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I picked up a Delco-Remy 33si alternator, Cummins p/n 3400698, to replace the OEM alternator on my M818. My existing alternator was not failing, but I wanted to be ahead of that game. I have also followed some installs on both M809 and M939-series trucks with the NHC250. I liked the results. Special thanks to member Brutacus as his install was my model to follow.
https://www.steelsoldiers.com/threads/alternator-over-voltage.191655/ Starting at Post #7.
I ordered a second engine block alternator bracket that is supplied on the M809-series trucks, p/n11644677. For front to back adjustment, I had the block mounting holes slotted 3/4" forward. The 33si alternator has 1/2" mounting holes, so the corresponding holes on the bracket were drilled accordingly.
For proper fitting of the shorter mounting wings in the longer OEM bracket, I used:
For the adjusting bracket, I used a Spartan Alternator Adjustment Rod Bolt, p/n 0101-AA3-029. One hole on the mounting block is 3/8" and the alternator upper mounting wing is 1/2"-13 threaded hole. So, I drilled the 3/8" hole out to 1/2"
The slotted engine block mounting bracket attaches the same as the original except now you have some lateral movement to align the fan hub and alternator pulleys.
I used for bracket attachment:
https://www.steelsoldiers.com/threads/alternator-over-voltage.191655/ Starting at Post #7.
I ordered a second engine block alternator bracket that is supplied on the M809-series trucks, p/n11644677. For front to back adjustment, I had the block mounting holes slotted 3/4" forward. The 33si alternator has 1/2" mounting holes, so the corresponding holes on the bracket were drilled accordingly.
For proper fitting of the shorter mounting wings in the longer OEM bracket, I used:
- Front mounting: One 1/2"-13 X 2 1/2" Gr. 8 bolt, three Gr. 8 1/2" washers, one 1/2"-13 Gr. 8 locknut
- Rear mounting: One 1/2"-13 X 4 1/2" Gr. 8 bolt, four Gr. 8 1/2" washers, one 2" long unthreaded steel spacer, one 1/2"-13 Gr. 8 locknut
For the adjusting bracket, I used a Spartan Alternator Adjustment Rod Bolt, p/n 0101-AA3-029. One hole on the mounting block is 3/8" and the alternator upper mounting wing is 1/2"-13 threaded hole. So, I drilled the 3/8" hole out to 1/2"
The slotted engine block mounting bracket attaches the same as the original except now you have some lateral movement to align the fan hub and alternator pulleys.
I used for bracket attachment:
- four 3/8"-16 x 1 1/8" Gr. 8 bolts
- four Gr. 8 3/8" lock washers
- two Gr. 8 flat washers (in conjunction with the lower radiator hose support/guard)
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