Consdering Going To DP -- Questions On Engines

[CarlAda]

Currently, we are in a 2008 Jayco Seneca 35GS with a Duramax engine. We are strongly considering moving up to a Class A DP. Now, I know very little about diesel engines, which is the reason for my query.

To date, we have test driven a 2006 Beaver Patriot Thunder 42ft with a Cummins 525 HP engine and a 2008 Monaco Beaver Contessa Pacifica 40ft with a Cat C9 425HP engine. I'm not looking for pros and cons of any specific coach, but would like to hear some pros and cons of the different engines (and chassis), although I realize much of this is personal preferences).

Are there any engines to definitely steer clear of with regards to maintenance and repair issues? Any strong contenders to look for?

I realize that the year of these coaches (and the ones I'll likely consider in the future) put me right in the age of changes with emission controls. Currently, the Duramax that I have has DPF and I'm a bit aware of some negative issues that imposes. Emission control issues with any particular engines?

The two models listed above are ballpark of the coaches that we're looking at, a price range under 200K, 38-42 foot to give you an idea of what we're considering.

[medico]

I have had good luck with a Cat C13, 525 HP diesel. Both Cat and Cummins are good choices. I believe Cat has discontinued engines on new coaches, unsure why.

My C13 gets about 6.5 MPG average while setting my cruise at about 62 on the highway. For my size and weight coach this seems quite good.

[huffypuff]

Medico, Cat got fed up with the emission and dropped out of over the road application. Carl, both vehicle are a great choice with their engines so it would depend what you are looking for in a coach.

[kaypsmith]

Cummings and Cat engines are both very good engines. The biggest drawback for cat in a motor coach is there are fewer repair facilities that are equipped to repair in the coach.<br />Many stories are that the repair facility did not leave the inside of the coach as clean as the owners would not like them to. Not in disregard to Cat, as they are very good engines.<br />Not many motor coaches use Detroit, the C60 is also a very good engine

[tbutler]

Cummins does a great job of catering to the RV community. We're on our way to the Regional Cummins facility in San Antonio. We've been going to the Cummins Distributor there on a regular basis. We've used distributors in Phoenix, Denver, Arcata-CA, Anchorage, Regina-SAS, Bakersfield, Chehalis-WA, Billings-MT, and others. Cummins also has Coach Care facilities that are specialists in servicing motor homes. The Coach Care facilities are not everywhere but we've always found excellent service at the distributors and the authorized service shops for Cummins. Check your local area and see if there is a dealer near you. I'm betting you'll find one nearby. If it isn't a distributor (large cities only, US and Canada), you can get your work done near your local community. We've been able to get service on the road when we needed it. Full time for almost 10 years and I can't imagine better or more convenient service.

Cummins owns Onan and they service our generator while we are there. Cummins is the over the road standard and you can find authorized shops in almost any town. Cummins has representatives at almost every FMCA Convention and they offer service on your generator on site. You will find other engines in RV's but I'd bet that most that you look at are Cummins engines. Parts and service where you are, you can't ask for more than that!

[CarlAda]

I thought that I recall reading some very negative comments regarding the Cat C9 engine. Was that just internet banter or is there something to that?

Thanks for the comments so far. It has been useful info.

[obedb]

Detroit's Series60 is a very good engine. I know that they are available in Prevost conversions. Take a look at at them as a used DP.

[CarlAda]

Another question please......when I test drove the 08 Monaco with the Cat engine, at very low speeds (i.e. just taking off, less than 10mph), I noticed the engine seemed to rev higher with less acceleration. At speeds higher than 10 mph (and 10 is a guess), I did not notice any such behavior. Is this typical? Was I just simply applying too much gas? It wasn't like it was racing, just slightly elevated engine rpm to acceleration. This wasn't measured by any indications. Just my ear.

[wolfe10]

Carl,

I am trying to make sense of it, but can't. The same transmission and quite likely the same rear axle ratio and tire size is used with other engines of similar displacement. These factors determine engine RPM-- the engine really is "just along for the ride".

Would be interesting if you find one of these factors different with a particular engine: Transmission gear ratio in first gear, rear axle ratio, tire size-- actually tire revolutions per mile.

[CarlAda]

Perhaps I wasn't quite clear in my explanation of events. From a dead, or near-dead stop, I press on the accelerator to move forward. As I press down on the pedal, I hear the engine rev slightly higher than I would expect for the pressure applied to the pedal. As the coach picks up some speed, that rev tapers off. It doesn't feel as if there is any slippage or similar mismatch.

It's probably mostly my inexperience with driving these type vehicles and may not be an issue at all. I will admit that at the time that I noticed it, we were in a road construction area with tight clearances, so I was quite easy on the pedal and moving slowly between the construction cones and guardrail on the side of the road.

[dickandlois]

CarlAda,

The coaches we have owned over the years have all had some engine issues. The engines and drive trains all need general maintenance.

Then there are issues that require specific repairs to regain original performance.

The items vary between gas, diesel or even CNG because of the different fuel delivery system the fuels require.

Gas engines rarely use turbo chargers, where both diesel or CNG engines they are common. So an exhaust leak, waste gate or VGT system can have a profound affect on the coach's performance when something in the loop fails and it can be as simple as a failed fuel line to a complete failure of the turbo spool.

You will find owners that love there Cat, Cummins, Detroit, Ford, GM or Mercedes engines and you can also find owners that have had a bad experience with more then one engine manufacture.

I have had my share of valves failing, blown gaskets, failed fuel pumps, water pumps and the list goes on and on.

I have a saying, that they never fail when parked, but that is also a problem; if things set for to long with out a good 20 to 30 mile run now and then.

One needs to decide how many horses to have in the barn and how much they want to pay for the Oats(in this case how many gal. of fuel).

A friend had his large coach re-powered. Meaning he changed the engine(Complete Engine Failure) and everything directly connected to the engine replaced. The transmission and rear differential where left OEM and set up to work with the Engine. Last time I contacted him, the coach was getting around 20+mpg running up the Grape Vine>@70mph and he is not the type that is full of BS. But there is always a cost factor !!!!

Rich.

[wolfe10]

Carl,

I suspect you heard the turbo spool up (increased noise level). Newer diesel engines meeting the stricter EPA specs do generate a lot more boost at lower RPM/throttle settings than earlier engines.

[CarlAda]

Thanks Brett....that makes a lot of sense. As I said, I have very little experience driving a DP and it's quite different from driving a gasser or even my diesel super c! I'm excited about going to a DP ... now it's just a matter of finding the right one that fits our needs and desires. You guys have been a terrific help and I suspect will continue to do so. Plan on joining the Diesel RV club soon as I'm guessing there's a wealth of information there.

[jleamont]

CarlAda, heres my two cents, they all have their pros and cons, some have more cons than pros, heres a few to look out for; Maxxforce powered (all) and CAT powered (2007-2008 engines, the last ones before throwing in the towel). You can check the internet to see all of the class action law suits on the last batch of CAT on highway products and the Maxxforce line up. International Navistar reciently put Cummins back into their trucks as an option to save them selves from a horrible end. In my career I deal with these problem children each and every day. Not to say that a Cummins or Detroit product will not give you a headache but some are known to be worse than others.

Good luck with your shopping, we just moved into our 1st DP in May from a Gas Class C, just wish we did it sooner.

Joe

[wigginsjsr]

CarlAda, heres my two cents, they all have their pros and cons, some have more cons than pros, heres a few to look out for; Maxxforce powered (all) and CAT powered (2007-2008 engines, the last ones before throwing in the towel). You can check the internet to see all of the class action law suits on the last batch of CAT on highway products and the Maxxforce line up. International Navistar reciently put Cummins back into their trucks as an option to save them selves from a horrible end. In my career I deal with these problem children each and every day. Not to say that a Cummins or Detroit product will not give you a headache but some are known to be worse than others.

Good luck with your shopping, we just moved into our 1st DP in May from a Gas Class C, just wish we did it sooner.

Joe

I'm not sure where you get your information, but you have a lot of misinformation regarding Maxxforce. Navastar's MaxxForce 10 engines have been used very successfully in motorhomes. Mine has 31,000 miles without a problem. Navastar has not started putting Cummins engines in their trucks. They had a problem with their higher end, over-the-road, engines meeting the EPA requirements using the same technology they have used successfully on the MaxxForce 10; therefore, they have adopted the Cummins exhaust technology in their larger engines. My MaxxForce 10 does not require DEF, and has significantly more torque (1150 lbs) compared to a Cummins of similar displacement.

[jleamont]

wigginsjsr,

Source came from Navistar corporate and our rep with his tail between his legs. In 2012 I HAD to purchase 1100 power units for our fleet, they average 15,000 miles between breakdowns and NONE have made it to 200,000 miles before something catastrophic happened.

We purchased an additional 900 power units in 2013 the results were worse. Unfortunately with a large national fleet we have to "spread out the wealth" so I am told.....fortunately with the amount of purchasing power we get good support from them but we are all frustrated with the constant breakdowns and unreliability of their product.

Good luck with that engine, if you ever experience any problems feel free to lean this way, I would be happy to make a phone call for you and see if someone would be willing to help share the cost at their corporate level for you to get you back on the road.

[msturtz]

We purchased a new 2014 Thor Palazzo 33.3. I was surprised to be able to get a DP for basically the cost of a gasser. It has fewer frills than a typical DP, i.e. it has vinyl flooring, a basic steering wheel (no smart wheel), basic radio and gauge pack, no navigation. However, it meets our needs in the critical areas, payload, tank capacities, (water, fuel, waste, DEF) and has bunks for the kids. The cabinets aren't as well made as your typical DP either. Again I don't care. I do like the fact that most outlets in the unit are powered by the inverter.

It has a ISB 300 6.7L. Seems like a small engine for a 26,000# GVWR / 30,000# GCWR unit and an Allison MH2100 transmission. An interesting factoid is Thor put it onto a Freightliner XCS 28,000# GVWR / 30,000# GCWR chassis but de-rated it to 26,000# / 30,000# because of the Allison MH2100 transmission limitations. I have found that it is OK for what we are doing and gets excellent fuel mileage. Like I get better fuel economy than in my Tahoe! You can get the new Palazzos for between $130K to 150K and used ones are typically in the low 100K range.

I strongly recommend that you avoid any Palazzo that has not had the large slide rail system upgraded or repaired. Most of the Palazzos had major issues with the large slide. Thor used undersized motors and insufficient rails. If you can get a good deal on one just put it into the contract that they have to fix the slide system and or upgrade it to the 3 rail system. Our unit is the shorter of the bunch they do have units that are 36' long with an Allison MH2500 Cummins ISB 340 and 28,000# GVWR 33,000# GCWR.

Have fun in your search!