Posted by Charlie on Saturday, January 06, 2001 at 10:23AM :
In Reply to: M-37's and trannies: posted by Chris Lube Lublin on Saturday, January 06, 2001 at 3:24AM :
It's pretty straightforward of the bellhousing (bh) is out of the vehicle: stick it up to the transmission and see if everything matches. If not:
1) Do the 4 mounting holes on the trans match up to thick metal on the bh. ?
2) If the center hole is bigger than the input bearing retainer, have an annular "adapter ring" made with precisely the correct dimensions. Actually, if the ID of the ring is 0.001" too small it can be installed by heating it up to about 250-300F. and then it will stay snug. Then the index diameters will be matching.
If the center hole is too small, have it milled out.
3) Then, when the bh fits properly on the trans, have the 4 mounting holes drilled and tapped
4) The tip of the input shaft and pilot bushing must match. The length of the input shaft must allow an absolute minimum of 0.50" of the pilot tip riding inside the bushing.
5) The splines on the input shaft must match the clutch disk selected,
6) The diameter of the input bearing retainer snout must match the throwout bearing.
7) The clutch throwout mechanism must work properly without the TO bearing falling off the snout, and the snout must not touch the clutch diaphragm fingers. These rise out towards the snout when the pressure plate bolts are tightened down!
8) If you can't get the 4 trans mounting holes to match up to good thick metal on the bh and/or if they interefere with a mechanism like the clutch throwout linkage, you can theoretically drill from the inside of the bh and drill and tap holes inside the front of the transmission case. The bolts must not interfere with the gears in the front of the trans!!!! They must be short if the would otherwise hit the gears!!! They must be sealed with some reliable sealer!!! In other words, this should avaoided unless absolutely necessary. This sort of thing would normally be necessary with one or at the most 2 bolts (the lower ones) mainly if the lower pair mate up below the bottom of the bh, unless the pattern is much too wide on top.
9) An alternative to the above IF the input shaft is longer than necessary: make a ~1" aluminum adapter plate with the 4 bh holes countersunk and attached with Allen head fasteners, the plate being drilled and tapped for the 4 mounting ears. Proper center indexing is critical, the machine work must include a circular ridge in front to index in the bh hole and a circular hole (all concentric!!!) to match the bh bearing retainer. It's better the 1st way.
If the trans is 5th direct you need 4.89s. 5.83 final gearing with a 318 is ridiculous unless you are planning 44s. Even with 44s 4.89 gives you 2350 rpm @ 60, just right. with the 5th direct version you have a nice close 4th gear for hills and passing.
With 5th overdrive, I'd still consider 4.89s unless your tires will be 39" or taller. Certainly if highway use is planned and fuel economy is desired.
I have a 540 overdrive myself, it's behind a Perkins diesel first in a Landcruiser and now soon in my Carryall; owned it since '75. Finding the proper gears for a Chelsea 350 (reversible) PTO was NOT easy. The OD version ratios are, if you don't know:6.06, 3.31, 1.81, 1.00, 0.821, reverse = 6.06.
In 1975 when I acquired it it was a real "find" and although it's an old now obsolete design it was 20 years ahead of its' time considering the popularity and desirability (if you believe the 4WD magazines!) of the NV4500 in conversions.
Charlie
|
Follow Ups:
This board is powered by the Mr. Fong Device from Cyberarmy.com |