cummins 350 big cam safe rpm

Up to 2400 will work successfully, they have been taken higher but cooling fan speeds become excessive and plastic fans blow apart and wreak havoc.

If you're running a Formula series engine upping the rpms that much will quickly take it out of it's max torque range. They are setup to run 1800-1900 rpm for torque and economy.

 

It won't get hurt that easy unless you try to run it above 2500 rpm for sustained periods. A 350 governed at 1900 rpm is a formula engine tuned for fleet economy. Cummins also built a 2100 rpm 350 engine so if you like a little more rev room on top you could very safely set it to 2100 or even 2150 like the older model NTC 350's were governed and you will never come close to hurting it.

 

As stated earlier, a Formula 350 is set for 1900, factory setting for a nonFormula motor is 2150. Mine is set at 2350 and will run that all day. I've seen them set to run 2600 or higher, but they won't run that for extended periods of time. Cruising rpm for the old NTCs, including the Big Cams is 1700 to 2150. Those with Jakes work best at 2000 to 2150 on the Jake.

 

Your right Autocar,when the NTC were popular and running strong pretty much every one had them governed at 2400, and they would run like that forever, but when they came out with the big cam series they didn't need the rpm, they lowered the torque rise, so the rpms started going down from there, but it was because they kept bettering the torque rise, not because the high rpm hurt the engine, the lower the rpm, the better the fuel mileage for the most part, and longer longevity of the engine overall.

 

I am looking at buying a 1985 Freightliner with one of these motors in it, is it a good motor? I am used to newer motors, that is why I am asking.

 

there a good motor in there time they dont comapare the the electric motor why would you want one an if the gov has its way they will outlaw them soon

 

the gov is not going to outlaw them. too many of these trucks are still on the road in the Midwest running farm work, flatbeds, end dumps, hoppers. they are also more reliable than a lot of these newer emission trucks. i currently run an 04 kw with a c15 cat and am in the process of dealing with a guy to get an early 80s pete 359 exhd and will be putting it to work.

 

Umm because there a heck of a lot better then what's out there today rookie and you can easily get 600 horsepower out of them best motor ever produced is the mechanical cummins.