HELP! Drilled too far to remove broken flywheel bolt

[Atrus]

Hoping I am OK, but I am thinking I am not F*(K


Ended up snapping one of my crank bolts, don't even ask how. Fail #1. Drilled for an EZ-Out, which was too small for the job, and right as I was thinking I should back it out and go 1 size larger, I snapped it off. Fail #2. Ended up actually being able to drill a bigger hole back through the bolt (was amazed it actually worked with the broken EZ out in there), but then noticed my completely moronic ass drilled too deep and got into the block behind the crank! Epic Fail #3.

I'm not sure where to go from here now. Rough measurements -

Face of crank to non-effed up block surface: ~7/8"

Face of crank to the bottom of my dumbass hole: ~1-3/8". Drill bit diameter is 3/16".

So, I basically have a f*(king 3/16" dia, .5" deep hole in the back of my block, right?


How thick is the block at the rear of the engine?
What's behind the crank there? Isn't it the reluctor wheel?
What happens if there IS a hole right though the block?
Is there an oil galley or anything back there? Can I start the engine with no flywheel to see if I have any leaks?

Any other advice? I absolutely cannot believe I did this. Such a ridiculously dumbass move, and I am guessing, a very expensive mistake now.

[c0ncEpT]

If its not leaking anything its more than likely ok. I have used a sawzal to mod more than a few LS1 blocks.

[Atrus]

It's not leaking now...can I/should I start it with the flywheel off and see what happens?

Edit - the car's been sitting for two weeks also.

[Atrus]

And, yeah - dumb question. Of course I can't start it with it off....

[farmington]

as long as there isn't an oil galley there, and I don't think there is, you should be good. If you decide to start it, it would probably be best with the flywheel on it.

[Atrus]

Do you guys think I should make an attempt to seal it up, or it is more or less sealed because of the rear main?

Basically, imagine a 3/16" hole drilled right through the center of where one of the flywheel bolts are. If it helps, it's at about "9:30" or "10:00" on the engine.

[Atrus]

Cleaned it up, here's a pic. The "cross hatch" line would be the rear of the block. I did punch though:

[1BADAIR]

Most of the flywheel bolts require Blue/thread sealer because they are open. I would try to get the burrs off then Teflon paste or gm blue loctite/thread sealer the bolt to seal it.
Thts not the block. It's th crank

[Atrus]

Most of the flywheel bolts require Blue/thread sealer because they are open. I would try to get the burrs off then Teflon paste or gm blue loctite/thread sealer the bolt to seal it.
Thts not the block. It's th crank

The crank is the M10 (or is it M11?) threaded steel cylinder up front, which I have new thread sealed GM bolts for. Behind it though, the rough milled aluminum piece that I drilled though is the crank also? I'm pretty sure that's the back of the block.

I got a 1/4" long M6 set screw that I'll tap/thread into the 3/16" hole.

I am a little nervous (when am I not about something?) about all the metal shavings - I'll clean up as best I can, but I hope those don't cause a rear seal failure down the road (or immediately).

[Atrus]

Definitely the block, because then I spun the crank a little to line up my $1 flywheel holder (this one I am kinda proud of), the hole I drilled stayed static while the crank spun.

I tapped a M6x1.25 thread in there and put in a ~1/4" stainless set screw and used red lock tite. Hopefully I am good to go now.

Set Screw:


$1 flywheel holder:

[DETROITMUSCLE]

the fix looks good, same thing I would have done.

[Atrus]

Thanks - sure hope it's OK!

Bellhousing is back on...slave is bolted up...about to install the remote bleeder, and then the trans will be back up on it's way in!

[1BADAIR]

how are you gonna get the metal and alum out?

[Atrus]

how are you gonna get the metal and alum out?

Out of? I cleaned up everything as best I could with brake cleaner and compressed air. I also didn't thread all the way through the hole in an effort to keep shavings out of the oilpan. Cut threads just deep enough to allow the set screw to sink in.

I can drain the oil before I fire it up in an attempt to get any shavings out.

If there's anything else I should do now or should have done, please let me know before I have the trans torqued back in. I am about to torque the trans-to-bellhousing bolts and continue on with the reinstall.

[Atrus]

If people have any advice/recommendations, please lay 'em out there, I am all ears at this point!