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Cummins PT270 questions?


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I know they had much higher torque than other engines of similar hp in it's day, except the Maxidyne. I've seen numbers somewhere in the 900-1000 lb range which is right there with an NTC-350 of the same era. If you're familiar with Brockway's Huskidrive, that's the engine they used to compete with the Maxidyne. They put in in front of a 5 speed with a 2 speeed (5.05/3.70) rear axle and instructed you to use low speed on the rear and flip a switch for high speed when in 5th. That says something of it's capabilities. I've seen them quite a bit in vocational trucks in front of Fuller 8ll's and 7 speed Spicers.

When my Dad used to haul bananas, another company from the bronx had a PT-270 and a 13 spd Roadranger in a Diamond Reo. He would have no problem keeping up with us in a K100 with an NTC-350. We had similar loads, both grossing in the low 70's on the NY Thruway between Albany and NYC. This is my only perspective having never driven a truck with one myself.

I had always thought that PT was an abbreviation for Power Torque, but have seen that argued on other forums.

Jim

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'Twas Cummins attempt at building a Maxidyne, but didn't work quite as well. UPS had thousands of them in GMC Astros, they kinda worked but made you wish for a genuine Maxidyne.

I'm guessing that wasn't Cummins' intention when they marketed it.

What tranny did the Astro's have. I read an article in one of the trucking rags, possibly Fleet Owner, where they did a report on a then new UPS Astro. It was similar to an Overdrive dissection report, but the focus was on the modifactions that were done to factory trucks to bring them up to UPS standards. All I remember was the emphasis on noise control and that the engine had been derated to 255 hp. I'm pretty sure it was a Cummins.

Jim

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I've got a PT270 in my '69 RL739LST,it has a 6 speed Spicer.I too was told by a Cummins man that they were built to compete with the Maxidyne.

Do you have a photo of it? I have never seen one, how do they differ from a 290 as far as looks?

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Is this the same engine referred to as a "Fleet 270"? If so I know where a very good running one in a wrecked truck resides with a Fuller behind it. Non turbo engine but 855 cubic inches.

Rob

Dog.jpg.487f03da076af0150d2376dbd16843ed.jpgPlodding along with no job nor practical application for my existence, but still trying to fix what's broke.

 

 

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i think they were 927 cid. oil pressure shouldnt be any different that any other cummins.

gg2

We the unwilling, Lead by the unqualified, are doing the impossible, for the ungrateful.

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i think they were 927 cid. oil pressure shouldnt be any different that any other cummins.

gg2

Of course I can't find anything on Google, but I believe the PT270 used the standard 855 block and the tweaks in the torque curve came from the fuel pump. The Super 250 used the 927 in block, not sure where else it was used.

Is this the same engine referred to as a "Fleet 270"? If so I know where a very good running one in a wrecked truck resides with a Fuller behind it. Non turbo engine but 855 cubic inches.

Rob

Fleet 270 came out some time later, when high torque rise engines were more common. Maybe the same motor with a new name?

Jim

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PT270 was an 855, basicly an Formula 300 with a flattened torque curve and 2100 RPM governor setting. Fleet engines were like a Formula, except governed to 1600 RPM IIRC.

Didn't the PT270 come out before the Formula's, or were you just using the 300 as a comparison? The Diamond Reo I mentioned above was a '71 but I hadn't heard of the Formula engines until the mid-70's.

Jim

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I've never been around Cummins engine but remember the advertisements in magazines about the "Formula" engines in 1981 and on. I remember JB Hunt had a lot of "Formula 230" engines.

Rob

Dog.jpg.487f03da076af0150d2376dbd16843ed.jpgPlodding along with no job nor practical application for my existence, but still trying to fix what's broke.

 

 

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Formula engines came out in the mid 70s. The engine in the '71 was probably an NHCT-CT, a 248 HP high torque rise version of the NHCT 270.

The door tag said PT-270, but I could be mistaken on the year.

Jim

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Formula engines came out in the mid 70s. The engine in the '71 was probably an NHCT-CT, a 248 HP high torque rise version of the NHCT 270.

I have a 1970 Transtar 4070 that has an NHCT-CT 270, it has a 9 speed roadranger. they came in 3 horsepower ratings (240, 255, 270. Ron
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That's probably just a plain NHCT. The NHCT-CT (Custom Torque) had peak power around 1700 versus 2100 for the plain NHCT and peak torque down around 1200 or 1300 RPM. Same engine, different tuning. The NHCT-CT came out around 1966 in response to the Maxidyne and was replaced by the "Formula" derived PT (Power Torque) engines in the mid 1970s.

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  • 2 weeks later...

PT270 was an 855, basicly an Formula 300 with a flattened torque curve and 2100 RPM governor setting. Fleet engines were like a Formula, except governed to 1600 RPM IIRC.

This is right

glenn akers

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That's probably just a plain NHCT. The NHCT-CT (Custom Torque) had peak power around 1700 versus 2100 for the plain NHCT and peak torque down around 1200 or 1300 RPM. Same engine, different tuning. The NHCT-CT came out around 1966 in response to the Maxidyne and was replaced by the "Formula" derived PT (Power Torque) engines in the mid 1970s.

right

glenn akers

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  • 8 years later...

Been so long I can't remember oil pressures or anything like that, but ran a PT270 in a 1978 International S-Line tandem dump truck for many years.

I do remember it pulled good for what it was. All the other dump trucks I worked with at that time had small International or Cat 3208 engines and that 270 was a powerhouse compared to them. But it was heavy. Get that truck into soft sand with it's wide base steers and the rear end was hopping where the other little motors would keep going.

Other thing I remember about it, was a lot of people had a really hard time driving it, but I was used to it. The throttle would really "float" in it.

You let off to shift and the RPM would float before it came down.

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