Re: [Amc-list] sending so I don't forget (diesel MJ)

[adh@xxxxxxxxxxxxxxxxx (Sandwich Maker)]

" From: "Swygert, Francis G MSgt 436 CES/CECM" <Francis.Swygert3@xxxxxxxxxxxx>
" 
" From: andrew hay <adh@xxxxxxxxxxxxxxxxx>
" 
" " From: "Swygert, Francis G MSgt 436 CES/CECM"
" <Francis.Swygert3@xxxxxxxxxxxx>
" "
" " The .55 OD gear is probably NOT a good idea!! The engine wouldn't be
" " turning enough rpm to build any power, so 6th gear would be near
" useless
" " unless going down hill. With a diesel it might be better, but even
" they
" " need to turn a minimum rpm to produce power! Automotive diesels aren't
" " like the big stationary types that produce gobs of power at 1500-2000
" " rpm -- with a redline of about 2200!
" 
" true enough - but what if you [he] are running deep axle gears, like
" 4.10s or lower?
" 
" -------------------------
" 
" A good point, but then the 3.52:1 first gear is useless! First gear
" reduction would be a really deep 14.43:1. I surveyed AMC cars from
" around 65 to 83 and discovered that a good rule of thumb is to have
" first and final gear ratios add up to about 6.5 (between 6 and 7) for a
" manual transmission. Anything more than 7 is too low and anything less
" than 6 is too high. For example, if running a 2.53 rear axle you need
" about a 4:1 first gear for good take-off. So find a trans with a 3.5-4.5
" first gear. Automatic transmissions can get by with a lot less gear due
" to the torque multiplication of the converter -- a good range is 5-6 for
" an auto trans. Larger engines generally use gears closer to the lower
" number, smaller ones the higher number. Weight of the vehicle has the
" same effect -- heavier vehicles to the larger end of the scale. 

jeeps violate this rule.  okay, they use taller tires - 215/75r15 is
about the smallest - but the tj/xj/yj 4-cylinders run 3.93:1 1st and
4.10:1 axles.  even the 4.0 runs 3.83:1 with a 3.07 axle.  and the 4.0
auto with a 2.8:1 1st has a 3.54 axle.  compared to these, a 3.52 1st
isn't very odd.

i've been looking into toyota l-series diesel engine swaps.
surprisingly, the little diesels run pretty low gears, 4.30ish - pretty
much the same as their gas counterparts.  this is with transmissions
like the jeep ones above.
________________________________________________________________________
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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