Cat 3116/3126/5.9 Cummins ???

B Gillespie · Jan 12, 2011

In a class 6/7 truck, what are the pros and cons of each? Looking at a few used bucket trucks, Cummins is on a Ford chassis with an Allison, 3116 is on a 90's Chevrolet chassis with an Allison, 3126 is on a 2001 Sterling chassis chassis with a 6 speed manual. Is the Sterling a rebadged Ford?

blacksheep10 · Jan 12, 2011

hard to find something bad about the cummins. I've heard of old 3116's having block and some head problems, valve seats falling out silly stuff like that. Apparently the later ones are pretty good. We have a c7 (the next in the 3100 line) and it pulls quite strong

Hotrod · Jan 12, 2011

1st off I'd see if the cummins is a 24vavle. No matter what it will be dependable, but you will be slack on power with either in stock form, especially the 12valve. I have had 2 of em with 12 vavles, and they were good trucks but slow. We have 3 trucks with the Cat engines in them. They are C7's, not sure what numbers that transfers to, but 2 are older trucks. They do alot better, and the strongest one is the Chevy 7500, 2001 model with an Allison, LOADED with tools and a crane. Just my 2 cents. :dblthumb:

Big Block tube buggy · Jan 12, 2011

C7 pulls good, have two in power company trucks, one is giving trouble starting in cold weather. Spent 6k on it at cat and it still is not fixed, it is in the shop now they say it has a heui fuel pump will not let engine have fuel till it gets oil pressure with starter. Other than that their ok.

COLT · Jan 12, 2011

From some of my prior posts on Hardline many of you know that I am a hardcore Cummins fan... In the case of the 24 valve motor in the Ford- I am not a fan... I have experience with a ford with the 24 valve in it (industrial version) and the owner has had a lot of problems. They have been through a few head gaskets and 1 high pressure pump. Like I said I AM a Cummins fan and own 2 dodge 3500's myself but have had bad luck with the lower HP industrial motor.. Part of the reason why I believe we had the problem was because the truck was doing a lot of interstate driving at 70-75 mph the motor was turning 2400 rpm minimum on cruise at speed. I would look for a Kodiak based truck with a Duramax in it if you plan on a lot of long range trips. If you are just staying around town the Cummins is what I would go with. The Cummins may pay for itself in low maintenance costs as well being as though the parts are easy and cheap to come by!!

wontwork · Jan 12, 2011

Go with the chevy. I have 2 of them with Cat motor. One has over 300,000 on it and has sat and run many days runnin the pto for air compressor or cran use. Only problem with it was the crank was replaced when almost new(factory defect) and had a fuel line mess up. It has a 5 speed with 2 speed rear. The second truck has on 32,000 on the ticker and has only been used to deliver some metal and set a few things with the crane. Its a 6 speed and reguires cdl's. Both are '93 model topkicks.

Pumpkin · Jan 12, 2011

Big Block tube buggy said:
C7 pulls good, have two in power company trucks, one is giving trouble starting in cold weather. Spent 6k on it at cat and it still is not fixed, it is in the shop now they say it has a heui fuel pump will not let engine have fuel till it gets oil pressure with starter. Other than that their ok.

If I'm not mistaken the oil pressure works the injectors. Its probably got a oil leak at one of the injectors. I know the LMTV/MTV we have at work will do this. But the 2 we have had would not start at all by the time we found them.

Big Block tube buggy · Jan 12, 2011

Thanks Pumpkin I will check on that, it cranked ok for 3 years then started giving problems. Cat said to change to thinner oil in cold weather.

Marty · Jan 12, 2011

Have a good buddy with GMC's with the 3126, He bought them brand new and they have been worked hard and been great engines. They pull pretty good but he did swap the 6 speeds for 9 speeds which make a world of difference here because its the mountains. I have a C13 in one of my trucks and it has 250k on it trouble free. I like CAT motors but they are more expensive to work on and rebild than a Cummins. I have a big Cam 4 cummins in one of my other trucks but I really like the CAT better. I know theres no comparsion to a 5.9, but I have no expierence with them

B Gillespie · Jan 13, 2011

Correction:
'92 Chevrolet 3116/Allison
'98 Ford 5.9/Allison
'99 Sterling 3126/6 spd.

Truck will see 90% city use with the occassional road trip to the next job or main office.

Willymutt · Jan 13, 2011

I would stay away from the 3116. We always called them throwaway engines because they were junk after awhile. The 5.9 isn't bad and the 3126 is a decent engine. What are the horsepower and torque ratings on them? The Sterling isn't a rebadged Ford. They have a lot of similarities to Ford. They were their own brand though.

DavidsCJ7 · Jan 13, 2011

I wish I had as much luck with my 3126 engines as you guys. We have about 10 in our fleet of 80 trucks. They easily account for 75% of our engine repair cost. They are constantly in the shop for injectors, huey pumps, high pressure lines leaking, supply pumps, and the front covers have a tendency to crack. We had to put our 3126 engines on a 30 day PM schedule just to help alleviate some of the issues. Any longer than that and the problems magnify. Its a regular occurrence for us to go out and check the oil and there is none in the engine, its all in the fuel tank.

I've often said if someone gave me a fleet of trucks with 3126 engines in them and all I had to pay for were the maintenance and repairs, I would turn down the offer.

redline diesel · Jan 13, 2011

Our bucket trucks and small cranes are fl70 with 8.3 cummins and love them...have had 3116 and 3126 cats hate them and the junk chevrolet chassic...have dt-466 manuel pump love them got rid of the 466e...love 5.9 in a dodge,but not in a med duty truck....we have a diesel shop also,so we work on them to.the fl70 8.3 is a good powerfull motor,we slide the fuel plates on the 12 valves and get around 10 mpg