Update on Removing Broken Head Bolt

[19Fordy]

Here's the message I just got about the broken head bolt along with a photo. My buddy Joe says: "Tell the Fordbarn folks I really appreciate their input. They have helped me a lot."

"The attached pictures are of the block looking from the front to the back.
I finally got the head off by rotating and prying up the head. BUT the bolt still remained stuck in the head and pulled out from the block. It took some of the threads and a small amount of the casting from the block.It may be repairable with some kind of epoxy filler and re-tap the hole. Not sure yet what to do."

The remaining broken shank of the bolt came out and also pulled the first couple of threads in the block out and chipped the block as shown. The broken stud is still frozen in the head and will not budge. Now that the head is off ,the broken off bolt in the head is being drilled out a little at a time until there is enough clearance for a new headbolt to fit. It is as if the stud is welded in place in the head. Heating and soaking with transmission fluid and acetone mixture as well as PB Blaster did not work. There are no cracks in the block and the cylinder walls.

QUESTION 1 : Do you think JB Weld or DEVCON will work for filling in the chipped block. The depth of the threads in the block are 7/16 in and go into the water jacket.
QUESTION 2: Do you think a Timesert or a Keensert should be used rather than rely on the threads that are remaining? The heads are torqued to 55 lbs.
QUESTION 3: Would it be a good idea to first use a socket and a head bolt and torque the headbolt to specs. (without the head installed) to see if the remaining threads are strong enough?

Once again, thanks for your advice and knowledge. JIM

[flatjack9]

The block needs to go to a machinist. My machinist makes his own thread inserts and installs them. They come out perfect. I would not use a torque of more than 45 lb. ft.

[Ronnieroadster]

That's a really bad area to try and seal correctly. If I was trying to attempt a repair like this on an assembled engine I would first repair the damaged thread with an insert that has a tapered shape on the bottom with a flat top surface diameter to help increase the surface area into the damaged space. I'm not sure such a repair insert is available commercially if it was me I would just machine my own. This would provide all of the thread strength. After that I would use an epoxy to fill the remaining area that's damaged. Taking care to level the epoxy so the head gasket seals correctly. Doing it this way would be a gamble but if done correctly it should hold.

[bbrocksr]

Originally Posted by Ronnieroadster

That's a really bad area to try and seal correctly. If I was trying to attempt a repair like this on an assembled engine I would first repair the damaged thread with an insert that has a tapered shape on the bottom with a flat top surface diameter to help increase the surface area into the damaged space. I'm not sure such a repair insert is available commercially if it was me I would just machine my own. This would provide all of the thread strength. After that I would use an epoxy to fill the remaining area that's damaged. Taking care to level the epoxy so the head gasket seals correctly. Doing it this way would be a gamble but if done correctly it should hold.

Good plan, and then i would use a stud and nut with loctite or sealer instead of a bolt making sure to engage all the threads.
Bill

[alanwoodieman]

Belzona 1212 epoxy for cast iron block repair. thread insert for the repair to threads, I would also use a stud and nut to put back together. is the cracked off piece look new or old?

[KiWinUS]

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Jack & Ronnie know what is best from experience. Follow their advice & you will be fine.

[JSeery]

As suggested, even if you use bolts in the other locations, I would use a stud in this one.

[flatjack9]

No disrespect, but this is not a backyard repair.

[Pete]

First, you are going to have to disassemble the engine for a lasting repair.
I would do similar to what Ronnieroadster described.
I would offset drill and bore a hole, leaving as much original metal in the fire ring area as possible.
Try NOT to disturb this area.
Tap the finished hole for a 3/8 taper pipe thread.
Make a steel plug with a 3/8 taper pipe thread on the outside. NO CENTER HOLE.
Leave enough extra material on the top of the plug to grab it with a small pipe wrench or vise grips. Goop the threads with high temp Loctite and install the plug.
Surface the plug close to the deck with an end mill. Do not touch the deck.
Use a large flat file and clean the plug even with the deck.
Mount a clean head on the deck and clamp it with 3 or 4 bolts. Dial in the bad hole and clamp the mill table. Remove the head. Center drill and then drill and tap the hole for a 7/16-14 thread. Drill through to water. You will use high temp RTV for sealing the stud thread when installing. By using all studs on reassembly, you will greatly decrease the chances of this problem reoccurring.
BEFORE GOING ANY FURTHER, you need to test the repair.
A simple tool has been described several times on this forum for doing this.
Now have the deck surfaced just enough to clean it. Clean the other deck as a precaution as long as the block is in the machine.
Hit the cylinder bore with a RIGID hone to clean any bulge that might have come from installing the plug.
This repair will hold at least 90 ft. lb. of torque in testing as long as the the block wasn't totally rotted out under the deck..
This repair has been used successfully in land speed racing and sprint car engines since the 50's so we know it works.

For a cosmetic repair of the corner of the block, (outside the plug) any Bondo or epoxy putty can be applied and filed off to appear as if nothing happened.

[Tim Ayers]

Originally Posted by alanwoodieman

Belzona 1212 epoxy for cast iron block repair. thread insert for the repair to threads, I would also use a stud and nut to put back together. is the cracked off piece look new or old?

Belzona 1212 vs. their 1111 epoxy is a better choice here since the 1212 is designed to be used when there could still be a presence of oil contamination or you are unable to get the area surgically clean.

[19Fordy]

Thank you all very much for all the knowledge, advice and insight you provided. This started out as a project to replace a blown head gasket. Will let you know how it finally turns out when finished. JIM

[19Fordy]

8/12/21 UPDATE The JB weld folks were called and they recommended the epoxy they would use for repairing and re-tapping the damaged threaded block bolt hole. The head was milled .007 in. and installed using copper spray sealant and new Grade 8 head bolts and hardened washers. Head was torqued to 50 ft. lbs. in 3 heat cycles. A copper head gasket was used. No leaks after 3 weeks. Thank goodness.
THANK YOU to all the folks who provided info. and encouragement.

[1952henry]

Well done.

[Planojc]

Always good to get feedback on a problem solved. Good job.