The "school me on Renix alternators" thread.

[jpnjim]

Looks like there are two case sizes for replacement renix alternators:

130mm (5 1/8 in.) Diameter Case

121mm (4 3/4 in.) Diameter Case

 

 

Small case alts seem to be the 61a versions,

large case either 85a, or 100a.

 

Questions,

were both sizes original equipment on Renix 4.0L's?

is there a specific mount bracket for the 130mm vs 121mm, or will either alternator fit either mount?

 

 

Simple questions, I know,

but the last time I bought a new Renix alternator, they were an on the shelf item for a 5-6 year old vehicle.

 

Now they are special order parts for 20 year old dinosaurs,

and I don't want to order the wrong one. :doh:

[Pete M]

when I ordered my highoutput alt, they needed to know which case I had. there are at least 2 different styles and the mounting is different between to 2.

[1987Comanche]

The small case alternator is for non A/C trucks not equipped with HD cooling. The large case alternator is for all others. The larger alternator is a direct bolt-in replacement for the non A/C (non HD cooling) alternator though I did have to pry the U bracket open just a bit wider (1/4" or so) to fit it in.

As a bonus the bigger case/higher output alternators are cheaper than the small case ones :clapping:

Not only was it an upgrade but it was cheaper. How cool is that :)

[mvusse]

My truck does not have AC, nor did it have "heavy duty cooling", and it had the larger one. Then again, don't know if it was original.

[Pete M]

I vaguely remember being told that the bolt hole positions were different on 2 of the styles.

[jpnjim]

Thanks guys!

 

Keep the info coming if anyone has anything else to add.

 

I'll order the bigger one, and figure I may have to tweak the mount a bit,

I'm just hoping they still come with the pulley.

[Fezzik]

I don't know anything about the difference in alt. sizes, but when I replaced mine on my non-ac non-e-fan truck I got the 110 (I think, the highest one available) amp and it fit in no problem