broken cylinder head studs
 

Well, I went for a drive and was hot rodding around and blew my head gasket. I read up on how to do it and took all the precautions. I really tried to be careful, and I tried all the methods that Ive been reading about on how not to break the head studs, but mine were very fragile and the lightest touch of the wrench, I broke 7...


I tried heat, soaking in kroil for a week, more heat. No luck.


I welded a washer to the ones that broke flush to the block, and welded a nut on top of that washer, and gave it a turn, only to find that the stud would break, or twist off even further down. I think my only option is to drill them out...not sure. I did drill one, but it didn't come out like I hoped. it's been down for 2 weeks now, I'm not too happy with myself.


https://i.ibb.co/KwsMMh2/broken.jpg

Re: broken cylinder head studs
 

In industry I would put the head back on and buy some drill bushings that fit the head bolt hole size. Then use an end mill through the drill bushing to mill a flat spot on the broken stud. Once that is done use a drill bit the size of the bushing to drill the center of the stud out. once you have a straight hole that's concentric to the stud bore try to extract it. If it won't come out, drill the bore out just below tap size and work the remains out with picks and a tap. There's a lot of technique involved but it can be done.

Might be simpler to find a good block and swap into it.

Re: broken cylinder head studs
 

Contact a few local machine shops and inquire about EDM Machining. It is possible to use an electric arc to burn the studs out and leave the threads. Not cheap. What is the condition of the rest of the engine?

Charlie Stephens

Re: broken cylinder head studs
 

This will be tedious but I'd keep at it. Try using your centre punch to start a drill as close as possible to the centre of the stud. Once you JUST start to get a cut, stop and check it for centre. If it is off, you can bring it back by using the centre punch again to put a gouge in the side of the impression you have made with the drill on the side you want the hole to go. Check again and repeat as neccessary. You will not be able to adjust the position of the hole once you have reached the full diameter of the drill. A little practice on a scrap of steel will pay off if you haven't done this before.
Makng sure you keep th edrill square to the top of the block in both directions, (an extra pair of eyes helps so ask someone for help), drill through to the bottom of the stud, then gradually increase the size of the drill till you are able to pick ut the remains of the thread as outlined above. If you still haven't got it right, all is not lost. Helicoils do a good job in this situation but don't drill too large.
Good luck and stay patient.

Re: broken cylinder head studs
 

I bought a Broken Stud Drill Out tool from Brattons several years ago. Can't count the number of broken studs I have drilled out over the years in my shop. Never damaged the threads. Brattons P/N 8235 $140.

Re: broken cylinder head studs
 

After drilling out the stud as close to the threads in the block without touching them


I use my acetylene cutting torch to carefully melt and blow the remainder of the old steel stud threads out of the block threads

The torch will quickly melt the steel stud threads without affecting the cast iron threads in the block

Re: broken cylinder head studs
 

Take block out to EDM machine shop easy for them I Know!

Re: broken cylinder head studs
 

Most all of the previous advice is good and will work IF, time is not a factor.

EDM is usually reserved for taking out broken tools too hard to drill or machine. It is slow and costly. I sold my portable machine because it was taking me away from the shop too much and running one is extremely BORING.

In your case a shop that is familiar with digging out broken studs such as yours, would machine them out in a milling machine with an end mill. Beside setup, no more than 2 minutes for each one. Less than $100.

Re: broken cylinder head studs
 

Re: broken cylinder head studs
 

It is a simple thing to weld a ball on the top of the broken stud. The heat from welding will help loosen it. Grab the ball with a pair of vise grips and unscrew it. On smaller bolts you can add ears like this picture.
https://i412.photobucket.com/albums/...pspyky4z41.jpg

Re: broken cylinder head studs
 

I think your at the Snyders tool and drilling stage. Take your time be patient you’ll
Get thru it.

Re: broken cylinder head studs
 

TIG weld is the trick. It may take several attempts on the most stubborn, but they will come out. I used an impact set low to turn the welded nut.

Re: broken cylinder head studs
 

This is all a GOOD reason not to be too quick to remove the head unless it is absolutely necessary .