I wonder where he got that torque figure? I just looked at several charts for graded fasteners, and for bare (unplated and un lubricated) the torque for Grade 5 is about 475lbs/ft. For plated and lubricated bolts the torque is more like 350. For Grade 2 it's about half that, and for grade 8 about 40% more. Bolts all have rolled thread which are generally stronger than the machined threads as found on the crankshaft. So to come up with a suitable torque for a 7/8" machined thread in an unspecified steel would be a non S swag, IMO. Perhaps Phil was able to determine the type and hardness of the crankshaft and extrapolated from there?
The thickness of the nut may or may not have an impact on the torque figure. I was taught you need at least 1 diameter (of the male thread) of thread engagement to achieve full strength in a bolted joint, with 1.5 diameters preferred in order to provide a margin of safety. So if the 'thin' nut is roughly 7/8" tall then there is little to be gained by a deeper nut.
Sorry for the delayed comment - I haven't been on here for a bit. Figures from here will give a rough guide
https://www.norbar.com/Portals/0/downloads/TorqueValueGuide.pdf one should read the notes at the top of the page and realise that torque wrench settings are very much dependant on surface finish of the thread - plating - lubrication - washers and a lot of other things which can be controlled in a production line environment but not when we are doing a one off installation in a small workshop. I have made assumptions in the absence of information from manufacturers. I assume the material to have an ultimate tensile strength round about 50 tons / sq in (S grade) and you can see the reading recommended for 7/8 UNF S grade threads is 433 Lbf ft.
The reason for getting this right is that the assembly forms a compound bar to withstand the sideways thrust of the centa rollers - something the original crankshaft was not designed for.
I don't recall telling anyone to discard the flat washer - you should discard the spring /star washer - there is no point in locking the nut to a flat washer which is not locked to the shaft.
Hope this helps folks to understand what is going on inside that bell housing - feel free to contact me if you want further clarification of my ramblings.
Phil
