Re: 4.0 questions

[farna@xxxxxxx]

I think pre 87 serpentine belt cranks are the same length in front as V-belt cranks. Would have to check to be sure, but I know the balancer is different between the pre 87 and 4.0L. The belt on the 4.0L is at least 1/4" closer to the block, due mainly to the balancer being "backwards" in comparison to the earlier 258 serp setup. There is a 1/4" flat space IN FRONT of the belt teeth on the 4.0L, BEHIND the belt teeth (between timing cover and belt) on the early 258. The 87-89 258 uses the same belt setup and balancer as the 4.0L, and shorter crank snout.

On July 7, 2005 andrew hay wrote:

> there are pluses and minuses for any of the different 258 cranks.  a
> serp belt one [used as early as '82] is easiest; v-belt snouts are
> about 3/8" [~10mm] longer and need trimming or a spacer.  a '72-'80
> 12-weight crank is supposed to be smoother, especially for low-rpm
> running, and stronger - but nobody on the strokers group has reported
> any problems with the '81-up 4-weight crank.
> 
> 258 main caps are beefier than the 4.0's, but you'd need to align bore
> the block to use them and for a moderate stroker not really necessary.
> 
> '96-up 4.0s have a main girdle which mounts on studs sticking out from
> the main bolts.  it's a drop-in for any 4.0 but you need a few washers
> under the girdle to clear a 258 crank.
> ________________________________________________________________________
> Andrew Hay                                  the genius nature
> internet rambler                            is to see what all have seen
> 
> adh@xxxxxxxxxxxxxxxxx                       and think what none thought


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