CAt vs Cummins for my next rig - diesel pusher

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joester

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I thought I'd post a new question I have after talking to my mechanic.
without posting what he told me, I thought I'd ask owners of each and what they have experienced.
I'm looking for a short (32-34) diesel pusher, and so far really like the Holiday Rambler Neptune pbd,which is basically the same as the Monaco Cayman.
I believe these come with the Cummins ISB 300 hp engine.
what are your experiences with these rigs and more particularly this engine.
thanks so much.
any info on rigs with a similar CAT engine would be great help to me - and what makes use the CAT engines?
 

Tom

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Like Chet, I wouldn't hesitate to have either one. We have a Cummins in our coach and a pair of big CATs in our boat. We have forum members with both makes in their respective motorhome and I don't recall hearing or reading any dissatisfaction with either one.

We had an issue when both CATs broke turbo studs while we were at sea, but we were able to get home safely and CAT went out of their way to take care of the repair and cover collateral damage.

A friend and forum member recently had to be towed when his new coach with an ISX Cummins engine broke down one day out of the factory and the nearest Cummins dealer/tech couldn't fix it. But the problem was resolved promptly by Cummins once they were towed to a knowledgeable facility.
 

BernieD

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Joe

I have had both a CAT and a Cummins engines in my 2 coaches. Both were/are fine engines. I do question the ISB engine in a full sized Class A coach. Everyone that I know that has that engine in a coach has been disappointed. Major problem is low torque, about 600#/ft IIRC.
 

Tom

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BernieD said:
I do question the ISB engine in a full sized Class A coach.

Bernie, I was about to do the same, but realized he's talking about a "short" (32-34 foot) coach. It would be good to know the weight of that coach.
 

Smoky

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I have a Cummins 330 in my coach and I have been very pleased with it.

Originally, when I first started shopping for a coach i only looked at those with Caterpillar.  All my life I had admired Caterpillar equipment and thought it was the premier diesel.

But then I became attracted to Newmar motorcoaches.  I was disappointed that the current Newmar offering in the 2005 year was all Cummins.  I did some research and the more i researched the more I liked what I saw.  We had our first visit to a Cummins shop in Bakersfiled California and were VERY impressed with them.
 

Jackliz

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joester said:
I thought I'd post a new question I have after talking to my mechanic.
without posting what he told me, I thought I'd ask owners of each and what they have experienced.
I'm looking for a short (32-34) diesel pusher, and so far really like the Holiday Rambler Neptune pbd,which is basically the same as the Monaco Cayman.
I believe these come with the Cummins ISB 300 hp engine.
what are your experiences with these rigs and more particularly this engine.
thanks so much.

Detroit first, then a Cummins.

Jack and Liz
Blue Bird Wanderlodge with 500 HP Detroit Diesel, 8V92

 

blueblood

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BernieD said:
Joe

I have had both a CAT and a Cummins engines in my 2 coaches. Both were/are fine engines. I do question the ISB engine in a full sized Class A coach. Everyone that I know that has that engine in a coach has been disappointed. Major problem is low torque, about 600#/ft IIRC.

Bernie _ I and a lot of my friends had the ISB275/300 in FW Discovery at ~24,000 GVW and liked them very much. We got close to 10-11 MPG and could clear mountains at 35-45 MPH. In fact a close friend of mine has a trailer with his Corvette in it and has had good performance across US and up to Alaska. Torque is a contant 660 ft lbs across the entire operating RPM so it gives better performance than some engines with advertised higher peak torques at RPM that are not in operating range.
 

BernieD

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blueblood said:
Bernie _ I and a lot of my friends had the ISB275/300 in FW Discovery at ~24,000 GVW and liked them very much. We got close to 10-11 MPG and could clear mountains at 35-45 MPH. In fact a close friend of mine has a trailer with his Corvette in it and has had good performance across US and up to Alaska. Torque is a contant 660 ft lbs across the entire operating RPM so it gives better performance than some engines with advertised higher peak torques at RPM that are not in operating range.

Leo

I am glad that you are having good results with your ISB. My comments were based on friends that have/had coaches with the ISB engine.
 

joester

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thanks for all the replies.
my mechanic mentioned that he had not worked on the most recent Cummins engines, but the earlier (pre-2003) engines he had worked on were not made as well as the CAT's he had worked on. I'll pass on the info on the Cummins you have shared, and ask him to ask around with other mechanics as to the newer engines.
I did notice the torque on the Cummins is about 660, whereas the CAT 350 hp says that it has 860 - 200 ft/lbs of torque seems to be a big difference.
the Holiday and Monaco I like are about 25k lbs empty - probably 32k lbs loaded - is the 300 hp with 660 ft'lbs torque enough for me to climb thru the rockies with no trouble?
what about with a car or trailer in tow?
I appreciate the help - when I do finally make the step up, we will be keeping it for quite a while, so I want to be sure to ask all the questions now.
thanks for all your input.
 

CurtRR

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Different size engines, but I noticed that Country Coach, in their new Tribute 260, charge extra for a 400 hp. Cummins over a 400 hp. Cat.
 

BernieD

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CurtRR said:
Different size engines, but I noticed that Country Coach, in their new Tribute 260, charge extra for a 400 hp. Cummins over a 400 hp. Cat.

The Cummins ISL 400 has 1200 #/ft of torque, I believe the CAT only has 1050. Also, the ISL 400 probably includes an engine compression brake (similar to but with a different name and design as the Jake Brake), while the CAT probably includes an exhaust brake. The exhaust brake works well but not as well as the engine brake.
 

Tom

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Bernie,

CAT has an option for the Jake brake, but I don't know which engines do/don't have the option and it may not be offered as an option on some coaches with CAT engines.

The CAT engines in our boat have provision for Jake brakes, but they wouldn't do much for slowing the boat down  ;D
 

BernieD

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Tom said:
CAT has an option for the Jake brake, but I don't know which engines do/don't have the option and it may not be offered as an option on some coaches with CAT engines.

Tom

True there is an option but unless the coach builder decides to order his chassis from the chassis builder with that option when he places his oriiginal order and specs, it will be either very expensive or very long delivery time or both.
 

joester

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resurrecting this thread I started a while back - still considering the plusses/minuses for each of these -
say compare a 300-325 ISB Cummins with a 325 CAT - years 2005-2007.
any further input for me? I still like the 32pbd Cayman/Neptunes, but am more open now to a 34'.
I've added the Fleetwood Expedition to my list of potential rigs - saw a 2005 34h I like - I believe it has the 325 CAT. I like the 3 slides so much more than the 2 - the living area gets so much bigger when open.
 

BernieD

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joester said:
resurrecting this thread I started a while back - still considering the plusses/minuses for each of these -
say compare a 300-325 ISB Cummins with a 325 CAT - years 2005-2007.

Both are excellent, fairly bullet proof engines. Not sure about the specs for those years, but generally, the CAT torque figure was significantly higher than that of the ISB. With a choice of the two, I'd take the CAT.
 

Ron

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Based on the way Cummins reacted t the problem on some of their ISL engines of installing an idiot light warning that the engine is about to come apart I vote for the Cat.  We do have a Cummins but I sure wouldn't buy another from a company that  installs an idiot light instead of ficing a manufacturing defect. JMHO.
 

joester

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have not looked THAT close on the Fleetwood Expedition to see where radiator location is - but really like the floorplan with the 3 slides - the living area opens up nicely.
as to the Cummins, not sure if the ISL is that similar to the ISB that are in the  32pbd Cayman/Neptune I like so much.
I can see where torque difference would make a difference, but in a 32pbd - wouldn't 660# be sufficient?
I'm still not so sure I want to go 34', but like I said, the floorplan and the CAT make the newer fleetwood 34h a nice rig to consider.
thanks for the input.
 

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