I am startin my project BBB with the breakdown of 2 455'S. One is 1974 out of 74 RIV. The other is 1970 of unknown origin. I plan on using the 1970 for the heads. Well, in the careful removal of the exhaust manifolds there is 2 bolts broken off. They were badly rusted. It doesn't look like removal is gonna happen without drilling. My question is what is my best path here? Is helicoils the way to go??
If you're going to have the heads machined or rebuilt, then jsut have the machine shop install the helicoils. It is worth the pain and suffering to pay them to do it.:TU:
You can do it yourself but keep in mind that if thr coil is off just a hair, the manifolds or headers will never fit right. The machine shop will have a jig to do the job correctly.
Read this link, it works! My Dad taught me this years ago, but Mark explains it so well... http://www.madelectrical.com/workshop/broken-bolts.shtml
Thanks for the replies. I think I will leave it for the machine shop. I would really hate to screw up those heads:beer
First thing I'd probably do - center a nut over the broken bolt/stud and weld the nut to it(fill up the hole). You should be able to work the broken bolt/stud back and forth, to loosen up the rust on the threads!!:Smarty: Hey...if the nut comes off - no biggie, you had to have it drilled out anyways!!:TU:
I used the "left hand drill bit" method and it worked very well for me. I purchased my drill bit set from Chris Austad 507-373-4545 at a much lower cost than snap on. Broken bolts and studs come out with little effort using this method. Jan Garwig
left-hand drill method Yes, it does work very well. Much better than having heli-coils installed. Those threads are not as reliable, obviously. Give it a shot, I think it will amaze you how easy it will come out!:shock: At least read the article.
Some tricks I have used over the years. 1) Spiral easy outs are stronger but tend to swell the "Dutchman" (sorry if I hurt anyones feeliings), if using a spiral easyout don't get too close to the threads where it just wedges the threads together. 2) If the bolt is broken off flush, take some extra time and work the broken piece over with a drift punch and ball pien hammer. Tap on the center of the broken bolt moderately, don't swell the piece out. Build a puddle of penetrating oil over the area and let it soak in and then work the area again. This can never hurt the piece, only help. I have had the best luck with "AeroKroil" penetrant. 3) I learned this trick in the service working on aircraft; Using easy outs, Use above procedure then drill your piece with the proper size drill going a little bit at a time. Do not drill all the way through. If you do punch through you can jam a tiny wad of tin foil in the bottom of the hole. Have everything ready (easyout, tap handle, small ball pien). Crush some ice or dry ice if available, you won't need much. Using a plumbers turbo torch, heat the area (just heat, not weld!!) by concentrating the heat on the broken bolt and let the heat work its way outwards through the threads (a "slight" breeze will help with the fumes from the burning penetrant) heat the area good and hot slowly so that the heat is not just on the surface but deep. using tweezers place a sliver of ice in the hole and let it "cook off" keep putting ice in until it stops cooking and immediately put the easy out in and apply left torque and bang lightly on the tap handle with the hammer. This works most of the time due to the bolt contracting faster than the surrounding metal. Having everything ready is the key to success, having a friend help you is a good idea also. I hope this works for you. Lou
Last time i broke bolts (which was, coincidently, also in the heads of my 455), I tried everything. I finally resorted to welding a nut to the broken bolt, and all that accomplish was shearing the bolt off closer to the head. If you're really, really good you can drill out a bolt without having to helicoil it. You'll know it worked when you can peel the threads out of the hole like a giant slinky. It doesn't normally work on rustwelded bolts, though.
Thanks for all the replies. This board rocks!:beer . I will be workin on the engines this Sunday. Still not sure what I will do about the broken bolts yet. I would like to think I could have both motors stipped down sunday.
I like the oxy-acetalene method. Heat it up red hot and have a set of vise grips handy. Work it back and forth till it starts moving and spin it out. Done this on a few sets of heads. Only had one break off completely. I drilled it out and cleaned the threads with a tap.
