Re: Flywheel Bolt

Re: Flywheel Bolt - OOOPS

Posted by Bill Wilson on March 01, 1998 at 11:30:51

In Reply to: Re: Flywheel Bolt - OOOPS
posted by Marco Tahtaras on March 01, 1998 at 00:18:04

I broke one of the same bolts as I was replacing the ones I had taken out, but got very lucky in getting it out. It was a bad bolt, by the way. Fortunatly, I had taken several engines apart at the same time, so I had extra bolts, and I did torque them to 80 lbs.The length of these bolts is critical, since if they are too long, they will hit the rear seal.: Tony,
: The bolt length was initially 27/64" long. With the intro of the single disk clutch the length was reduced to 13/16" for both the new assemblies as well as servicing the multiple disk assemblies. The bolt head was drilled for safety wire and no lock washer was used. To bottom out, I believe it would have to reach the bearing flange of the block which would prove to be a serious problem.
: 80lb torque seems excessive for a 7/16"-20 bolt. I don't specifically know, but would expect about 60lb.
: If you are mounting the flywheel that hasn't been balanced on the crankshaft with orientation marked, I strongly recommend that you check the flywheel for runout and wobble with a dial indicator. The original limit is .005" on both limits. Once a machinist has done his stuff, they are usually better one way than the other (rotating 180 deg.). Make sure there are absolutely no burrs, etc. between the mounting surfaces. If they were balanced together then just install as marked.
: Also a good time to check the flange of the flywheel housing similarly. It should be true with the rotation of the crankshaft or flywheel within .006". It was intended for two brass or copper shims be installed at the upper bolts to match the thickness of the gasket at the lower bolts. But you would be amazed what adding one or removing one of the shims will do to shift the housing. And after all, clutch chatter is no o o fu u un!
: Good luck,
: Marco
: ---------------
: : I am putting together my drive trane and was putting in the 4 flywheel bolts to the crank. I read in a manual that they should be torqued down to 80 foot lbs. When i was tightening one bolt, it broke.
: : Is 80 foot lbs too much or was my bolt weak, it was the one I took out.
: : I also measured the length of the bolts, 3 seem to be replacements and one seemed orginal. The original was 3/4 and the new ones were 1/8 longer and it seemed to bottomed out.
: : I think they were too long. Is there a washer or lock-washer that is needed?
: : Any help will be appreciated, I plan to put it together tomorrow.
: : Thank,
: : Tony

E-Mail Comment to Webmaster