Diesel engine step-up

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tmac

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Jul 29, 2006
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Hi,

We're looking at a 34-ft Monaco Knight with a 260 hp diesel. The owner says that the engine can be stepped-up to 300.

What do we need to know, or learn, about this? How to tell if the 260 is underpowered? Advisability and/or advantage to stepping-up? How much does this cost and what's involved?

thanks, 

tom
 

blueblood

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tmac said:
Hi,

We're looking at a 34-ft Monaco Knight with a 260 hp diesel. The owner says that the engine can be stepped-up to 300.

What do we need to know, or learn, about this? How to tell if the 260 is underpowered? Advisability and/or advantage to stepping-up? How much does this cost and what's involved?

thanks,?

tom

If your talking about a Cummins ISB 260 it can NOT be spgraded to 300 HP.
 

BernieD

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tmac said:
Hi,

We're looking at a 34-ft Monaco Knight with a 260 hp diesel. The owner says that the engine can be stepped-up to 300.

What do we need to know, or learn, about this? How to tell if the 260 is underpowered? Advisability and/or advantage to stepping-up? How much does this cost and what's involved?

Tom

One rule of thumb is 100 pounds weight per horsepower, so the 260 engine should be able to handle total weight of up to 26,000#s, maybe kind of slow climbing, but you'll make the top.

A concern about increasing horsepower in an engine is the cooling system and transmission. They MUST be able to handle the extra heat and load the increased HP will create. I'd be very careful about any HP change.
 

Tom

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Bernie is right on. Increasing HP, usually done with a chip upgrade, requires the cooling system to be capable of handling the additional heat/load. I suggest you contact either Cummins or Monaco tech support. Cummins will let you know if the engine can be up'd and Monaco will tell you if the cooling system can handle it.
 

tmac

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Thanks a lot for the input. We have decided to pass on this bus for the time being - for other reasons. The possibility of an upgrade might have been a dealer selling point instead of a plan for the future. Will be sure and follow your suggestions if we come back to it.

Tom
 

blueblood

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BernieD said:
Tom

One rule of thumb is 100 pounds weight per horsepower, so the 260 engine should be able to handle total weight of up to 26,000#s, maybe kind of slow climbing, but you'll make the top.

A concern about increasing horsepower in an engine is the cooling system and transmission. They MUST be able to handle the extra heat and load the increased HP will create. I'd be very careful about any HP change.

This particular engine has a weak block. Cummins did come out with a 300 Version for the ISB275 but withdrew it quickly and did a block upgrade then returned with the ISB 300. In addition, FCCC discovered that the drive line and radiator was inadequate and they too did an upgrade before applying the new ISB 300. If one is a buyer of a used MH which has a 300; it would be worthwhile to determine whether it is one of the 100+ or so upgraded 275 or the redesigned ISB 300.
 

tmac

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Leo,

How could i tell that an engine advertised as a 300 was the real deal and not an upgrade of a smaller one?

Tom
 

Phil

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tmac said:
How could i tell that an engine advertised as a 300 was the real deal and not an upgrade of a smaller one?

You can give the engine serial number to Cummins and they can give you the original build information and any updates that may have been done.  They can also supply you a list of all the part numbers used in that particular engine.  Not free but reasonable.

Phil
 

blueblood

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chuck said:
Blueblood, are you talking about some of these blocks cracking, or just weak in general?

The block was adequate for 275 HP rating and thousands are doing well in service. In fact, I did the change iand then drove it 80,000 miles with no problem before selling recently.  It must be understood that engines are uprated because of low duty cycles in RV's so in this case the engine is a 260 HP uprated to 275. Calculations showed going further to 300 had the potential to raise failures to an unacceptable level.  So, a more robust block was designed and used in the 300HP.

Note - there were some earlier block failures on this engine but these were related to a foundry error not design and one should not mix apples and oranges.
 

chuck

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Thanks blueblood, good explanation, in fact I had one of these bad casting blocks, #53,  in my 2000 Winnebago Journey and had to replace it. The coach had 28000 miles on it and was out of warrentee, presently the 5.9  275 hp unit is running well and averaging 10 mpg. Cummins gave me a new block and the rest came out of extended coverage and me.




 

Chief Dave

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Tom ,  Just in case you did not get my email.  I recently returned from the NC FMCA convention.  Met several Cummins reps.  Please contact Kevin Goen, Cummins General Manager for medium duty sales at Cell (812) 350-5291, or phone (812) 377-3696.  I'm sure he can answer your question, or refer you to someone that can help.

Chief Dave
 

tmac

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Chief Dave,

Thanks for the interest and the info.

Tom

P.S., Got the e-mail also
 

Chief Dave

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Tom,? My wife, Kathy and I are looking to purchase a 2006/2007 Monaco Knight.? We are planning to full-time it for the next 5-6 years.? We choose the the Knight for the Cummins 330 engine as well as the storage inside and outside the motor home.? I think the 330 is the smallest engine I'm willing to accept.? It should handle anything the U.S. has to offer in driving and braking.? We now own a 1999 Monaco LaPalma.? 99 was the first year Monaco used the Ford V-10 engine.? Many ups and downs on the V-10 engine.? We had 12K on the engine when we lost two cylinders just driving in Florida.? That prompted the purchase of a diesel for full timing.

Dave C
 

Tom

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Dave,

I think you might be a little happier if you step up a notch in the Monaco line, even if you have to buy something a year or two older.
 

TheDude

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The chip upgrade as with any mod that is not from the factory requires some kind of personal monitoring especially if it with the power plant. I did the chip upgrade, but I also installed a pyrometer, and turbo boost pressure, to monitor what this chip is actually doing. I love it, the pyrometer is the only actual one you need to watch exhaust temp. Turbo boost is nice but not required. I get an extra 2 miles a gallon with the chip set to the lowest setting. I have had to return it to stock once while climbing but hey it took all of 2 minutes to do. But I love the extra mileage!
You can also go to large diameter exhaust pipe if heat is an issue.

Note: I am somewhat of a gear head anyways so I did the work myself. If thiis upgrade was done by a shop would be around 1k including chip (depending on which chip) If you are a "gas and go" driver I would not recommend it.

TheDude
 

29er

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Chip "upgrades" or a user adjustable OBD-II flash tool can give turbo diesels tremendous power and torque increases. Some model Chevy pick-up trucks have been "flashed" and dyno'ed, which upped the HP by 95 and torque by 70.... Now the downside...Coolers for the trans and oil are absolutely mandatory. If your engine is under warranty the chip upgrade, which is easily detectable even after the chip has been removed (your engine will always have the chip imprint) NULLIFIES YOUR WARRANTY!! The flash upgrade can be removed and can NOT be detected.... These chips and flashers don't really do much for gas engines despite the claims of their advertisements. As an owner and user of these items I strongly recommend motor home owners to NEVER use them. Driving 1/4 mile at wide open throttle is a heck of a lot shorter than from Montana to Tucson.
 
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