This is a FWIW, since I'm not sure what sort of interest it may have.

Anyway, I put my new digital torque wrench on the crank of the 452 yesterday after doing the final "torque + angle" routine on the rod bolts and found the turning torque of the assembly "as is" (light lube on the piston assemblies and bearing lube on the crank & rod journals) measured 17-18#s.

I've read somewhere that a typical street build is 25-30#s and "real" race engines can be down closer to (or in the?) single-digits, so I think this looks fairly low-friction for a street/strip build. I've never actually checked this before on my own engines, so I don't have any point of comparison, unfortunately.

Just finished a 408 sm blk build using 1/16" rings and I came up with a torque reading of 25 ft lbs. Bearing clearances were a little on the tight side. Piston to wall clearance was .008". ( forged "Icon" blower pistons).

That's a good number for rotating torque. What was the breakaway torque reading?

mine 19

My last one - 16#.

my 408 is 20#

Will that number be any different once the rings are seated?

I usually shoot for under 20 on a steel rod motor with 1/16 compression rings. 16-18 is pretty typical. Aluminum rod motors in my experience seem to have a bit more initial drag. You can tell a lot about the motor just by setting the crank and torquing the mains. Line hones are HP.

Drives me nuts when guys insist on main studs and then want to skimp on a hone.

The cylinder wall finish, the ring width and tension and the lube used will affect the breakaway and rotational torque. Dick Landy told me years ago to use 20 to 23 lbs break away and 16 to 18 lbs. rotational as a way of measureing a good job I have a SB Chevy pump gas blower motor with 5/64, 5/64 compression rings and 3/16 standard tension oil rings in the shop now, that rascal is not as easy to turn as the bigger bore Mopar motors with 1/16,1/16, 3/16 oil ring with standard tension I did a bracket race motor last year that had 1.5MM,1.5MM,compression rings and 3MM oil ring, it was real easy to turn, I should have checked it and written it down It was noticably easier to assemble and turn over My next race motor may have thinner rings than that

u should use a beam type torque wrench to check turning torque

hi, a beam torque wrench will give you truer results. as for rotational torque, my 340, 5# to rotate, metric rings in motor.

Quote:

---

Will that number be any different once the rings are seated?

---

Yes, it will be smaller to varying degrees depending on cylinder wall finish.