stripped crankshaft

i have a 94 s-10 blazer 4.3L vortec...i was putting my vibration damper bolt back in place and i was torquing it to the 70ftlbs stated in the repair manual and as i was tightning it by some freakin chance in hell the threads in the crankshaft stripped... i tried retapping it but the threads actually came out when it stripped.... would it be possible to drill out the shaft wiht a 31/64" drill bit(the hole is curently 7/16") then tap it with a 1/2" fine thread tap... Or should i not be messing wiht stuff like that and just take it to the dealership now..if it is possible to do it myself have any suggestion on what to use for a drill i tried both of my cordless drills but the are all a little bit to long with that bit... i pulled the bottom fan guard off already and now my drill is hitting the one rail that runs underneath the rad.... any suggestions??

don't drill the crank it will cause balance problems. your best bet is to get a new crank and bearings and seals for the lower half of the motor, then take it to a mechanic,s shop to have it rebuilt.

i only say take it to a shop cause anyone that will drill the crank doesn't know alot about engines and should have a pro do a rebuild for them.

I am not extremely familiar with the problem, but wouldn't it cause NO balance problems if it is just in the axial direction of the crankshaft? I'm assuming this is on the end of the crankshaft and you are bolting something to it via a tapped hole in the end. Therefore, it's just a larger hole, and I can't really see a problem. Then again, I'm not familiar with the problem. Please correct me if I'm wrong.

i have a 94 s-10 blazer 4.3L vortec...i was putting my vibration damper bolt back in place and i was torquing it to the 70ftlbs stated in the repair manual and as i was tightning it by some freakin chance in hell the threads in the crankshaft stripped... i tried retapping it but the threads actually came out when it stripped.... would it be possible to drill out the shaft wiht a 31/64" drill bit(the hole is curently 7/16") then tap it with a 1/2" fine thread tap... Or should i not be messing wiht stuff like that and just take it to the dealership now..if it is possible to do it myself have any suggestion on what to use for a drill i tried both of my cordless drills but the are all a little bit to long with that bit... i pulled the bottom fan guard off already and now my drill is hitting the one rail that runs underneath the rad.... any suggestions??

how about just retapping with the next tap size up. I would think as long as the hole is still straight (just no threads left in the hole) it would not have a balance problem.

Helicoil maybe? A good repair shop should certainly be able to save you from rebuilding the engine with a new crank.

if the tapped hole is bigger the dyed threads would need to be the larger size also

how about just retapping with the next tap size up. I would think as long as the hole is still straight (just no threads left in the hole) it would not have a balance problem.

I did this with 1 motor, and it worked great. I used permanant lock tight to be on the safe side

i would get a machine shop to drill and tap the crank. they have high quality drill bits and taps. you don't want to break a tap in the crank. oh yeah the next time you install a vibration dampener clean the mating surfaces and put some grease on the nose of the crank.

if you drill and tap it yourself if you drill it crooked it would cause the vibration damper to mount akward, this would cause a misbalance, i would just have someone tap it bigger or put a helicoil in it, that way you dont break tools off in it and it wouldnt be your fault so you wouldnt be liable to take care of it.

I wouldnt think there would be a balance problem, since the balancer slides over the end of the crankshaft and you wouldnt be disturbing the round surface of the crank. The bolt just keeps the balancer from coming off the end the crank.