crank threads stripped...need help..........................
crank threads stripped...need help.......................... guy at work just got done with a cam swap in his camaro. Got it all put back together and the new crank bolt only threads in a few threads and gets stuck. He bought another new bolt just to be sure and its the same thing...
He didnt try to force it but can this be fixed? He said he got ahold of a guy at the machine shop and said their tappers arent deep enough???
any options? Please let me know.
didnt know if GM could fix this or not...
I would try to search it, but all i get is a blank screen...
Thanks in advance.
Keegan
He didnt try to force it but can this be fixed? He said he got ahold of a guy at the machine shop and said their tappers arent deep enough???
any options? Please let me know.
didnt know if GM could fix this or not...
I would try to search it, but all i get is a blank screen...
Thanks in advance.
Keegan
Banned
Joined: Aug 2006
Posts: 326
Likes: 0
From: North Bay, CA
I'm not understanding how the shop could say that their taps are not long enough....I have put a tap through a 12" block before, you just use a tap socket with an extension. It's good that you guys didn't try to force the bolt in like many others would 
Call another shop or get a tap and socket yourself make sure to put lube on the tap, and work it forwards and backwards when you hit the bad threads.
Call another shop or get a tap and socket yourself make sure to put lube on the tap, and work it forwards and backwards when you hit the bad threads. 
TECH Addict
Joined: Dec 2001
Posts: 2,907
Likes: 1
From: Bergen County, NJ
Yes with the right tap you clean up the threads. I just can't understand why with all the threads on here about stripped and broken bolts anyone is still pulling the pulley on with a bolt.
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I don't believe a tap is going to do much good if he doesn't use a longer bolt afterwards. If you take a longer bolt(120mm) and screw it all the way in it will bottom out. That tells me there isn't room for any more threads in the bolt hole. Maybe just using a thread chaser instead of a tap to remove burrs and then use a longer bolt will work. A threaded rod is obviously the way to go to push the pulley back on. You can screw it in all the way until it bottoms out and the pull the pulley on with the maximum amount of purchase on the available threads. Short of that I've been using a 120mm bolt for years with a 100% sucess rate. It gives you 17mm of extra thread purchase over the OEM bolt. I push the pulley on until the longer bolt bottoms out and then switch to the shorter OEM bolt to shove the pulley home. I guess I should spring for the threaded rod tool considering I purchased about 6 spring compressor tools until I finally spent a hundred bucks to get the Vinci/Crane which is the best of anything out there. I could have purchased several pulley pusher tools with the money I've spent on spring compressor tools over the years.
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So how did this happen? The bolt unthreads effortlessly once it's cracked... did you guys try putting it on with the longer bolt or did you strip it by not getting the pully on far enough and then trying to tighten it down? You need atleast 6 - 7 good turns on the bolt before it has enough thread to grab and not strip. Never use the longer bolt method, it's the most easy way to jack crap up. I heat the pully up where it goes on with a torch, then seat it by hand on the edge. Then I get a piece of wood and put it over the pully and use a rubber mallot to evenly displace force on the pully to where I can get it seated enough to get the stock bolt in. I then tighten it down as far as it will go with that bolt... remove it, then use the new bolt to torque it down the rest of the way using blue locktite! Works like a charm every time!
If i were you, i'd try cleaning the threads with a loose tap, if you really didn't do it by using the wrong method, it's possible some debris or something got on the threads not letting it go in. I did this one time with a spark plug hole that I totally jacked up cause I couldn't get the right angle for the plug..I was nervous cause it was my first head swap. haha. If that doesn't work, try the method above! Just make sure you need to do that before you go crazy with it!
If i were you, i'd try cleaning the threads with a loose tap, if you really didn't do it by using the wrong method, it's possible some debris or something got on the threads not letting it go in. I did this one time with a spark plug hole that I totally jacked up cause I couldn't get the right angle for the plug..I was nervous cause it was my first head swap. haha. If that doesn't work, try the method above! Just make sure you need to do that before you go crazy with it!
Originally Posted by DaddySS
........I just can't understand why with all the threads on here about stripped and broken bolts anyone is still pulling the pulley on with a bolt.
I don't think a tap is going to work because it won't be long enough. You will need an extender tool to get the longer reach because the first threads are recessed back into the crank snout and it is unlikely an extender tool would fit into the bolt bore. Hasn't it become apparent by now that some people shouldn't be removing/ installing their own pulley. The cost of a replacement crankshaft is far greater than hiring someone to who knows what they are doing to remove/install the pulley. I'm opposed to the heat method(torch,oven,etc.) because of the potential damage to the rubber crank timing cover seal. If you apply sufficient heat to the pulley to expand it enough that it slides onto the crankshaft easily there is certainly enough residual heat left in the pulley to distort the rubber seal where the pulley snout contacts the rubber timing cover seal. I've been using the 120mm bolt for years with success. I know this isn't the ideal method so I finally got out the checkbook and wrote a check for $44 for the special tool made for the LSx series engines. Anyone want to buy a 120mmX16mmX2mm bolt real cheap(slightly used)?
If needed I have a been also making a tap with a drive extension that will let you get the tap inside of the crank, to clean out the threads.
Shoot me a pm if interested.
Shoot me a pm if interested.
Last edited by 618HAWK; Aug 17, 2007 at 12:57 PM.
All this pull pullies on by the bolts is wrong stuff is funny. Ive done 50 cam swaps never a problem. You just have to be smarter than your tools! Some guys odn't get you need to lube the pully and crank. also if your only getting 3 threads on the bolt its not enough. heat the pully and push it on just until its about to touch the gasket. then lube everything again and pull it on while its still warm... not hot or it will warp the gasket.
Anyway to the original poster. If you can get it to turn in a few threads than make a chase( if you cant buy one) by cutting 4 small grooves in a stock bolt. then thread it in slowly it should fix the few messed up threads. If it doesn't feel right stop and run the tap threw it.
Anyway to the original poster. If you can get it to turn in a few threads than make a chase( if you cant buy one) by cutting 4 small grooves in a stock bolt. then thread it in slowly it should fix the few messed up threads. If it doesn't feel right stop and run the tap threw it.
Originally Posted by ShiznityZ28
All this pull pullies on by the bolts is wrong stuff is funny. Ive done 50 cam swaps never a problem. You just have to be smarter than your tools! Some guys odn't get you need to lube the pully and crank. also if your only getting 3 threads on the bolt its not enough. heat the pully and push it on just until its about to touch the gasket. then lube everything again and pull it on while its still warm... not hot or it will warp the gasket.
i guess when he was pulling the pulley off he was using the stock bolt for the puller to push on...I guess it stripped sometime during that...bolt came out fine he said. He never tried to put the new pulley on even. He took the new bolt just for the heck of it and tried to thread it in....no go....
Originally Posted by TRU-2GM
i guess when he was pulling the pulley off he was using the stock bolt for the puller to push on...I guess it stripped sometime during that...bolt came out fine he said. He never tried to put the new pulley on even. He took the new bolt just for the heck of it and tried to thread it in....no go....
i use a bolt from my super charger kit , that i used to pin the crank to with. it works great! its a good bit longer , just put a little lube on it, thread it on , pull the balancer on, then put the new bolt in. procharger, superchargersforless.com, and any newer high perf. shop sells them. ive got an extra one. pay for shipping and you can have it.
Well I haven't done my 1st LS1 cam swap yet but I'm getting close. I got this pulley install tool for $44 shipped from an LS1 member. The welds look great and I can't wait to use it: https://ls1tech.com/forums/removed-locked-thread-graveyard/391883-new-crank-dampener-installation-tool-pics.html
I use a BIG allen head cap screw to buck the puller rod up against with a couple of large flat washer under the head of the allen screw that are just slightly smaller than the O.D. of the crankshaft. The hex in the allen screw gives the point on the puller rod a place to seat and forces the rod to be self-centering so it doesn't try to walk all over the place while your tighening down on the puller. If you don't have a BIG allen head cap screw you can use a large bolt(not so large that it touches the threads in the crank) with flat washers under the head. You can drill a dimple in the head of the bolt to give the puller rod a place to seat itself so it doesn't try to walk as you remove the pulley.
