Tell me about your pre-EPA Cat C12 engine experience

bluwtr49 wrote:
. . . I think you observation that the C-12 saw limited use in MH's they were very popular with in OTR applications with 750,000 to 1,200,000 miles between overhauls.

From searching for C12 fuel economy, etc., most of the discussions I found were about C12 engines in OTR trucks (seems really common in dump trucks) and in marine (boat) applications.

I didn't want to put too much stock in that, since I figure they're probably tuned differently than the C12s used in a motorhome.

But 8.5 mpg is a figure I could live with, and it seems like a rock solid reliable engine.

Thanks!

Wayne

Just as a FYI, we took off from Lebanon, OR to make a short trip to Coburg, OR for service and I was thinking about this thread so I paid attention to the the fuel consumption at different speeds...something I don't normally do since only the long term avg for our whole trip is important.

Heading S on I-5, ideal conditions flat and no wind with Cruise set at 55 the rolling avg varied from 10.3 to 11.5. Coach wt is ~32,000 and we were pulling a 3800 lb toad.

Returning N on I-5 pretty much the same conditions but cruise at 63 the rolling avg varied from 8.9 to 10.1.

I think the speed was difference between N and S.

Regardless, in order to get our overall trip avg of 8.5 some legs in the 10 to 11 range is reasonable which offsets the 3.5 to 5.5 climbing hills and such.

I think you observation that the C-12 saw limited use in MH's they were very popular with in OTR applications with 750,000 to 1,200,000 miles between overhauls.

Two Jayhawks wrote:
. . . Maybe you should share what coach you are looking at and let others weigh in on other aspects that are important also.

I didn't want to say what coach it was, because I wanted feedback on the C12, not other aspects of the coach. I didn't want to highjack my own thread. :)

Given the small number of responses, I suppose the C12 is not a terribly common engine in RVs. Seems like most mentions of it came from owners of Safaris or Beavers, both here and in the extensive internet searching I've done.

Ivylog -- Mileage can matter at lot. In my searching, I came across several people reporting mileage in the neighborhood of 5 mpg. I think those may have been post-EPA changes C12s. The owner of the coach we're considering says he gets 10+ mpg. (I should note that he claims that mileage on the "flat and level" and he makes no mention of his speed.)

The the fuel cost difference between 5 mpg and 10 mpg over 7500 miles per year times 5 or 10 years would be considerable. The other coach high on our list will return 7.5 to 8 mpg. Since it is a close decision on which one we like best, a significant difference in operating costs over the time we expect to use it could be the deciding factor.

BTW, the coach we're considering is a 1999 Safari Continental 425 Panther. I do worry a bit about the age of the coach, not so much regarding the running gear, but with respect to the house and its mechanical systems.

Wayne

Sounds like a Beaver Patriot Thunder... a great MH with 3406/425 HP Cat engine. Agree the Silver Leaf should know for sure and with a easy right foot, 55 mph cruise, and no big mountains, 12 might be possible. Not sure why we worry so much about MPG as the a difference of 1 MPG will be less than $300/year based on 7500 miles/year. If it has air over hydraulic brakes check for any recalls.

Trust me - you will NEVER regret having the additional HP and torque.

Wayne
My experience is all positive. My C12 powered coach has been mine since 2006. It has been reliable and eager with every turn of the key. Mechanical issues with engine have been ZERO. You need to pay attention to the engine braking difference larger diesels have over smaller ones. In the highest stage the C12 engine brake is large. MPG info will only be useful if we are talking identical units. Mine only weight about 25K and returns in the mid nine's effortlessly. If I drove 55 it will return an honest 10-10.5 all day long.

Maybe you should share what coach you are looking at and let others weigh in on other aspects that are important also.

Maintain a friends C12...on trips when we refuel the gallons use are usually within five or so with my old 3126 CAT and about the same with my current ISL. Good engine low rpm torque curve. It would be my choice if the rest of the coach was fine. :) :)

I like our C-12 a lot but mileage in the 10+ range occurs quite seldom...think more like 8.5 as a consistent average over time. You will love the effortless cruising at 1300 rpm and the Jake brake is like throwing out an anchor. The tranny is probably the 4060 Allison and our gear ratio is 3.43:1.

FYI, there is a function in the Silverleaf that show the avg MPG since the engine was born...have the owner pull that screen and there will be not boubt. By the way, the Silverleaf is a great device and I've found it to be very accurate. Put that on your must-have list.