Retapping 91 3FE Engine Block after breaking push rod cover bolt inside the hole (1 Viewer)

[mobalatero]

Was finishing up with the push rod/side cover gasket replacement and simply over-torqued the first bolt and broke the head off the bolt. To make matters worse, tried to use an extractor to pull out the broken bolt and ended up breaking the extractor inside the broken bolt inside the block . Luckily, it was the middle top bolt which is the most accessible bolt hole of them all. Not sure what I would have done if it were any of the bolts towards the back. Likely would have had to pull the engine.

Went down a rabbit hole on the best way to drill out a broken extractor inside a broken bolt and a Dremel with a diamond bit worked the best for me. 2 diamond bits later and it's out. Now I'll need to drill and tap the block as the threads are all chewed away from the Dremel. What are my options? Helicoil? Time Sert? Does anyone know what size/pitch I need?

 

[Malleus]

M6x1.0

With a thread this small (installed torque this low), it doesn't matter what thread replacement you use. Get whichever is most cost effective for you and easiest to get your hands on.

 

[jonheld]

From the Toyota FSM:

 

[mobalatero]

From the Toyota FSM:

View attachment 3331910

Used a 1/4-inch torque wrench to get to the spec above and still it broke somehow. Had better luck doing it by hand/feel.

 

[CharlieS]

This doesn't help your situation, but in the future, and for others, welding a nut to the fasteners can often work well to get the broken part out without damaging the threads. I literally threw away that style of extractors years ago, they are brittle and more often than not create more work than they save.

 

[Mixelplix]

I would just drill and tap to the next size up, personally.

 

[inkpot]

I would just drill and tap to the next size up, personally.

Exactly, if you don't mind having 1 oversized bolt. Otherwise just use a Helicoil type repair.

 

[jonheld]

Used a 1/4-inch torque wrench to get to the spec above and still it broke somehow. Had better luck doing it by hand/feel.

That torque spec assumes a new cork gasket.

 

[mobalatero]

Quick update. Grabbed a helicoil repair kit from a local NAPA auto parts store and successfully repaired the threads.

Avoided the torque wrench this time and did all the bolts by hand/feel and was successful. Thanks for everyone’s help.

 

[mobalatero]

That torque spec assumes a new cork gasket.

Yes, confirming I installed a new cork gasket.