jono Posted March 12, 2016 Share Posted March 12, 2016 (edited) I'm curious as to others preference for thread repairs to our old girls alloy components. I uses a brand Recoil which is similar concept to Helicoil brand. In addition to the preferences, can you add a brief description as to how you carry the repair out please ? the coil repair method involves drilling out the damaged thread with larger diameter drill bit, using supplied thread tap to rethread hole, then wind in a coil spring like looking thread insert that has an internal and external thread. They are usually only able to be threaded in and not backwards and out if you stuff something up. Over the years have seen others quote a repair that is a more solid (hardened? insert that I can only imagine requires a much larger diameter drilled out hole, larger tap to suit and this is where hole centre accuracy might drift off in my mind. I did a non Sube alloy recoil repair the other day and was not happy with the thread the supplied tap cut into the alloy, looked more torn than cut ,but is holding at the moment pics would be good if can do Edited March 12, 2016 by jono Quote Link to comment Share on other sites More sharing options...
skishop69 Posted March 13, 2016 Share Posted March 13, 2016 Helicoil is the cheapest and easiest and will hold fine when done properly. Always use Permatex green sleeve locker on the coil when inserting it the let it cure overnight before putting it into service. The sleeve locker will permanently bind the coil to the part and stop the coil from unraveling when the bolt is torqued down. The other repair, which is more expensive, but far superior is a Threadsert. Yes, the hole is slightly bigger, but it will never fail. We use these to rethread the Cadillac Northstar engines when doing head jobs. Nothing better. 1 Quote Link to comment Share on other sites More sharing options...
Roger87ea82t Posted March 13, 2016 Share Posted March 13, 2016 When cutting the threads with a tap in aluminium alloy always use a light thread cutting oil or WD40 works also. After you cut 3 or 4 revolutions remove the tap and clean out the chips, then more cutting oil and 2 or 3 revolutions and remove and clean out chips again. Repeat this process until you finish the hole, if you try to do it in one pass there is a chance the aluminium chips will gaul the threads and they will not look clean, When cutting threads in aluminium you need to go slow and be careful, if you meet any resistance remove tap and clean chips out and use plenty of fluid. Roger Quote Link to comment Share on other sites More sharing options...
idosubaru Posted March 13, 2016 Share Posted March 13, 2016 (edited) Drill tap insert done. I've never seen a need to overthink such a simple nearly 100% repeatable solution. I use Helicoils just because of availability that's what was easy. I'd gladly use threadsert too if it presented itself as an option. Edited March 13, 2016 by grossgary 1 Quote Link to comment Share on other sites More sharing options...
DaveT Posted March 13, 2016 Share Posted March 13, 2016 I've used Helicoils. Have not had any trouble. The fancier threadserts sound good too. Quote Link to comment Share on other sites More sharing options...
moosens Posted March 13, 2016 Share Posted March 13, 2016 There to stay - heli coil Need to remove in the future - Timesert , or those inserts mentioned. Quote Link to comment Share on other sites More sharing options...
jono Posted March 13, 2016 Author Share Posted March 13, 2016 OK, thanks for the replies guys. Roger, if you had not used a few technical terms I may not have believed you ! When I was being instructed on thread cutting in school, all we had was mild steel - alloy was only in the theory boooks and yet to appear in our GM and Ford vehicles and the teacher drove a mini panel van as seen in the Heartbeat TV series I actually developed the theory if cutting threads in alloy don't turn back as taught with mild steel and got a better result. I will give the next job some CRC556 or WD40 under sufferance and see how I go - job is waiting for me now, up on stands, an exhaust stud on an EA81 head. I don't have any loctite green stuff and wonder if any loctite threadlocker can withstand exhaust temps ? I have done recoil/ helicoils for years and mostly success and without any thread locker goo at all, but is good to know others have similar success - just that once in a while someone comes up with the hardened larger inserts were superior. They are not as readily available as the coil repair brands.. See if I can remember timesert and threadsert names for future trials Quote Link to comment Share on other sites More sharing options...
skishop69 Posted March 14, 2016 Share Posted March 14, 2016 Yes, the green sleeve locker Loctite will resist exhaust temps. It's good to 700 or 800 degrees. Only way to get it out is with a torch. I don't back the tap up more than a turn when cutting aluminum. I've found it tends to wallow out the hole. I do, however, blow compressed air around the tap to clean the chips out and use plenty of lube. Timeserts are not truly removable. Because of the installation method, the whole becomes expanded when installed. More so when installed in aluminum making it near impossible to get a tight fit if you try to install another. They are extremely hard and I've never seen or heard of one stripping out. Seen plenty of bolts strip , but not the Timesert. Quote Link to comment Share on other sites More sharing options...
moosens Posted March 14, 2016 Share Posted March 14, 2016 Clarifying my post. Timesert if you think you'll need to remove that bolt in the future. That's right , the insert - Timesert - does stay there. I've had great experiences with them , only my wallet was crying. Around exhaust that's what I've used. Cheers! Quote Link to comment Share on other sites More sharing options...
jono Posted March 14, 2016 Author Share Posted March 14, 2016 I'm gonna bet the green loctite is something not available in Australia so not gonna search too hard for it. Anyway, the Recoil (an Oz /brand? address and says product of Australia with Sth Korean tap) has been done. This time I ran the tap back out and blew it clean each of the three times - used CRC556 to blow the chips into the garden , so, okay, may go back to the turn tap back enough to cut the crud, and sally forth on the next job. Stud is in, new gasket and silicon in place. If only the exhaust place that hit the previous owner up for nearly $500 ten years ago for a new catted Y pipe could have repaired the threads on the other side. They cut and welded the new Y pipe to take advantage of the diagonal stud holes instead This engine is only thought to be in for a short time until an EA82 goes in, either one I have built and sits in another Brumby or I have an mpfi short motor screaming out for heads and new timing belt kit and HVLA. Or maybe even the EA82T as originally intended Quote Link to comment Share on other sites More sharing options...
skishop69 Posted March 14, 2016 Share Posted March 14, 2016 Clarifying my post. Timesert if you think you'll need to remove that bolt in the future. That's right , the insert - Timesert - does stay there. I've had great experiences with them , only my wallet was crying. Around exhaust that's what I've used. Cheers! Yeah, they're not cheap for sure. I only use them at work or if I really booger up something at home like a head bolt. Quote Link to comment Share on other sites More sharing options...
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