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1970 GMC New Look Transit Bus Modification

03-28-2017, 11:37 AM
Hi. I am a newbie looking for some information and on which forum topic to ask this question. I hope this may be of some interest to someone out there and can point me in the right direction.
I bought a 1970 GMC New Look Transit Bus at an auction at a heck of a price. The engine has been rebuilt and I want to refurbish it as a food truck.
I wish to use the engine as my generator, it is a Allison 6V71 238HP?
Is it my correct understanding that I would need to put in a more robust alternator and this should be able to give me the power that I need? I am looking for generator power in the 10,000 to 12,000 W range.
I have experience in food trucks, but not so much in Detroit Diesel engines.
I would be very much grateful for any information that someone might give me.
Thank you for your time.

03-29-2017, 08:08 AM
Are you looking for 10-12 kW of 12VDC or of 120VAC? Is the alternator you're referring to the one that maintains the bus charging system or the one for the food truck accessories? How many batteries does the bus hold currently?


03-30-2017, 06:53 AM
It would be AC. All my equipment is AC. The bus currently has 2 batteries used for staying the bus up. Standard car batteries.

03-30-2017, 06:54 AM
Batteries are for the bus charging system. I need to generate power for the kitchen equipment.

03-30-2017, 08:09 AM
Does the bus then already have an alternator for providing 120VAC, along with some PTO to decouple the driveline from the engine in order to run the 120VAC alternator? If so, you should be able to replace the current alternator and replace it with the 12kV alternator, assuming you have the space to install it.

If you have an RV service center in your area, that might be a good place to check out for some of the supplies needed.


03-30-2017, 11:32 PM
It has what I would consider just a standard bus alternator of the time. My research has indicated that the expense of buying the proper alternator, or an inverter, or using a PTO generator considering it's a 2 stroke engine and that running it idle will cause either a massive waste of motor oil or deisel usage, or both. I think my best option is to find a purpose built generator and try to muffle the sound and vent out the exhaust and use it in board or attached to the body of the bus somehow. (Which would be a huge eyesore).

Blue Bowtie
04-22-2017, 08:46 AM
I was recently involved in the setup of a pipeline inspection truck. The truck was a Ford F550 chassis-cab and the cargo cube housed a control room and camera operation room. The power cable reels, winch, and camera equipment along with the control room and video equipment were all 120VAC. The truck had an on-board Onan generator which used the same diesel supply as the truck. It was remarkably quiet and had a two-stage muffler, rubber isolation, remote pushbutton start on the desk, and completely enclosed. I wish I would have noted the model number, but it was something like this:


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