Drilling out ARP crank bolt?
Thread Starter
Teching In
Joined: Aug 2014
Posts: 17
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To clarify, yes I did use the moly lube from ARP. Right now, the engine is on a stand with the pulley and crank gear on it, and the bolt a few turns away from the pulley. It turns a little in both directions, but nothing more than that - even with my halfway decent electric impact. I didn't drill very far, just enough to know that the ARP bolt isn't made of compressed diamond like everyone thinks.
I picked up a huge 3/4 breaker today and a propane torch, I figure I'll try to wrench it out the rest of the way before doing anything else. Maybe I should plasma the flange off so I can get the pulley out of the way first? I feel like heating the outside of the pulley isn't going to get the heat where it needs to be, but I guess that's worth a try. If it breaks, I guess I'll give up and go get a stroker crank or something.
I picked up a huge 3/4 breaker today and a propane torch, I figure I'll try to wrench it out the rest of the way before doing anything else. Maybe I should plasma the flange off so I can get the pulley out of the way first? I feel like heating the outside of the pulley isn't going to get the heat where it needs to be, but I guess that's worth a try. If it breaks, I guess I'll give up and go get a stroker crank or something.
Heli-coils come in various lengths, denominated by "d" or diameter. Most off the shelf heli-coils are 1d or the length of 1 bolt diameter. You can get 2d, which is twice the bolt diameter and stronger then the tensile strength of the bolt. You would need to shop on line to find it and likely from an industrial supply house.
Hi Natesully
See if you can get a 4" grinder or a smaller cut off wheel in to where the bolt is and cut the bolt flange off so you can pull the balancer off. Then you should be able to heat the crank snout and try to remove the bolt but I don't much hope for that as you have gaulded the threads and that is why the bolt only moves the little bit that it does. At this point if this is a stock motor then I would just get a new crank after all the time and money to fix it not worth it and a Helicoid wont have the thread engagement that the OEM has and not as strong.
Good luck Dave
See if you can get a 4" grinder or a smaller cut off wheel in to where the bolt is and cut the bolt flange off so you can pull the balancer off. Then you should be able to heat the crank snout and try to remove the bolt but I don't much hope for that as you have gaulded the threads and that is why the bolt only moves the little bit that it does. At this point if this is a stock motor then I would just get a new crank after all the time and money to fix it not worth it and a Helicoid wont have the thread engagement that the OEM has and not as strong.
Good luck Dave
Speaking from personal experience, during a Novice cam install I forgot to put the washer on the ARP bolt, this resulted in it bottoming out in the crank and seizing up.
I opted out of attempting to drill it, instead I used a 6 foot long, 1" torque wrench and a 2ft cheater pipe on that, with the help of my father we managed to sheer the bolt off completely(about 3/4" stayed in the crank) I then took the stock bolt, cut off 1" and covered it in anti seize, ran it in and out of the crank a few times and finally torqued it to 240ft lbs..that car ran till the day it was totaled with no issues.
Obviously you've started drilling already so good luck, it'll be hard to get it right that way.
I opted out of attempting to drill it, instead I used a 6 foot long, 1" torque wrench and a 2ft cheater pipe on that, with the help of my father we managed to sheer the bolt off completely(about 3/4" stayed in the crank) I then took the stock bolt, cut off 1" and covered it in anti seize, ran it in and out of the crank a few times and finally torqued it to 240ft lbs..that car ran till the day it was totaled with no issues.
Obviously you've started drilling already so good luck, it'll be hard to get it right that way.
I've scanned this whole thread and one thing that concerns me is that fact that the OP said he was hammering the pulley on the crank. I had a buddy that did the exact same thing and the motor didn't last very long...I personally think it was from pounding on the end of the crank with a hammer.
When I installed my Powerbond Pulley, we used the tool and got the pulley seated correctly, but somehow managed to cross thread the ARP bolt and got stuck too. We ended up using the 3'-4" pipe on a breaker bar and managed to back the ARP bolt out. Of course the threads in the crank were messed up, but we were able to save it. CAT, yes, the industrial equipment manufacturer makes bolts that are the same thread pitch as the stock crank bolt. I bought a longer bolt, used thick spacers, and my pulley has been installed that way for the past 8-9 years without any issues. We did use a thread chaser and clean out the crank threads as best we could, but the longer bolt and spacers has worked without any issues for years.
I made a thread about it when all this happened, so search my username and something about a CAT bolt or something like that and you may find my original post with part numbers included.
When I installed my Powerbond Pulley, we used the tool and got the pulley seated correctly, but somehow managed to cross thread the ARP bolt and got stuck too. We ended up using the 3'-4" pipe on a breaker bar and managed to back the ARP bolt out. Of course the threads in the crank were messed up, but we were able to save it. CAT, yes, the industrial equipment manufacturer makes bolts that are the same thread pitch as the stock crank bolt. I bought a longer bolt, used thick spacers, and my pulley has been installed that way for the past 8-9 years without any issues. We did use a thread chaser and clean out the crank threads as best we could, but the longer bolt and spacers has worked without any issues for years.
I made a thread about it when all this happened, so search my username and something about a CAT bolt or something like that and you may find my original post with part numbers included.
I've scanned this whole thread and one thing that concerns me is that fact that the OP said he was hammering the pulley on the crank. I had a buddy that did the exact same thing and the motor didn't last very long...I personally think it was from pounding on the end of the crank with a hammer.
When I installed my Powerbond Pulley, we used the tool and got the pulley seated correctly, but somehow managed to cross thread the ARP bolt and got stuck too. We ended up using the 3'-4" pipe on a breaker bar and managed to back the ARP bolt out. Of course the threads in the crank were messed up, but we were able to save it. CAT, yes, the industrial equipment manufacturer makes bolts that are the same thread pitch as the stock crank bolt. I bought a longer bolt, used thick spacers, and my pulley has been installed that way for the past 8-9 years without any issues. We did use a thread chaser and clean out the crank threads as best we could, but the longer bolt and spacers has worked without any issues for years.
I made a thread about it when all this happened, so search my username and something about a CAT bolt or something like that and you may find my original post with part numbers included.
When I installed my Powerbond Pulley, we used the tool and got the pulley seated correctly, but somehow managed to cross thread the ARP bolt and got stuck too. We ended up using the 3'-4" pipe on a breaker bar and managed to back the ARP bolt out. Of course the threads in the crank were messed up, but we were able to save it. CAT, yes, the industrial equipment manufacturer makes bolts that are the same thread pitch as the stock crank bolt. I bought a longer bolt, used thick spacers, and my pulley has been installed that way for the past 8-9 years without any issues. We did use a thread chaser and clean out the crank threads as best we could, but the longer bolt and spacers has worked without any issues for years.
I made a thread about it when all this happened, so search my username and something about a CAT bolt or something like that and you may find my original post with part numbers included.
https://ls1tech.com/forums/southern-...endations.html
Thread Starter
Teching In
Joined: Aug 2014
Posts: 17
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Hey, yeah, that CAT bolt sounds like what I'm gonna need. Thanks for the tip!
So, I broke the bolt off in the crank. Saw that one coming
. I went ahead and drilled a hole through the remaining piece, and made sure I can get an easy-out to grip on it. Yes, you can drill through the ARP bolts, it just takes a while. I used a 12mm socket as a drill guide for a 5/16 bit, which worked pretty good, actually. I also went quite slow and used WD-40 to keep the bolt and bit cool.
My plan for tomorrow is to drill the front part of the bolt out all the way, and hopefully remove the offending thread that's holding it in. If I can get it to spin freely, hopefully I can clean the threads up with a tap then spin it out of the crank.
So, I broke the bolt off in the crank. Saw that one coming
. I went ahead and drilled a hole through the remaining piece, and made sure I can get an easy-out to grip on it. Yes, you can drill through the ARP bolts, it just takes a while. I used a 12mm socket as a drill guide for a 5/16 bit, which worked pretty good, actually. I also went quite slow and used WD-40 to keep the bolt and bit cool.My plan for tomorrow is to drill the front part of the bolt out all the way, and hopefully remove the offending thread that's holding it in. If I can get it to spin freely, hopefully I can clean the threads up with a tap then spin it out of the crank.
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Brett Foote
Staging Lane
Joined: Feb 2015
Posts: 69
Likes: 1
From: st-hyacinthe, qc canada
solid carbide drill will drill it like butter. start with 1/4" hole and follow with a bigger one but leave some material to avoid hurting the treads, it's not that easy to drill straight with a hand drill. take the torch and heat inside the hole just enuff to change the color of the remaining bolts, this should not harm the crank snout if done properly. let it cool and use an extractor. IF you are really handy with a welder you can weld a bolt Inside the hole, it will shrink the broken bolt and help free it. once remove, use a tap to clean up the hole, if you're Lucky the treads might be saved
http://www.hotrod.com/how-to/engine/...shaft-threads/
here this guy fixes threads on crankshaft. might be useful
here this guy fixes threads on crankshaft. might be useful
Hey, yeah, that CAT bolt sounds like what I'm gonna need. Thanks for the tip!
So, I broke the bolt off in the crank. Saw that one coming. I went ahead and drilled a hole through the remaining piece, and made sure I can get an easy-out to grip on it. Yes, you can drill through the ARP bolts, it just takes a while. I used a 12mm socket as a drill guide for a 5/16 bit, which worked pretty good, actually. I also went quite slow and used WD-40 to keep the bolt and bit cool.
My plan for tomorrow is to drill the front part of the bolt out all the way, and hopefully remove the offending thread that's holding it in. If I can get it to spin freely, hopefully I can clean the threads up with a tap then spin it out of the crank.
So, I broke the bolt off in the crank. Saw that one coming
. I went ahead and drilled a hole through the remaining piece, and made sure I can get an easy-out to grip on it. Yes, you can drill through the ARP bolts, it just takes a while. I used a 12mm socket as a drill guide for a 5/16 bit, which worked pretty good, actually. I also went quite slow and used WD-40 to keep the bolt and bit cool.My plan for tomorrow is to drill the front part of the bolt out all the way, and hopefully remove the offending thread that's holding it in. If I can get it to spin freely, hopefully I can clean the threads up with a tap then spin it out of the crank.
Double check me on this. The drill size for tapping is 15mm (0.59") so the 1/2" drill may not be big enough. You may want to creep up one size at a time and watch for the crank threads each time.
Last edited by vettenuts; Mar 17, 2015 at 06:28 AM.
On The Tree
Joined: May 2014
Posts: 179
Likes: 0
From: FortLauderdale/Orlando
As you already know, bolt won't be that hard to drill out. In the future, running a file over the material in question will tell you if its going to be a nightmare or not.
My suggestion would be to buy a "timesert" repair kit.
Seeing the word "helicoil" makes me cringe...
Thrust bearings are your friend.
Subtract thread pitch from the diameter and you have your tap/drill size (metric)
My suggestion would be to buy a "timesert" repair kit.
Seeing the word "helicoil" makes me cringe...
Thrust bearings are your friend.
Subtract thread pitch from the diameter and you have your tap/drill size (metric)
Thread Starter
Teching In
Joined: Aug 2014
Posts: 17
Likes: 0
Got it!
I tapped the remains of the ARP bolt out today, and torqued an old one down to 200 ft-lbs (all I could manage without flipping the stand) to test my... slightly used threads.
So, for posterity, here's what I did-
1. Use a 12mm socket, that just fits the crank bore, to guide a 5/16 bit to the middle of the broken bolt piece. Point the ratchet end, with the hole in it, toward the bolt so the guiding part is as close to the bolt as possible. Drill through. The hole should be centered almost perfectly. Don't forget to use WD-40 or something to keep the bolt/bit clean and cool, and apply moderate pressure as you go.
2. Go to a 1/2 bit, drill through with that.
3. Finally, drill through with a 14mm bit. Be careful, you are going to be right up on the threads. At this point, there's pretty much just threads left from the bolt.
4. Use the 16x2 long shank tap you can get on Amazon/Ebay to tap out the remains of the bolt, and clean up the threads for good. Use duster/compressed air to keep the shavings out of the hole as you tap, backing out the tap every so often to clean it.
I tapped the remains of the ARP bolt out today, and torqued an old one down to 200 ft-lbs (all I could manage without flipping the stand) to test my... slightly used threads.
So, for posterity, here's what I did-
1. Use a 12mm socket, that just fits the crank bore, to guide a 5/16 bit to the middle of the broken bolt piece. Point the ratchet end, with the hole in it, toward the bolt so the guiding part is as close to the bolt as possible. Drill through. The hole should be centered almost perfectly. Don't forget to use WD-40 or something to keep the bolt/bit clean and cool, and apply moderate pressure as you go.
2. Go to a 1/2 bit, drill through with that.
3. Finally, drill through with a 14mm bit. Be careful, you are going to be right up on the threads. At this point, there's pretty much just threads left from the bolt.
4. Use the 16x2 long shank tap you can get on Amazon/Ebay to tap out the remains of the bolt, and clean up the threads for good. Use duster/compressed air to keep the shavings out of the hole as you tap, backing out the tap every so often to clean it.