I-6/250 with CS alternator ? - The 1947 - Present Chevrolet & GMC Truck Message Board Network

88Ironduke · 04-08-2014, 09:06 AM

So I have a nice CS alternator that had the right price tag, free. Its a pretty chrome unit but alas all things come with a price of some sort.

My question to the inline six gurus is about the mounting of the alternator. My truck did not have its original externally regulated alternator in place when I brought this home. But with the original single groove water pump pulley it was clear that the new CS style alternator does not line up with the groove on my stock water pump pulley. Did the inline 6's ever come with a lower alt mount that pushes the alternator further forward on the block?

I have a installed what I think to be a SBC water pump pulley for illustration purposes. The inner/aft groove lines up nice on the alternator and drive pulley on the crank. The outer/forward groove is where I should be at in a perfect world. Technically a guy could easily make this work, but its a smaller diameter pulley which would in turn drive the water pump fast than stock....

My fear is the coolant would be moving too fast and possibly cause an over heat condition due to coolant not having enough saturation time to pick up heat in the block. Or it would cause premature water pump failure.

Penny for your thoughts....
88Ironduke

TheSeeker · 04-08-2014, 03:17 PM

I beleive that the alternator mounts in front of the bracket, bolt through the back. It appears that your pulley alignment is a tad off in this picture, but if you mount the alternator with the tab in front of the bracket, it might even out?

68gmsee · 04-08-2014, 04:20 PM

It's always a pain trying to line up accessories on these old trucks but I doubt you will have any heating/cooling problems using the inner pulley. The thermostat should be able to control the water/engine temp.

If it is a serious worry, try to locate one with same size pulleys.

88Ironduke · 04-08-2014, 04:38 PM

Thanks guys. I tried moving the top bracket around and it seemed to drop in the best at its current position. However I will adjust/shim accordingly. My hope was to find a guru that may have done this swap on a 250 or even 292. Its still early yet.

88

TheSeeker · 04-08-2014, 05:21 PM

I just installed a 12SI alternator type on my 250, and am having alingment issues as well. I had to shim the alternator forward to make it line up on the inner groove.

04-08-2014, 09:06 AM	#1
88Ironduke Registered User Join Date: Jul 2010 Location: Willingboro, NJ Posts: 489	I-6/250 with CS alternator ? So I have a nice CS alternator that had the right price tag, free. Its a pretty chrome unit but alas all things come with a price of some sort. My question to the inline six gurus is about the mounting of the alternator. My truck did not have its original externally regulated alternator in place when I brought this home. But with the original single groove water pump pulley it was clear that the new CS style alternator does not line up with the groove on my stock water pump pulley. Did the inline 6's ever come with a lower alt mount that pushes the alternator further forward on the block? I have a installed what I think to be a SBC water pump pulley for illustration purposes. The inner/aft groove lines up nice on the alternator and drive pulley on the crank. The outer/forward groove is where I should be at in a perfect world. Technically a guy could easily make this work, but its a smaller diameter pulley which would in turn drive the water pump fast than stock.... My fear is the coolant would be moving too fast and possibly cause an over heat condition due to coolant not having enough saturation time to pick up heat in the block. Or it would cause premature water pump failure. Penny for your thoughts.... 88Ironduke __________________ Retired USAF - No rockets, no mortars, no bad guys shooting...No stress!!! My Build Thread: Project 72' Green http://67-72chevytrucks.com/vboard/s...d.php?t=587932

04-08-2014, 03:17 PM	#2
TheSeeker Registered User Join Date: Dec 2009 Location: Glendale, AZ Posts: 337	Re: I-6/250 with CS alternator ? I beleive that the alternator mounts in front of the bracket, bolt through the back. It appears that your pulley alignment is a tad off in this picture, but if you mount the alternator with the tab in front of the bracket, it might even out?

04-08-2014, 04:20 PM	#3
68gmsee Active Member Join Date: Jul 2007 Location: Centrally located between Houston, Austin and Waco. BCS area. Posts: 7,947	Re: I-6/250 with CS alternator ? It's always a pain trying to line up accessories on these old trucks but I doubt you will have any heating/cooling problems using the inner pulley. The thermostat should be able to control the water/engine temp. If it is a serious worry, try to locate one with same size pulleys. __________________ 68 GMC 250/3 speed Saginaw p/b p/s 69 Chevy 350/350 currently in pieces still lookin for a cab 06 Trailblazer I just want a vehicle that I can work on, that won't talk to me, leave error msgs or keep track of how I drive...

04-08-2014, 04:38 PM	#4
88Ironduke Registered User Join Date: Jul 2010 Location: Willingboro, NJ Posts: 489	Re: I-6/250 with CS alternator ? Thanks guys. I tried moving the top bracket around and it seemed to drop in the best at its current position. However I will adjust/shim accordingly. My hope was to find a guru that may have done this swap on a 250 or even 292. Its still early yet. 88 __________________ Retired USAF - No rockets, no mortars, no bad guys shooting...No stress!!! My Build Thread: Project 72' Green http://67-72chevytrucks.com/vboard/s...d.php?t=587932

04-08-2014, 05:21 PM	#5
TheSeeker Registered User Join Date: Dec 2009 Location: Glendale, AZ Posts: 337	Re: I-6/250 with CS alternator ? I just installed a 12SI alternator type on my 250, and am having alingment issues as well. I had to shim the alternator forward to make it line up on the inner groove.



Register or Log In To remove these advertisements.

Register or Log In To remove these advertisements.