That’s exactly correct.

That’s where I broke my bolt.

It may be reparable with a 1/4 x 26 BSF helicoil

That sounds encouraging although It might be tricky to get it in far enough to leave room for the dowel.

Gordo

This is a job for ed at E&V Engineering. in Michigan or
Jake and Rob Hall at Halls Custom Vintage, or HCV in Nort Carolina
Frank Deihl at Classic Cycle works in South Carolina

I found a few shops who I’m talking to.

I’ll keep you posted.

That’s why I’m going to take it to a shop. I’ll just screw it up.

Get some of these next time you need to drill out a broken stud/bolt, see how the flutes are all LH spiral except for the single RH one added as a comparison. So you drill in reverse you do not force the stud/bolt in tighter but actually have a chance to loosen it enough so it turn with pliers.

Or you can find a shop with an EDM machine and have the bolt remains electro-discharge blasted out without damaging the aluminum. I had this done to and Alpha V6 block to remove the remains of the head studs that were seized after I machined off the exposed portion.

I’m going to the movies with my wife to see Ford vs Ferrari. I am also building a 1968 Ford GT40 and it’s in my garage next to my motorcycle. That will take my mind off of me being so stupid.

Thanks Adam, you are 100% correct. This isn’t a big deal, just a set back. [/quote]
How about a pic of that GT40. Love seeing older race cars.

It’s a work in progress.

Nice. Bet that's a tough build.

If I understand correctly, the screw is out and now you have an oversized hole there.

I'm a bit out on a limb here, because I've only had a few cursory acquaintances with B44s, but I think that part is like an A65. If so,

The screw is in the inner timing cover, not the crankcase. So absolute worst case is a timing cover (ie, not the whole engine!).

You do need something there; without it, the spring will eat into the timing cover. I've seen this on A65s where the screw was left out.

That screw never has to be removed to disassemble the engine, so you could have a post welded in place there.

If the threads are damaged I think the easiest solution is to drill and tap for an insert then make an oversize tubular stepped dowel that will press in over the insert and remove the dowel from the timing cover. The engine does not care which side is doweled.
Mark, as you sure it does not have to be removed to take off the timing cover? It appears to have a hex integral with the bolt.

Mark: The bolt in question goes through the inner cover into the case. If you look at the photo I posted earlier I show the bolt screwed into the case, The inner cover, not shown, fills in the gap. As well the bolt is important for holding the inner cover on as that is the furthest aft point for attaching the inner cover. Some outer cover screws are aft of that but do not hold the inner cover on.

Gordo

You’re 100% accurate Gordo

I found a shop that will helicoil it for me. That will fix it.

Gordo has it right. Did it break off at the hex on the outboard side of the inner cover? have you taken the inner timing cover off like DM asked? Not enough of the bolt sticking out to heat it and grab it with real vise grip pliers? if its rung off flush with the rs case I/2 that's a harder fix for sure. might have to Dremel into the mount hole to remove the bolt and have the boss rewelded, drilled then install a thread insert.

I do a lot of TIG welding and often remove stuck broken bolts. With the focused arc you heat a bolt to 2K f instantly which when it chills usually collapses the rust matrix allowing the bolt to just spin out. I sharpen a scrap socket head and weld it right to the end of the broke bolt.

All of the screws in my access cover were ruined and they all came out using this process. I welded little handles on the 8-32? screws and they came right out.

Untitled by barnstormerbikes, on Flickr

Hmmm, doing that on old sand cast alley cases normally results in them being banana shaped when you are finished.
Those screws can be drilled out and either helicoiled or tapped for 5mm ones. (done this many times.)
The last thing i ever want done on cases is any welding, i'll do whatever i can to avoid it, the bloody things always distort.
Just my 2c of course.

Take another look. I weld extensions on broken bolts and the case hardly gets warm, all done in 20 min. I trust your advice is based on your experience so you have my confidence. Proceed with conviction.

Fair enough.

The standard screws are BA.

aluminum is an excellent conductor of heat. thats why pistons are made of it. I have blown broken studs out aluminum with a cutting torch. not for the feint of heart, but it works. thats not a likely solution in this case because the bolt being broken off deeper inside. I have also welded a nut on to a broken stud.. that is my #1 way to deal with them, a nut set over the stud, then MIG it, starting on the broken stud and filling out to the nut

This may help?When bolt is broken off deep inside hole.Run tap to clean existing thread. -Spray with brake cleaner or something to remove grease,swarf etc. -Find a bolt(grade 8 or better) the same thread and just a little longer. Drill hole through centre of bolt just a little bigger than the gasless Mig wire -Screw bolt in- insert Mig wire-Weld- Hopefully unscrew all out. Works for me!