Crank Bolt Torque on PSI spline?

Just switched to psi spline on our A/Fuel motor, just looking for a recommended torque on the 3/4-16 bolt, seeing as it's 4.5" long, not 2" like the old dual key cranks, that we have always torqued to 440 ft/lbs.
Grade 8 or L9 bolt sufficient? or do I spend $64 on the RCD one?
Thanks,
Clif

 

Clif,
I recently switched and kept my tourque at 400 lbs (Grade 9 bolt). Only have 8 runs on it, but no issues so far.
Marty

 

I agree with Will - but I wish that RCD would publish a correct torque on their splined hub long bolt.....we have been torquing to around 250 (limit on our Snap-On 1/2" drive torque wrench) on RCD splined hub without any issues...with the keyed crankshafts we cranked it down to 375...

Since the splines are now taking the twisting load I believe that you could reduce the torque but I kinda hesitate to go much less than 250 without supporting instructions from RCD or PSI...

 

You still need clamping force. I have been running splined hubs for about 4 Yrs. and found out they can come loose easier than the keyed hub at times --375 with L-9 from Ottoman with his washer and now is just what it should be.

 

Thanks for all the responses fellas!
there is only about.780 of threads available to clamp on to....hate for it to come loose!
Still use never-seize on the bolt, or oil/peanut butter?

 

I bought 1/2" longer bolts that my keyed cranks use so I had more than enough engagement.

 

We switched from keyed cranks to RCD spline. The bolts are about $130. Are the RCD bolts necessary or will a grade 8 bolt be sufficient

 

Give automan a call and get his bolt and washer very reasonable

 

Will do. Thanks