Rich,
I am going to bring up the V belt versus Serpentine belt argument again because I am right in the middle of it.
My former USAF Suburban with a 6.2 and all 12 volt system truck would eat a stock 60 amp 12SI alternator 1 to 2 times a year. Running the front and rear a/c blower motors on hi all the time just killed them. I bought a replacement from O'Reilly's with the warranty and kept my first core. I rebuilt the core and got to where I could swap in a replacement in less than 10 minutes, take the broken one to the store, get an exchanged new one and swap it in a few months later. I finally installed a CUCV 100 amp 27SI alternator with the different CUCV brackets and tried to let the truck idle a few minutes after start up and before shut down with no fans running. Almost a year now and the same used CUCV alternator is still alive. I have gone through 3 Gates belts for that alternator in the past year though.
With that in mind, my build for the Cowdog CUCV clone Suburban started with the idea of at least one 100 amp plus alternator. Looking through the Chevy diesel forums of which there are several. Lots of reading about things going bad but never a mention of failed 105 amp 130CS alternator or of serpentine belts going in just a few thousand miles. I wanted the CS130 alternator and serpentine belt drive.
I had an engine with the pre 1995 belt drive to pull parts from. I then got the 1997 engine with serpentine drive from NDT. Which style to choose? It matters because the older version has the single thermostat and the alternator on the drivers side of the engine. The 1997 up style has the alternator on the turbo side and dual thermostats with will make fabrication of throttle cable brackets and cruise control brackets and no room for the fast idle solenoid.
I already posted about how I for sure wanted the 130 gpm HO water pump. Some "experts" on some sites claim if you run the big pump with a single thermostat it will blow out the freeze plugs and that "GM put the dual thermostats on for a reason and you can trust them." I ordered the 130 gpm pump and got it in last week. It has a 1 inch fitting for the bypass hose to the thermostat housing. The GEP V belt engine had a little 3/4 inch fitting on the top of its water pump. Yet, when we pulled the pump. The impeller was just a 1/4 inch smaller than the 130 gpm pump. GEP has a pump of very similar flow, a smaller bypass tube and a single thermostat. Freeze plugs look ok to me as well. I feel it is very safe to run the big pump with just a single thermostat now.
I didn't know until this week that the V belt and serpentine belt pumps have their own totally different backing plates. I had read about different backing plates for the water pump but thought the difference was related to the size of the pump, not the direction the pump turned. So, a serpentine water pump has to have a serpentine backing plate. Same for the V belt pump to of course.
It is possible with a little bit of grinder work to run the dual thermostat cross over with the older serpentine belt set up and again, with a little bit of grinder work to run the single thermostat cross over with the newer set up. I thought because of the huge bypass hose outlet on the 130 gpm pump I was going to be forced to run the dual thermostat cross over. Nope, the single 1993 cross over has the same size hose end on it. Maybe all serpentine belt cross overs have the bigger hose? I don't know since I have only personally seen two. The GEP cross over bypass hose fitting matches the GEP pump outlet of 3/4".
That gets me to yes for serpentine belt system, yes to the 130 gpm water pump and yes for a single thermostat cross over. What about alternators? As mentioned above, the older serpentine set up put the alternator on the drivers side. Which means the a/c compressor will be next to the turbo. The newer set up is switched. But, the newer set up has the ready made brackets to add a second alternator on the drivers side of the a/c compressor. What to do?
My older belt set up had the brackets and a Sanden a/c compressor. I am adding rear a/c to the Cowdog and have pieced together all the lines from donor trucks to where just the end fitting at the compressor has to be changed if the compressor is on the passenger side. Very simple, cheap I hope and easy. Adding a few inches of wire to the alternator is super easy as well.
The 1997 set up is made for a GM HS6 compressor. They have a terrible reputation. Sanden makes a bolt in model for a few hundred dollars. However, then I have to get the a/c lines across or around the front of the engine. I really don't want a/c lines in the way of radiator work, fan work or checking the power steering fluid level. Plus, I doubt the longer lines will be cheap or easy.
That leaves me without an easy add on second alternator though. I am going to make the truck all 12 volts and just run one alternator. We will see how it goes. I will however keep a look out for the ambulance alternator kit and prep things to swap over to the newer set up if it is needed.
Having CUCV trucks to pull parts from and several V belt engines on hand. V belts are easier for a 12/24 system and would probably be easier for a straight 12 system too. Hopefully, I will know in a year or so if going serpentine was the correct choice for on the road/trail dependability and reliability.
