CUCV Serpentine Conversion

87cr250r

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For the back story, I daily drove a CUCV for about 5 years and put close to 100k miles on it. Overall, the truck was very reliable, except for the v-belts. They required replacement with a specific brand of belts every 20k miles and getting the power steering pump tight was a PITA. I have always wanted to do a serpentine belt conversion to improve reliability.

Finally getting close to completion. The 96+ accessory brackets are actually designed for dual alternators and available on eBay. The bracket for the idler pulley is unobtanium but can be fabricated from 1/4 plate with a few washers.

The CS130D alternators are not able to be built as isolated ground, the rectifier doesn't allow it. I opted to isolate the alternator by drilling out the mounting holes to 9/16 and using some 1/2 air brake tube and fiberglass washers to insulate. A CS144 alternator could fit the bracket and the rectifier would be much easier to convert to isolated ground. I was originally planning to run a 24v single alternator with a 50 amp dc-dc converter to run the 12v systems. I could not find a 24V option. The CS144 can use the 19SI stator which is available in 24v, but you'll still need to figure out a rotor and voltage regulator.

Yes, the black alternator is coated in PlatiDip as the case is live to the 12v +. I plan to form a cover from ABS plastic or fiberglass in the future.

If you can get the 96+ timing cover it has a 4 pulse per rev mag pickup which is perfect for driving a tach (that's the wire hanging off the front).

If you want to have AC you'll need to use the dual thermostat housing and make some modifications. The dual housing does not clear the mechanical IP. This setup should work with the original radiator hose.
 

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Rutjes

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Nice setup. Why is the vacuum pump still there? Is it because of the center mount turbo? If possible I would convert the waste-gate actuator to a mechanical one and get rid of the vacuum pump. Most of the 6.5 TD guys get rid of it because the pump is a known point of failure. They say a 1 inch shorter belt should fit, but that was not the case for me. I tried multiple lengths. The belts stretched quickly. I ended up raising the A/C compressor with washers to re-tighten the belt once the stretching settled on the tightest belt I was able to put on.

You can use a 96+ upper radiator hose to make the dual thermostat housing work. You only need to modify or fabricate a throttle cable bracket.

IMG-20210524-WA0051.jpeg IMG-20210524-WA0053.jpeg 39d61c3c-7563-4376-bbf9-dbe70784aba8.jpg

2004 CR125R and 2007 CR85R owner here by the way. (y)
 
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87cr250r

Well-known member
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Location
Rodeo, Ca
I kept the vacuum pump for the TH400 transmission shift modulator. I do intend to use a mechanical waste gate. I tried getting a GM7 unit but they're only available in large quantities.

It appears you converted yours to 12V and ditched the dual alternators?

I am intrigued by the throttle cable bracket. Which I had thought of that before chopping up my outlet.
 

Rutjes

Well-known member
Steel Soldiers Supporter
358
270
63
Location
Amersfoort, The Netherlands
I kept the vacuum pump for the TH400 transmission shift modulator. I do intend to use a mechanical waste gate. I tried getting a GM7 unit but they're only available in large quantities.

It appears you converted yours to 12V and ditched the dual alternators?

I am intrigued by the throttle cable bracket. Which I had thought of that before chopping up my outlet.
Yes we converted to 12V. However, I have experimented with dual alternators. Designed the bracket and had it laser cut. I think I posted the file somewhere on here. If you want it I can e-mail the file.

IMG_20201116_142600(1).jpg

Some Googling will get you multiple examples of modified throttle cable brackets. Most do it when doing a DS4 to DB2 swap on later (GMT400) 6.5 trucks. 96 and up I think. I didn't like those and decided to fabricate a bracket of my own.
 
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87cr250r

Well-known member
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548
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Location
Rodeo, Ca
Hmm, it never occurred to me to Google DS4 to DB2 conversion. I only searched 6.2 serpentine conversion. I'm going to commit to my 180 elbow for now, see how it goes. Those aluminum 90's weren't cheap. I found a fast idle solenoid that has the adjustment on the pump side so it doesn't stick out through the solenoid. I was able to clear everything on the DB2 pump.

I did get the bracket cut already. I'm much more handy with dividers, jigsaw, and drill than I am the aluminum stick welder. It took a couple of tries to get the idler in the right position. Apparently there are two different diameter idler pullies so keep that in mind. The C3500 has a larger diameter pulley. That worked out better for me because it basically forced the horizontal position of the pulley so the belt would clear the bolts.
 
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