Packard Forum Index » Pre-War (1899-1942)

I am getting ready to assembly the engine for my 1934 1101-718 320 cu in. I need the torque spec. and torque sequence for assembly. Does anyone know where I can get this information?

Lonny, it's not clear if you're asking about the cylinder head, rod and main bearing caps, or something else. But the answer is the same, in that era there were no torque specs and mechanics were trained to do by feel. Torque specs came later but can be retroactively applied to earlier cars.

Cylinder head fasteners should be clean and dry and torqued in 3 stages to about 63 ft-lbs. Start in the center and spiral out across and front to back. You'll have to use guesswork on the stud between the coils.

I'll check on bearing caps and post later.

Lonny,on the cylinder head, don't forget to check the torque again after about 15 minutes of running, again after a couple of hours, and yet again after a season of use.

Google torque spec for bolt sizes. There is a general rule for torque specs for ANY bolt or stud based on bolt size. Look in just about any Motors Manual or Chiltons etc. They usually give such a chart for torque ratings based on bolt size.EXACT torque is not critical but rather EVEN torque of all the bolts is most critical.

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.