Torque Spec Guidelines

[30 Ply 30U]

info transfer from old board.

Torque Spec Guidelines
I recently rebuilt my 29 Plymouth 4 cylinder from the block up.  I used some general guidelines provided by Tom Hannaford (Antique Auto Cellar) and compared them with the guidelines from Tom for the early 6's and used the lower of the two for each specific bolt.  Even with that, I managed to strip a flywheel to crankshaft bolt.  I have learned to be a little on the conservative side with torques on these older engines.

For example, for the Plymouth 4 cylinder (28-31) Head bolts Tom Hannaford recommends 60-65 ft-lbs.  I used 55 ft-lbs (Based on the below lower numbers and 7/16 head bolts)

As a general rule, Tom Hannaford recommends for Antiques:

3/8"   25-30 ft-lbs
7/16" 50-55 ft-lbs
1/2"   80-85 ft-lbs
9/16"  110-120 ft-lbs
5/8"  140-150 ft-lbs

One exception - for my 29's 3/8" rod bolts, I used 40 ft-lbs, a compromise between the torque listed for the 1935 (45-50 ft-lbs) and Tom's general guidelines (25-30 Ft-lbs, which seemed a little too low to me).