Broken crank bolt in crankshaft, Disaster?
Thread Starter
TECH Junkie
Joined: Nov 2001
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From: Los Angeles
Broken crank bolt in crankshaft, Disaster? I know I've seen it before on here, but who else has had a crank bolt break off in the crank snout, and what did you have to do to fix it? Some friends just called me saying this had happened (due to a miscalculation) and I honestly didn't have much of an idea besides "you're screwed".
They had to use a breaker bar to back the bolt out after seating the crank pulley, it was that bad...and finally it just snapped...none of the bolt is sticking out, its all inside the crank. Its a hardened aftermarket bolt too, not the stock one (which is why all this happened, as they were seating with the longer bolt! DOH! Seat with the stock bolt, only use the long bolt to get it started!).
They had to use a breaker bar to back the bolt out after seating the crank pulley, it was that bad...and finally it just snapped...none of the bolt is sticking out, its all inside the crank. Its a hardened aftermarket bolt too, not the stock one (which is why all this happened, as they were seating with the longer bolt! DOH! Seat with the stock bolt, only use the long bolt to get it started!).
There are some places that use some kind of high pressure water blast to get broken bolts out of stuff, I looked into it when I broke a header bolt off in my 700 mile 2002 Z28s cylinder head. I guess that the water doesn't hurt the head (or crank in this case). Also, it can surely be drilled out and the crank retapped, but I would think it would have to come out of the engine for that, but there may be enough room to get a 90* drill in there...
Either way, its probably gonna be a pain in the azz.....
Either way, its probably gonna be a pain in the azz.....
TECH Resident
Joined: Jan 2002
Posts: 865
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From: central TX
Originally Posted by JoeDirt
Couldnt you drill it and use a big "easy out" bit to remove it ?? Id try that first .
This is going to be the first thing I try...tomorrow. What a long & crappy day this has been.
Now...what if I *can't* get it out? I'm fairly **** about my car, so I probably couldn't be convinced to use any used parts...
1. Drop the kmember, tranny, oil pan...remove the crank from the bottom & replace? What all do I need - crank - new main bearings? what else?
2. Drop the tranny...remove the heads & intake...remove & replace the short block? (I know this would be drastic, but would it save a lot of work? Then I could sell the stock shortblock - even with the 'gimpy' crank)
3. ???
*sigh*
Shane
TR224 in car...car dead.
TECH Enthusiast
Joined: Aug 2003
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I think youll get it out if you can just get a good bite on it . What f you get the easy out in there and mig on a bolt than just spin it out with an impact gun . That bolt must have been brittle like a **** .
Look around there is a place around here called witt Disintegration DON'T try to use a tap, it will never come out. You will just have a broken tap in your crank also. They can disintegrate the bolt in the crank without ruining any threads! It works awsome!
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TECH Resident
Joined: Jan 2002
Posts: 865
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From: central TX
You know, I took this as a joke, but how likely is this? The pulley is completely seated on the crank snout.
After further inspection, the bolt did not snap off flush with the crank, but actually snapped off about 2 inches *in* the crank snout, right where the threads start. Could I helicoil a smaller bolt in the 2 inch smooth section to help hold the pulley on? And why does the pulley have to be held on with a 240lb/ft torqued bolt?
*sigh*
Shane
Originally Posted by Terry Burger
Just leave it, the pulley might never fall off! lol 
After further inspection, the bolt did not snap off flush with the crank, but actually snapped off about 2 inches *in* the crank snout, right where the threads start. Could I helicoil a smaller bolt in the 2 inch smooth section to help hold the pulley on? And why does the pulley have to be held on with a 240lb/ft torqued bolt?
*sigh*
Shane
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TECH Addict
Joined: Dec 2001
Posts: 2,907
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From: Bergen County, NJ
I couldn't tell from your description if you were tightening or loosening the longer bolt, hopefully tightening. If that's the case, it should come out easily once you drill enough to get an easy out to grip. If you were trying to back it out with a breaker bar and it snapped then you are in for a rough time.
Last edited by DaddySS; Dec 7, 2003 at 09:37 AM.
Staging Lane
Joined: Nov 2002
Posts: 97
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From: THE MOTOR CITY
i don't know that puling the crank out of the bottom of the engine is a good idea.
if you have to remove the crank, it would be best to just tear the thing down all the way. At least this way you can add some forged goodies if you want.
if you have to remove the crank, it would be best to just tear the thing down all the way. At least this way you can add some forged goodies if you want.
Originally Posted by Shane
And why does the pulley have to be held on with a 240lb/ft torqued bolt?
*sigh*
Shane
*sigh*
Shane
If you follow this method every time, you'll never have a thing to worry about.
*If you can't get the old bolt started when seating the pulley, use the longer threaded rod method to get the pulley on the snout, then pull this bolt out and put in the stock, used bolt and complete the procedure above.*
TECH Resident
Joined: Jan 2002
Posts: 865
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From: central TX
Excellent. Forgive me if I'm not thinking clearly right now - I'm still a little freaked out. Do you think a helicoil & a smaller bolt will be enough to keep the pulley on now?
The problem we had was that we used the longer threaded rod (bolt actually) to pull the pulley completely on. There were washers on the longer bolt to keep it from bottoming out - and it had been used on multiple cars before for this.
In any case, it's done now, and I need to figure out what to do next...
thanks,
Shane
Do you think a helicoil & a smaller bolt will be enough to keep the pulley on now?The problem we had was that we used the longer threaded rod (bolt actually) to pull the pulley completely on. There were washers on the longer bolt to keep it from bottoming out - and it had been used on multiple cars before for this.
In any case, it's done now, and I need to figure out what to do next...
thanks,
Shane
Originally Posted by CANNIBAL
It's not held on with a 240 lb/ft torque. The pulley is seated on to the crank snout by applying a total of 240 lb/ft torque to the stock, used crank bolt. This is the GM spec for being sure you have pushed the pulley onto the snout the proper distance. Then you put in the new bolt, torque it to 37 lb/ft, then you need to turn it an additional 140* to stretch the bolt to provide the torque it needs to hold the pulley onto the crank snout.
If you follow this method every time, you'll never have a thing to worry about.
*If you can't get the old bolt started when seating the pulley, use the longer threaded rod method to get the pulley on the snout, then pull this bolt out and put in the stock, used bolt and complete the procedure above.*
If you follow this method every time, you'll never have a thing to worry about.
*If you can't get the old bolt started when seating the pulley, use the longer threaded rod method to get the pulley on the snout, then pull this bolt out and put in the stock, used bolt and complete the procedure above.*
Man I feel you. I put in my Pilot bushing in my crank wrong and ended up pushing the freeze plug thats in the end of the crank all the way out.
If it was me I would call MTI and get a stock crank that was pulled out of a car that they put stroker kits in. They normally have a some good cores and they will sell them pretty cheap. Since you were trying to back the bolt out and it broke doesnt sound like normal methods will take it out.
On second though you said you only wanted new parts in your car. Sounds to me like a good path would be.
Eagle 4" crank $1000 (check sponsors)
Eagle 6.100 or 6.125 rods $400 (they're not a sponsor, PM me)
JE or Diamond pistons $850 (any Sponsor)
Federal Mogul bearings $110 (Summit)
Total $2360
Just my $0.02
If it was me I would call MTI and get a stock crank that was pulled out of a car that they put stroker kits in. They normally have a some good cores and they will sell them pretty cheap. Since you were trying to back the bolt out and it broke doesnt sound like normal methods will take it out.
On second though you said you only wanted new parts in your car. Sounds to me like a good path would be.
Eagle 4" crank $1000 (check sponsors)
Eagle 6.100 or 6.125 rods $400 (they're not a sponsor, PM me)
JE or Diamond pistons $850 (any Sponsor)
Federal Mogul bearings $110 (Summit)
Total $2360
Just my $0.02
wel, I'd ure look into the disintegration thing, but how that would avoid harming the crank, I cant imagine. It would be almost impossible to weld a new bolt or rod on the end, like a head bolt, because it would be so tough to ground the crank.
If it were me? (and these things do happen to all of us... you've just been lucky for awhile now Shane ;-) ) I'd put it on a truck and ship it to MTI.
Its not going to be trivial, no matter what you do...
chris
If it were me? (and these things do happen to all of us... you've just been lucky for awhile now Shane ;-) ) I'd put it on a truck and ship it to MTI.
Its not going to be trivial, no matter what you do...
chris
TECH Resident
Joined: Jan 2002
Posts: 865
Likes: 1
From: central TX
Drilling & tapping didn't work. Now looking at pulling the crank (either remove the k-member & take it out the bottom, or pull the engine and work with it on a stand)...or sucking it up and taking to a shop.
No good LS1 shops in Austin though. I'm going to post in the TX section to see if I can get prices from places around here...like Houston...Dallas...?
Shane
No good LS1 shops in Austin though. I'm going to post in the TX section to see if I can get prices from places around here...like Houston...Dallas...?
Shane
A good machine shop can mill the bolt out without damaging the threads, but you would need to remove the crank from the engine. Another option would be to just weld the pulley to the crank snout and go with it until the next time you need to tear down the engine.
Originally Posted by JoeDirt
That disintegration thing sounds like a good cheap plan . How does that work without "disintigrating" everything ?
