Cat vs. Mercedes?

[KKlepfer]

I'm in the process of configuring an RV. I am interested in the Dynamax RV with the Freightliner M2 chassis. I love my Cummins I6 but it is not offered in the Freightliner and don't have any experience with other diesels.



The Freightliner offers two engines. The Mercedes is standard 6. 4 L, 250 hp @ 2200rpm, 660 lb/ft of torque @ 1200rpm. The Cat is an upgrade that has 300hp @ 2200rpm and 860 lb/ft of torque @ 1440rpm. I know from this that the CAT is a stronger engine, but is one more reliable and less to maintain than the other?



Any thoughts on which one I should choose?

 

[DonTX]

Having spent some time on the road, I would vote for the Cat. I not only have many happy hours behind a cat, but believe they are great engines. I ALSO have many happy miles behind a Mercedes. Problem is service the way I see it. If I were touring Europe, the Mercedes would win hands down.

I travelled extensively the last two years in a "faux Mercedes". No matter where I pulled in, someone would run out when they saw the stars and shout "we don't do Mercedes".

 

[JFaulkner]

I don't know which would be more reliable. However your more limited to where you can get parts for the Mercedes and places to get it serviced (freightliner dealers). The Cat can be done at just about any large truck dealership, not to mention Cat equipment dealers. I know that this shouldn't be an issue if it's "reliable" but all things break sometimes, and better to break something you can more easily get parts for. There's no doubt that the Mercedes is probably a good engine so your probably pretty safe with either, but depending on the size of the RV the higher hp might help with mpg.

 

[TWilkening]

I don't know which would be more reliable. However your more limited to where you can get parts for the Mercedes and places to get it serviced (freightliner dealers). The Cat can be done at just about any large truck dealership, not to mention Cat equipment dealers. I know that this shouldn't be an issue if it's "reliable" but all things break sometimes, and better to break something you can more easily get parts for. There's no doubt that the Mercedes is probably a good engine so your probably pretty safe with either, but depending on the size of the RV the higher hp might help with mpg.

You hit it right on the head. I'm sure as long as Mercedes has been building diesel engines, they are pretty good. But no matter how good it is, it will require parts at some point in time. I know Cat parts ain't cheap, and I doubt Mercedes are either. Not to mention having to try and find a dealer.

 

[DBogo]

well parts for mercedes are available through detroit diesel so thats one thign to concider

 

[DonTX]

Wow, DBogo, I sure did not know that. Is that ALL DD dealers?

 

[DBogo]

im not positive but i know detroit destributes mercedes engines, so parts and service should be available at the detroit dealers, i will ask a guy that i know who works for detroit and get back to yall

 

[Phrogger57]

Yep, guys, DC owns Detroit Diesel. All DD dealers SHOULD be fully certified to work on the Mercedes engines. The engine lineup goes something like this:

M-B 900 series- largest being a 7. 2 L 330 hp/1050ft. /lbs

M-B 4000 Series ? displacement, up to ( I think) 425 hp

DD Series 70 - displacement to 12. 7 L HP to ?550?



That being said, both companies (Cat & Mercedes) feel their parts are precious.



I chose a M-B 926- 7. 2 L 300 HP/ 850 Ft. Lbs for my M-2. The 330 was still undergoing Engineering for cooling issues in the M-2 chassis when I ordered, but it is a currently available rating. Part of the issue for me was the "upcharge". Freightliner, being a DC company, had a much larger upcharge for a Cat or Cummins in the M-2 than their (house) engine.



I love the power (torque) of my 926, and get pretty good fuel economy for what I do (was RV hauling, now car hauling on wedge trailer). Has not been without problems, but Freightliner has been good as gold in dealing with me.



Bottom line (from my warped viewpoint)- see if they will uprate to a larger mercedes (ie the 330/1050) cheaper that the CAT. Basically, look at the bucks- both have excellent support systems, and it comes down to what works the best for you and your application.



Happy Dieseling. -Eric

 

[KKlepfer]

Thanks for all the feedback. I am very appreciative of all the insight and advice. My concerns have all been met by your feedback and I am pleased to hear insight from someone who actually owns a M2 chassis. Thanks again for those who have taken the time to respond.

-Kirk

 

[MKoth]

Don't forget that the Cat motor will be a HEUI setup (same as the 7. 3L and 6. 0L), and the Mercedes will be common rail.



I would pick the Mercedes just for the more reliable fuel system.

 

[benhall]

If you go with the Sterling Acterra line of trucks, you can get a Cummins ISC under the hood. Sterling is owned by DC as well.



Ben

 

[therabbittree]

Having driven the cat engine in a small dump truck I would go with the mercedes. . I think it is better design , last longer, and if i remember last time i looked at the mercedes brochure you could get a compression and exhaust brake for it. . My friend works at a detroit dealer and says very good things about the mercedes engines.

Thanks

Deo

 

[Headshot zod]

hmmmmmm..... I saw cat vs. mercedes, saw an attachment and was thinking of something completely different

 

[DBogo]

i talked to the guy i know that works for detroit diesel they carry all the parts for the mercedes MBE diesels and they also service them at any of the detroit dealerships

 

[nps]

My son is a mech at the local Cat dealership working on OTR trucks and motorhomes. When I was looking at diesel pushers he said to stay away from the C7 Cat motors because of all the HEUI problems. C9s and up don't use HEUI and are solid.

 

[tgee]

Yep, guys, DC owns Detroit Diesel. All DD dealers SHOULD be fully certified to work on the Mercedes engines. The engine lineup goes something like this:

M-B 900 series- largest being a 7. 2 L 330 hp/1050ft. /lbs

M-B 4000 Series ? displacement, up to ( I think) 425 hp

DD Series 70 - displacement to 12. 7 L HP to ?550?



MBE 4000, 12. 8 liter, to 450 HP DDseries 60, 12. 7 or 14 liter. Work on MBEs, only big problem I've seen is wrong fuel filters installed, or leaving a plastic base of an old filter in the can and putting new filter on top, which damages it.

 

[mhuggler]

As a Cat truck engine tech, I'm feeling compelled to share an opinion. :-laf Sadly, my choice between the two would have to be the Mercedes. C7's seem to have alot of bugs on the electronic side of things. The C7 injectors are even more complicated(read:failure prone) than the previous 3126 style(like the powerjoke). They have more power, but rarely run smooth. BTW- the C9 is a Heui engine like the C7 but you would never tell. They run very smooth, have massive power, and are way more reliable than the C7. Actually, it would be my first choice for an RV motor. In an RV, they're available in 400hp and 1150 ft. lbs! They even throw a little soot out the pipe! :-laf