cummins or cat

[ron55]

Thanks, I really appreciate all the replys. I torn between a ford, Dp or fifth wheel with a DuroMax. I have put more into my workwhore than most Dp cost to manitain. I thought it would run forever and had it Painted, Big tv, Convection MW, washer/dryer, travler satellite, track bar, Barzal EMC programming, Kon Shocks, Henderson track bar and full size Kitchen Aid Drawer dishwasher plus rest easy sofa completely rebulit along with the dinett booth it is now my home most of the time and I may just park it in Florida

[cmpncrsaider]

Hey Maverick BBD
That looks like a beautiful rig you got there!
Would the Cat 350 be comprable to my 350 cummins?
And how does it handle the Rockies pulling toad?

[RVNeophytes2]

Originally Posted by RJay

Regarding the overheating problem, I think it's the result of improper or lack of maintenance and not the fault of the engine manufacturers. An initial proper and thorough cleaning of the radiator and every six months after, or immediately after driving on salted roads, will prevent any overheating problems as a result of insufficient cooling.

I was looking at this thread in reference to a 425hp Cummins I'm thinking of buying, and need to weigh in, reference Cat C7 overheating.

My own rig is meticulously maintained; the entire cooling system has been gone through by professionals and serviced with premium coolant. Further, I've both cleaned (degreased, compresor etching, fine-mist pressure washed) both portions of the radiator. Then, I conducted an airflow check of every square inch of the radiator surface.

Earlier, I'd trimmed the baffling around the radiator to near perfect tolerance and sealed every gap in the radiator shroud with expanding foam.

Nonetheless, on steep grades with an ambient temperature above 90F I will get an overheat of 220-225F; recovery is swift when speed is reduced.

In short, overheating can indeed occur with some systems performing at their peak with perfect maintenance.

[Mr_D]

Originally Posted by cmpncrsaider

Hey Maverick BBD
That looks like a beautiful rig you got there!
Would the Cat 350 be comprable to my 350 cummins?
And how does it handle the Rockies pulling toad?

CAT C-7 has 860 ft lbs torque, the Cummins ISC 350 has 1050 ft lbs, unless you have a Banks, then it's 1200 with a MUCH broader HP/torque curve than even the ISL 400

[Chuck 1935]

Originally Posted by RVNeophytes2

I was looking at this thread in reference to a 425hp Cummins I'm thinking of buying, and need to weigh in, reference Cat C7 overheating.

My own rig is meticulously maintained; the entire cooling system has been gone through by professionals and serviced with premium coolant. Further, I've both cleaned (degreased, compresor etching, fine-mist pressure washed) both portions of the radiator. Then, I conducted an airflow check of every square inch of the radiator surface.

Earlier, I'd trimmed the baffling around the radiator to near perfect tolerance and sealed every gap in the radiator shroud with expanding foam.

Nonetheless, on steep grades with an ambient temperature above 90F I will get an overheat of 220-225F; recovery is swift when speed is reduced.

In short, overheating can indeed occur with some systems performing at their peak with perfect maintenance.

When the overheating occurs do you gear down and keep the RPM's up around 2000 ?

[Luckiest Dreamer]

I retired from driving 18 wheelers after a million miles or so! Most of it was sitting above a Cummins. Since we had a service department I didn't care what was there unless I broke down along side the highway and had to sit there when the temp outside was 20 below! We used Cats, we used Detroits! They all would break down occasionally. Usually the problems had something to do with the fuel or air! Seldom, was I able to blame it on who built the thing!
My MH now has a Mercedes. That is distributed by Detriot! I get it serviced at Freightliner. After the million + miles I have driven I can't quite make up my mind on which one is the best!

[RVNeophytes2]

Originally Posted by ron55

I have read on here how great DPs so I was hell bent to get me one untill I read the cummins and cat forums, all I see is overheating and 20mph up the big mountains in the Rockys.

Today, I was climbing at 6,000 feet at 60 mph, driving my C7 Caterpillar powered Excursion, pulling a 5,000 lb load.

A gasser had closed on me and hovered alongside, as we approached the hill. He was clearly intent upon passing; but, as we started up the grade he fell back. The divergence was so dramatic, I literally lost sight of him.

I've been running with DPs this entire trip, we've all be climbing moderate grades at altitudes between 5,000 and 10,000 feet; nearly always those rigs stay above 55mph.

Yes, there are lots of variables. But, events in real life, totally arbitrary and random, suspect the torque inherent to DPs ranks them above most gassers, in the hills (particularly at higher altitudes). Plus, I don't recall ever hearing of a Cat or Cummins blowing at 15,000 miles (or 150,000 for that matter).

[BCooke]

Am I missing something or where is the general weight comparison between the gas and diesel units. My understanding was that once a unit got over a certain weight you had to go with a diesel. If that is correct would that not mean that even if a gas buggy were to catch you he may be up to 1/2 as heavy as a DP?
I only have a 36' TH but my understanding is some of those DP are around 45k. For me that sounds heavy on a 5, 6, 7 percent grades at altitude.

[RustyJC]

Originally Posted by RVNeophytes2

I've been running with DPs this entire trip, we've all be climbing moderate grades at altitudes between 5,000 and 10,000 feet; nearly always those rigs stay above 55mph.

Naturally aspirated gasoline (or, for that matter, any) engines lose 3-4% (depending on manufacturer derate) of their rated power for every 1000 ft increase in altitude due to decreasing air density. A turbocharged diesel, however, typically can carry full sea level power rating all the way up to as much as 10,000 ft elevation (some manufacturers/models will begin altitude deration at lower elevations due to turbocharger sizing and turbocharger speed limitation issues.) That's a significant turbodiesel advantage at higher elevations.

Rusty

[Dadeaux]

I have crossed virtually every mountain range in the U.S. in my 330 Cat and have had no issues with speed, power, heat or brakes. My unit is equipped with a one-stage exhaust brake for decending mountains and it works very well. I recently had my brakes inspected and have had very little pad wear in 50,000 miles.

My unit weighs approximately 34.000 lbs loaded and I pull an Acadia that weighs in at 5,000 plus.

[cmpncrsaider]

I'm glad to hear you're pulling that acadia through the mountains with no trouble. I plan on flat towing my 4dr pickup weight about 4900 lbs.. MH has a 350 cummings, and I too use my exhaust brake alot, as well as the tranny automically downshifting.

[Dadeaux]

Originally Posted by cmpncrsaider

I'm glad to hear you're pulling that acadia through the mountains with no trouble. I plan on flat towing my 4dr pickup weight about 4900 lbs.. MH has a 350 cummings, and I too use my exhaust brake alot, as well as the tranny automically downshifting.

Last year I was camped beside a guy pulling a long cab Ford F250 Diesel FWD. He said he could hardly tell it was back there, BTW he had the Cat 330 engine.

[RVNeophytes2]

Originally Posted by Chuck 1935

When the overheating occurs do you gear down and keep the RPM's up around 2000 ?

No, I haven't but I'll sure give it a try. Will let you know if it's successful.

Thanks, Chuck.

[Chuck 1935]

Originally Posted by RVNeophytes2

No, I haven't but I'll sure give it a try. Will let you know if it's successful.

Thanks, Chuck.

Your welcome, The engine is governed to not exceed 2,400 RPM's so you will be OK up to there. Good luck !!

[RJay]

Originally Posted by RJay

Regarding the overheating problem, I think it's the result of improper or lack of maintenance and not the fault of the engine manufacturers. An initial proper and thorough cleaning of the radiator and every six months after, or immediately after driving on salted roads, will prevent any overheating problems as a result of insufficient cooling.

Originally Posted by RVNeophytes2

I was looking at this thread in reference to a 425hp Cummins I'm thinking of buying, and need to weigh in, reference Cat C7 overheating.

My own rig is meticulously maintained; the entire cooling system has been gone through by professionals and serviced with premium coolant. Further, I've both cleaned (degreased, compresor etching, fine-mist pressure washed) both portions of the radiator. Then, I conducted an airflow check of every square inch of the radiator surface.

Earlier, I'd trimmed the baffling around the radiator to near perfect tolerance and sealed every gap in the radiator shroud with expanding foam.

Nonetheless, on steep grades with an ambient temperature above 90F I will get an overheat of 220-225F; recovery is swift when speed is reduced.

In short, overheating can indeed occur with some systems performing at their peak with perfect maintenance.

As I look back at the posts I think I was responding to smlranger's post about the dirty radiator but my response does seem a little over reaching. I agree with you that cooling problems can be the result of a crimped or collapsed hose, sticking or partially closed thermostat any number of things besides a dirty radiator.

A friend of mine wanted to show me how well he was able to get his side radiator clean. When I looked at the engine side of the radiator it was immaculate but the fins were completely worn away, probably by road salt deposits, exposing just the channels making the radiator much less efficient at getting rid of heat.

[Mr_D]

Originally Posted by RVNeophytes2

Plus, I don't recall ever hearing of a Cat or Cummins blowing at 15,000 miles (or 150,000 for that matter).

You must have missed out on the wrist pin problems in the ISL's then. Most blew by 15,000 miles. Cummins covered them under warranty though, but still there have been problems.
Then there's the porous blocks on the ISB's Casting 51 or 59 as I remember.
Then there's the pulley lube problems on the CAT 3126.
PS I have a Cummins ISC, had a CAT 3126 before that, both have been absolutely flawless.

[Mr_D]

Originally Posted by Batman_777

CAT has more torque (initial power) and Cummins has better mpg for similar sized blocks.

I posted this a page back or so but it seems to have been missed.

In order for the Allison trans to last they limit the torque output of the ISC's and ISL's in first and second gear. That may be where the "Cat is faster off the line" came from.

[Cat]

Theres more to a DP than just engines, ride,handling,less noise,braking. Not losing power in the mountains as mentioned is a benefit. And DP can haul alot more weight at the same mpg as a smaller lighter gasser.Cummins is a good engine as are Cats.