Primary drive gear walking sideways!

[trickedcarbine]

The max torque on the crank nut should be 80% (or whatever safety factor you like) of what the yield on the threads of the crank are. Chances are the nut will be the weaker between the two.

Hence the nut Stripping and the snout being fine

 

Dave I didn't quite mean there is a sequence for the nut it self, but that it is more precise to use proper spec on every nut and bolt on these things. So for cases, cyls and the head he reccomended to use step torquing in sequence. For the clutch components he reccomended using the desired values from the clymer manual.

[okbeast]

The desired sequences from the manual for torquing the nut down should have never allowed it to strip threads or come loose. If it was done correctly, then something weird happened.

[trickedcarbine]

The desired sequences from the manual for torquing the nut down should have never allowed it to strip threads or come loose. If it was done correctly, then something weird happened.

Bulge in the convex washer was out ward and I took it to 47 or 48 ft lbs whatever the manual says on that chart. Either way it's going back together with straight cut gears. I even went so far as to permatex the key way so I know I was detailed.

Guess shit happens, but I am glad if it was torsional force from repeated launching that it blew the nut off and didn't eat a bearing.

[trickedcarbine]

Update, took the nut to a metalurgist at a place in Farmington michigan called RTI laboratories and have found out that the cryotreatment of that nut might have been part of the issue. I brought him another nut as well that was un treated and he stated that after a couple quick tests the stock un treated nut seemed to show better tensile properties where the Cryo treated nut that failed though seemed to be a bit harder in the Rockwell scale, yet it was seemingly brittle. They do a lot of testing and much of it for Roush and the big 3 and I believe I saw a few Detroit diesel parts in there.

 

I dunno if that is the total cause, but in his 20+ years of experience opinion.... He says many parts can benefit the Cryo, but it is not something he would ever do for high rpm fasteners that see sudden bursts of stress.

I also think that the bearing being locked in with 2 clips also takes some of the torsional flex out of the equation meaning that gear was thrusting a touch more on the nut then normal.

 

Note to self...... No more cryotreatment of fasteners!