proper gears on 24 volt alt ?

[johnjem]

hey guys i cked history not much said on the gears for the alternator<i know the book says to replace,bu to what? ok here it is   old 8v71 blown engine  24 volts has 55 teeth in the motor for alt,new 8v71 also has 55 teeth in the motor for the alt,witch was a 12 volt,now the alt i am putting in the new 8v71 24 volt has 20 teeth and the alt i took out the 12 voltwitch i am not using has 24 teeth  i am usuming thet as long as the teeth in the motor are a match all is good or do i have to swap out the 24 teeth and go with the 20 teeth <break down>
old 8v71=55teeth
new 8v71=55 teeth
12 volt alt=24 teeth
24 volt alt =20teeth
i need the 24 volt alt to go into the new 8v71   i hope i explained it good enough??let me no  ps i am bringing it to a shop who rebuilds them just to go thru it and have them swap gears if it needs it let me now what u think thanks john   1970 gmc 4905

[captain ron]

You have to use the same gear that it came with originally on the bus or it will make a God awful noise. Use the 55.  Don't ask me how I know

[chris4905]

Captain Ron is right on......use the teeth ring that is matched to the gear on the alternator.  Don't change gears and rings.  (hope that makes sense).

I removed my 8V71 and replaced it with a 6V92 (on an 4905).  The alternator was bad on the 92, so..........I used the alternator off the 8V71 and also removed it's ring from the 8V71.  Then put the 8V71 alternator and ring on the 6V92.

Geeeezzzzz........this thread sounds like we're all talking in circles.

It is easy to remove the alternator ring from the engine block.  It's held in place by about 8 allen bolts.  Should fit right into the opening held by the old alternator ring.

DO NOT mix alternator gears and ring gears !!!!

Good luck,
Chris Christensen

[johnjem]

thanks guys i still confused going in circles  ,both engines have 55 teeth rings the alts have differnt rings  the 24 volt has 20 teeth and the 12 volt has 24 teeth  witch do i use 20 teeth or 24 teeth i think they will both fit since they both came out of 55 teeth??

[johnjem]

is that 6 allen bolts or eight on the engine ring?

[captain ron]

1 gear should be smaller than the other both will go in but you should use the bigger one as the teeth will mesh properly. the smaller one wil make loud grinding noise.

[johnjem]

thanks ron thats what i will do keep all gears together so good to me thanks