[6pack] Piston rings --> torque for turning crank

[Cregg Cowan]

Hi Lou & Berry,

I was also curious about how hard the crank should be to turn as I'm 
building up the engine.
I just measured that 21 ft-lbs of torque are required to turn my newly 
rebuilt bottom end (Grant rings with King HD rod & main bearings).
Up to 24 ft-lbs is OK according to p. 30 of Vizard's book, but I'm not 
completely sure if that is for just the crank and pistons.

I measured this by hanging a 15 pound weight on my breaker bar 
handle.  When suspended at 14" from the center of the crank the crank did 
not turn; at 15" the crank turned (15 lbs * 1.25 ft = 18.75 ft-lbs).  I 
estimate the 18" breaker bar weighs 3 pounds (probably more like 2 pounds, 
but I'm being conservative), so the unloaded breaker bar contributes 2.25 
ft-lbs of torque (3 lbs * 0.75 ft) for a total of 21.

For this measurement the rear oil seal was installed, as was the timing 
chain and cam (but no lifters, oil pump, or timing chain tensioner).

Let me know if this is not clear and I can send photos of the test setup.

Hope this helps,
Cregg

At 05:56 PM 3/1/2009, lfm614 at aol.com wrote:
>Thanks Berry,
>
>Got the bevel and its up but they are not marked top so I was double 
>checking.  Got these from TRF too.
>
>Did you redo your bearings as well?  If so, how hard is it to turn the 
>crank with the new rings and new bearings?
>
>Lou