Woodruff key keeps snapping
- Thread starter blaster02
- Start date
the nut that holds the flywheel on isnt tight enough. it takes a special tool to get it to the right amount of torque. mine kept doing the same thing, i took it in and had a dealer use the device that holds the flywheel in place and hit it with an impact wrench. no problems since.
Yea, hold the flywheel with the holder and TORQUE it to the proper spec!!!, they list torque specs for a reason!
Check to see if the inside taper of the flywheel is messed up from it spinning around on the crank. If there is anything there, this will be the thing that will keep you shearing the keys.
I have the same problem my key just keeps snapping and I noticed the threaded part of the crankshaft is slightly bent will ths effect it even thou I can still get the nut on as tight as I need to.
If you can "get the nut on as tight as you need to" then you wouldn't be having this problem. Are you using the large spacer/washer that goes on before the nut? If the end of the crankshaft is slightly bent then yes it can cause problems.Depends on how bad and how far it is bent. I would get some valve lapping compound and put a little on the taper of the crankshaft.Then install the flywheel without the woodruff key and spin the flywheel with pressure a bunch of times.This will clean up and resurface the taper on the crank and flywheel. Once thats done wipe it all off good. Then reinstall the flywheel and woodruff key,spacer/washer,and the nut.Then put the impact gun on it and make sure you get it as tight as you can.If you want to torque it feel free but a good impact always works best.IMO If this does not work then I would suspect a new crank is in order. Good luck
Make the taper mating surfaces are lapped cleanly.
Final lap can be made with No3 cut and polish, to make it smooth.
Completly clean all, and I mean, all grinding paste from the shaft and flywheel.
Torque the nut up to 53 ft lbs, no tighter, or you could pull the end off that bent thread.
It is not the nut that keeps it on, it is the interference fit between the components.
If the tapers are poor, and not mating, no amount of nut tightening will stop that flywheel spinning.
Final lap can be made with No3 cut and polish, to make it smooth.
Completly clean all, and I mean, all grinding paste from the shaft and flywheel.
Torque the nut up to 53 ft lbs, no tighter, or you could pull the end off that bent thread.
It is not the nut that keeps it on, it is the interference fit between the components.
If the tapers are poor, and not mating, no amount of nut tightening will stop that flywheel spinning.
Thanks a lot guys I'll try it when the new woodruff keys arrive as I've ran out as soon as I try it I'll let you know how I got on thanks a lot
was it the stock key or +4 that you had problems with? im curious cause both were fine for me...
Sorry it's abit late but I sorted the problem I put valve lapping compound on worked it in really well cleaned it off new key did the nut up with an impact wrench and it's been fine ever since thanks for the advice guys really appreciate it
thank you for actually telling people that the problem has been solved. and what the issue was. this teaches everyone.
Impact driver to an unknown tension , NO.
Tension wrench to 53 ft lbs YES.
If you have over tensioned the flywheel on, it is going to be a swine to get off next time.
Tension wrench to 53 ft lbs YES.
If you have over tensioned the flywheel on, it is going to be a swine to get off next time.
/\ /\ /\ Butcher!
Torque specs are for good reasons, and should always be adhered to, nothing but greif can be obtained by overtightening a fastener.
Over tightening can cause breakages, warpage, component destruction, thread stripping, and thread stretching, which will cause the fastener to loosen under vibration.
Torque specs are for good reasons, and should always be adhered to, nothing but greif can be obtained by overtightening a fastener.
Over tightening can cause breakages, warpage, component destruction, thread stripping, and thread stretching, which will cause the fastener to loosen under vibration.
Last edited:
Not to mention the harmonic distortion to the crank assembly when using an impact.
Spend a few bucks on quality tools.
I use and ONLY use my SNAP-ON digital torque wrench and its varified for calibration regularly.
Every single fastener has a torque spec for a good damn reason the problems described and solved here are one of many examples why.
So the lesson for today kiddies is have a manual,read/use the manual,buy quality tools,correctly use these tools as well as using the right tool for the job.
Spend a few bucks on quality tools.
I use and ONLY use my SNAP-ON digital torque wrench and its varified for calibration regularly.
Every single fastener has a torque spec for a good damn reason the problems described and solved here are one of many examples why.
So the lesson for today kiddies is have a manual,read/use the manual,buy quality tools,correctly use these tools as well as using the right tool for the job.
Similar threads
