiblity one would shift and lock the bolt is frightening. there must be a special procedure about that. The centering is so important becase if a tap or bolt is run in a hole and some part of the old bolt is there, it breaks loose and wedges. then stuff gets broken. Quote Link to comment Share on other sites More sharing options...
GeneralDisorder Posted August 10, 2010 Share Posted August 10, 2010 They can't really shift - they are held in alignment by the heli-coil tap threads. In other words they can only rotate but never in such a way as to jam up the threads. It's perfectly safe to use them in a stacked situation. That is most likely how a shop would repair it. The centering and aligning of the drill is the most important procedure and with something like an EJ head bolt with threads that are several inches long I would probably do it with the engine out of the car and using a mag-base drill press, etc to insure complete alignment with the block mating surface. This is a very critical fastener and a tough job to get right even for us that know what we are doing. I would take it to a machine shop if I were you. GD Quote Link to comment Share on other sites More sharing options...
Uberoo Posted August 10, 2010 Author Share Posted August 10, 2010 what is the thread for the stock ones?Should I bring it to a machine shop and tell them to fix it with some supplied helicoils or have them fix it with whatever they got? Quote Link to comment Share on other sites More sharing options...
GeneralDisorder Posted August 10, 2010 Share Posted August 10, 2010 A machine shop will likely have every size on hand. If they don't then they will order it into their shop supply - they usually have a standard fee for broken bolt removal and thread repair. GD Quote Link to comment Share on other sites More sharing options...
Uberoo Posted August 10, 2010 Author Share Posted August 10, 2010 still need to know what size it is. Quote Link to comment Share on other sites More sharing options...
Gloyale Posted August 10, 2010 Share Posted August 10, 2010 Man I would find a different block if I was you. This (rethreading an already rethreaded hole) will be a pain in the rump roast.....cost money......and in the end you may still have a shot block. Plus aren't the heads warped too? EA blocks are EASY to come by......find another. Quote Link to comment Share on other sites More sharing options...
Uberoo Posted August 10, 2010 Author Share Posted August 10, 2010 EJ22 that why its in new generation. Quote Link to comment Share on other sites More sharing options...
GeneralDisorder Posted August 10, 2010 Share Posted August 10, 2010 I'll have to measure one for the size. I'll do that later today since I'm reassembling a 22 that burnt a valve. Have to pickup the heads and gaskets still this afternoon. $185 for resurface/valve grind (both heads), and repair of an exhaust valve with a 1/4" hole burnt in it on the #4 cylinder. Unusual failure GD Quote Link to comment Share on other sites More sharing options...
Uberoo Posted August 10, 2010 Author Share Posted August 10, 2010 Does anyone know what the thread size is?I took one of the old bolts into the hardware store to find a helicoil and 7/16-20 AND M12-1.50 BOTH thread down the entire length.Only difference is the M12-1.50 is just a little loose.the metric nut will thread all the way down then slide down the un-threaded section.the 7/16-20 threads down all the way and then STOPS when the threads end.I would like to think that because its a subaru it would be metric thread,but then the metric nut was a bit loose.So anyone know what it is? Quote Link to comment Share on other sites More sharing options...
GeneralDisorder Posted August 10, 2010 Share Posted August 10, 2010 Taking your measurements into account, and the fact that EA82's are 11mm x 1.25..... My guess is that the EJ bolts are the same. In other words it's a special order Heli-Coil - no one stocks them. GD Quote Link to comment Share on other sites More sharing options...
Uberoo Posted August 10, 2010 Author Share Posted August 10, 2010 so then it probably would be unwise to helicoil it to 7/16 20?Even though the 7/16-20 is VERY close to M11-1.25 on a metric drill and tap chart I found that to tap a M11-1.25 you drill a 9.75 mm hole.7/16-20 is a 9.9 mm hole. .3838" vs .3897". like I said I can thread the 7/16-20 down the entire length of the stock bolts. Quote Link to comment Share on other sites More sharing options...
Fuzpile Posted August 10, 2010 Share Posted August 10, 2010 UB, Gen D is getting back to you. He knows all about these. It could be the hdwe store grade is homeowner grade and not as precise. Also since he mentioned a mag-drill and it's alum block it's because he knows they have various steel plates with differnt holes that will line up to block bolt holes. What a person Could do is use a smallish drill press but it may flex. The unthreaded area will accept a bushing. Inside the bush will accept a straight punch which are of every dia. That is what pokes the start of the next drill which might excactly fit that bushing too. Then the last size is guided by above plate/etc and that true pilot hole. Quote Link to comment Share on other sites More sharing options...
GeneralDisorder Posted August 10, 2010 Share Posted August 10, 2010 so then it probably would be unwise to helicoil it to 7/16 20?Even though the 7/16-20 is VERY close to M11-1.25 on a metric drill and tap chart I found that to tap a M11-1.25 you drill a 9.75 mm hole.7/16-20 is a 9.9 mm hole. .3838" vs .3897". Drill/tap charts are very misleading. Point in fact most are incomplete at best because there are about half a dozen drill sizes for any given tap depending on thread engagement percentage - which depends on factors like the depth of the threads, how loose/tight you want the fit, the type of materials and temperature expansion rates being used, and how much torque the fastening system must withstand. Changing a thread or mix/matching thread sizes and pitches on a fastener with a critical functions such as a head bolt IS WAY ABOVE YOUR PAY GRADE. . Don't do it. Likely it will be an epic fail and you will be this guy -> like I said I can thread the 7/16-20 down the entire length of the stock bolts. I understand - but just because it threads on doesn't make it right nor capable of holding 86 Ft/lbs of torque. We are talking about aluminium threads and a steel bolt. Improper fit might strip it out on the final torque, or it might hold through a dozen or a couple hundred heat/cool cycles before failure. Without careful examination on an engineering level you are asking for a very probable failure here. It will not be pretty if that bolts pulls out. Repair it right or just find another short block because if you do it wrong that's what will be happening anyway - just with more swearing and down-time. GD Quote Link to comment Share on other sites More sharing options...
GeneralDisorder Posted August 10, 2010 Share Posted August 10, 2010 UB, Gen D is getting back to you. He knows all about these. It could be the hdwe store grade is homeowner grade and not as precise. Also since he mentioned a mag-drill and it's alum block it's because he knows they have various steel plates with differnt holes that will line up to block bolt holes. Exactly - you would use a steel plate and bolt it to the head with all-thread. . The mag base drill press would then be able to drill the hole perfectly perpendicular to the block surface. I suspect that he does not have access to that kind of tooling though. GD Quote Link to comment Share on other sites More sharing options...
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