I have a flathead, and I have a problem. My problem is that the S.O.B. that sold me my flathead did not tell me that rats made their home inside the valley. The good news is that I know for a fact that the block is not cracked. This is my only solace. Removing parts from the engine, however, is a different matter. I tried to remove some head studs, and a few of them broke off in the block. At first, I panicked, but then I realized I have the skills to drill out most of the stud. Because the stud is a softer metal than the surrounding block, I can drill out everything except for the metal clinging to the tread. My only problem is that I do not have a tap even close to the original tap. Does anyone know where I can acquire one?
There's been some discussion on the pros & cons of running taps through the block threads in the first place - much less, trying to remove rusted in pieces. You can probably weld a nut to the stud & back it out. ...or take it to a machine shop.
I would talk with andy on here and he welds a fat washer onto the stud with a stick welder I would guess he uses 7018 rod then welds a nut to that and they come right out he says.
The studs broke off after I welded the nut to the stud. The torque from me trying to turn the stud broke the stud off. Poor quality metal I suppose. I understand that I might have to run a helicoil or something close to it, but the broken stud piece isn't rusted in the hole. It is solid alloy. It is just stuck to the threads. Any ideas?
I've always heard to heat the area up & then melt the candle onto it - otherwise, when the hot wax hits the cool block, it will just coagulate & not wick down the threads... ...never done it though, so YMMV.
I have done this method with a MIG vs. stick and it has worked everytime. I use a think shock absorber washer & place it over the broken stud. Generally, the break flush with the deck surface. Getting a good weld with enough heat is the trick. I make a nice bud of weld & put vice grips to it while it still hot. IMHO, the heat helps to break free the bond of rust as well. Good luck. I would also agree that if you are not comfortable with this procedure, have a professional do it rather than mess up an otherwise good block.
I fogot to ad. I also heat the area with a "B" tank- (plumbing set-up) and spray areo-kroil on it. The heat helps to wick the stuff down to the threads. Do this a few days, a couple times a day before. It certainly is a PITA, but I'd rather be safe than sorry when doing a repair like this.
The studs are not softer than the block. They are heat treated steel and the block is cast iron. The welding the washer deal works but there is a catch. The heat treated steel becomes brittle at the weldand will shear off. The first step is to get the stud red hot to anneal it. Then it can be welded and removed. If you have them drilled, just heat them up and try an easyout. Weld them if you have enough to weld. I like to drive sharpened torx bits into drilled studs. They will cut 6 flutes and be like splined . The bits will unscrew them without adding side presure.
Andy: I like this. When you say sharpened, do you sharpen them? What size Torx has worked the best in your opinion? Thanks for the information.
It is a judgement call. Sellect a size almost to the minor dia of the threads. Drill a hole that will let maybe 1/2 or less of the flanks of the bit to cut into the studs. I guess sharpening is the wrong term. I grind the end flat and grind enough off so the edges of the bit are sharp. As made they are a little rounded off. Just shorten them up and get good edges on the ends. I drive them in with a hammer. They will cut 6 splines as they go.
Once you finally have the broken stud - bottom of bolt - out of the hole; PLEASE, PLEASE, PLEASE - DON'T use a regular TAP to clean the threads! Regular taps will remove more material and cause the fastener to fit "sloppy." A proper "thread chaser tap" is the ONLY way to clean the threads. The inexpensive ones - even the Snap-On ones - don't have enough length to get to the bottom of the holes. ARP makes very high quality "thread chasers." (look like regular taps, but don't cut into the existing threads; and are longer) http://www.arp-bolts.com/Catalog/Catalog.html PAGE 87 If the threads are damaged; one alternate to "helicoil" repair are these ... http://www.timesert.com/index.html
You need to have the stud almost flush with the top of the block when you weld the washer to the stud. The studs are 7/16 14 thread. Use a washer that has a hole just a little smaller than the stud. I use a mig and try to be sure to get the end of the stud good and red hot. Set your welder up good and hot, pour the heat it. Start welding in the center of the stud and work your way around to the washer and weld it on good. Even build it up some above the surface of the washer. The heat you put into the stud helps to break the rust bond to the head. Then you weld a good size nut to the top of the welded washer. Let it cool. Throw some penetrating oil on the whole mess. Don't waste your time with WD40. Get some PB Blaster or similar. Then get a good box end or six point socket on the nut. Start to pull on the wrench. Once it starts to move, work it back and forth adding more oil. It will come out. If you twist off the washer/nut ***embly, just weld on another setup. The additional heat will help it more. Good Luck. I would never try to drill one out. If you break off an "easy out" you will find that the name "easy out" is wrong.
Do not use a torx bit as listed above. I have tried it twice since that thread was posted and all it did was break my bits. Try the welded washer but do not try the torx bit. It doesn't work.
Say someone to remain unmentioned (myself) screwed up and drilled out about 4 studs and tried to collapse the threads into the holes. Now a stud fits sloppy in the hole. If I can torque the stud to specs and am planning on running a fairly stock flattie, do they really need to be helicoiled?
You can try it & see. I'd heli-coil them. Use a jig to ensure you're drilling/tapping square to the surface - nothing worse than a crooked stud!
I'd never try anything like a torx - as chances are that it would just break off and then I'd have a real mess (like a broken "easy out"). If the original stud was so rusted that it broke off -- then chances are that you're going to break off the easy out or the torx the same way. The welded nut idea seems to be the best (from all I've heard). If I have a good block that I'm planning to build - I'd take it to the machine shop unless I've tested my work on a **** block and know that I have it figured out.
Here's how I do it, it makes a little mess but easily cleaned up. Heat the end of the bolt/stud with a cutting torch, when it's hot enough press the oxy lever. Sparks and plasma shoot out of the hole, it's spectacular but don't panic, leave the torch in the hole for a few seconds after the **** has gone and move the flame around. Take a look down the hole, ohhh aahhh you can even see the threads, clean with a chaser and you're done. BTW you can't damage the block, it's cast iron and can't be flame cut. Just wear some safety gear, what goes up must come down.
Thanks Ernie -- I really have to respect that answer. I will try to get the last bolt out when I get a MIG welder and then bring the block to the machine shop to see if its worth doing anything with. I'll probably helicoil right away, as its easier to do at this point rather than later.
My dad got a smal block of aluminum & drilled a hole in the drill press so it was square. At the other end, he slotted it. Put the slot on an adjacent stud, set the square hole (haha!) over your damaged hole & drill/tap confident you're going into the deck reasonably square. Most of the holes go through, but I think a couple of them don't - check & see before you drill all the way through!
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