Fan Belt - Again

[Mulletwagon]

Was using a NAPA 25-20426 cogged belt - worked great. Put on a cast aluminum two-blade fan - and the belt is now too short. The pulley on the fan is slightly narrower than the previous unit and the belt rides slightly higher which precludes slipping the belt over the alternator - even with the holding bolt removed. The question is how does the 25-20426 belt compare with a BX40 belt (outer circumference) ? Will a BX 40 work or should I consider a BX41 or BX42 ? Hope to avoid multiple trips to the local parts pirate.

[CarlG]

I would try the BX40, and if that's still too tight, move up to the BX41. Doesn't solve the multiple trips to the store, but sometimes that's the only way to make it happen.

[eagle]

If you happen to have an old belt around, cut it and put it on the pulleys. Measure the gap. bingo, you have your length.

[canadian]

if you are using the small alternator pulley, the BX4O is perfect , any other BX numbers will be to long and won't be able to be adjusted.

[Mulletwagon]

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Originally Posted by Mulletwagon

Was using a NAPA 25-20426 cogged belt - worked great. Put on a cast aluminum two-blade fan - and the belt is now too short. The pulley on the fan is slightly narrower than the previous unit and the belt rides slightly higher which precludes slipping the belt over the alternator - even with the holding bolt removed. The question is how does the 25-20426 belt compare with a BX40 belt (outer circumference) ? Will a BX 40 work or should I consider a BX41 or BX42 ? Hope to avoid multiple trips to the local parts pirate.

And the answer is ---- BX41. The belt fit perfectly. It slipped in between the pump shaft snout/fan and radiator and positioned over the alternator pulley easily with the alternator pushed full inboard. When tightened the locking bolt was right in the middle of the travel slot of the tensioning arm. The BX41 is one inch longer than a BX40 and one inch shorter than a BX42.