The case bolts are like thick rubber bands that stretch a long way when  tightened. The object is to stretch them just into their working range when  torquing them up. Once torqued they hold that clamping power for a few months,  then they relax just a hint. So to find a bolt that is still at full torque a  year or a half a year later is almost impossible.

You discover that the bolts seem to be very tight if you attempt to add  torque. Not the case (pun). The torque load has stuck the bolt at the head  contact surface and the thread contact area. There is a word for this factor,  but I forgot it. So the proper procedure is to unscrew the bolt a full turn. The  idea that the torque is to be done with "Dry" threads is a bit hopeful. Some  lubrication was there from running, less than perfect cleaning or just touching  the threaded end with your hands. So the torque on each bolt is actually  different to start with.

So, if you want to see what the torque was approximately, mark a corner of  the bolt head with a dot. Mark the case next to that dot. Unscrew the bolt a  full turn with a breaker bar. Not a torque wrench.

Set the (Clicker style) torque wrench to the torque you expect to  find.
Mark the socket right over the corner of the case bolt with the dot. In one smooth motion with no stops, crank the mark on the socket around  until the mark on the iron lines up. You may find the click before that so just  stop at the click. Or, you may not find a click so you just keep turning until  the click. You may find that all of the bolts need to turn a bit further to pull  the same torque. Or all of them stop before the marks line up. I use Nickel anti seize on the threads and under the heads and torque to  the smaller of the torque range numbers. I torque the case bolts 6 times on the  day of the build, then again the next day. I always find a few  unhappy bolts the next day. You may loose a bolt now and then doing it my  way, so keep a few spares on hand.

If you are turning a bolt and it is not gaining torque, stop turning it a  discard it.   Whatever method you use, do the torque pattern 6 times. You will be  surprised how many bolts keep turning as the stack settles down to dead flat. The irons are just not all that stiff. If it is holding torque the stack  will keep a warped iron flat enough to run. So the engine may finish the race with all the irons junk and warped to junk status. So a leak from a warped iron  is less likely. Will retorquing the stack stop the leak? Maybe....................

Lynn E. Hanover



message dated 8/17/2012 11:41:22 A.M. Eastern Daylight Time,  echristley@att.net writes:

I have a  very slow oil leak, and I think I've traced it to originating at the joint  between the rear rotor housing and
rear side plate.  I'd rather not  open the engine up to apply sealant, but it is half a day's work to  disassemble
everything down to the point I can get a torque wrench on the  case bolts.  I'm conflicted on if I should go ahead and
break the case  open if I'm down that far already.

How likely is that the seeping oil  can be solved by re-torquing the case bolts?  If the torque is correct,  is it likely
that the end plate is warped?

Would a good plan be to  check the torque, and only continue disassembly if there is no movement?   That is assume that if
it is torque properly it must be a warped plate or  missing sealant, but if the torque is low bringing it up to spec will
solve  the leak.


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