Re: engine assembly

Posted by Owen_Dyneto On 2014/11/20 23:11:35

Main bearing cap bolt tension 65-70 ft.-lbs. And they should be torqued AFTER the aluminum crankcase has been attached to the cast iron bores, never before.

Rod bearing cap bolt tension 45 ft-lbs if you stayed with original type poured babbitt bearings or used 1935-39 rods with OEM-type flanged insert bearings. If someone cut and modified you 1934 or earlier rods to accept some substitute insert bearing and made some accommodation to correct for the absence of thrust faces, I suggest you get a recommendation from them.

I would never use values given in tables for maximum permissible torque based on thread and bolt grade. It's all about clamping force and it's effect on surrounding components; engineers made torque recommendations to reach a specific clamping force compatible with such variables as distortion of components, expansion & contraction, etc. For example, excessive cylinder head torque will distort the engine block or at the least, place it under stress.