ALTERNATOR  UPGRADE KIT, ADDITIONAL INFO  
R. Kwas 11/2000

Special Applications

Mounting an o.e. Bosch alternator using the swem bracket.  This situation has occurred twice - first, when the threaded mounting boss of a B20 block broke off (?), the bracket saved the day because it is secured to the block by the three threaded holes which were used on B18 block castings to mount the generator bracket, and fortunately were retained on B20 castings (although unused); and second , when a new Bosch alternator and (mechanical) regulator were already on hand, and didn't need to be purchased.  Since no mods to bracket were necessary in this case, the option still remains for a future upgrade to a higher output D-R alt. with internal solid state regulator.

The following mechanical differences between D-R and Bosch alternators exist:

1.  The Mounting boss nominal length of the alt. castings.  Bosch is shorter.  See Pictures 1 and 2.  Solution:  Use a spacer (or a stack of washers), sized to take up remaining space, but this spacer must be sized after cutting (Bosch) casting to correct for belt plane offset - See highlight on pic No.1 - once bolt is torqued, everything is locked from movement.
 
2.  The Pivot bolt sizes.  Bosch used a larger bolt than upgrade kit, so pivot hole in casting is larger.  When using smaller bolt from upgrade kit, this could cause misalignment.  See Picture 3.  Solution:  Use metal tubing or strategically sized and formed piece of sheetmetal to center pivot bolt in larger hole of Bosch alt., again, once bolt is torqued, everything is locked from movement.

3.  Belt Plane.  Different offset of alt cases.  Solution:  To make offset equal to that of D-R alt., and assure pulley alignment, cut away 3/8" of casting as highlighted in Picture 1.
   

Picture 1, Delco-Remy Alt. on left, Bosch on right.  Offset in mounting boss of Bosch casting which causes pulley misalignment is highlighted.

Picture 2,  Showing mounting differences from another angle (Bosch alt. on top).   Pivot boss length differences are visible.

Picture 3,  Showing mounting differences in castings and pivot bolt holes.

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