Community Forums

discovery39s · 02-24-2016, 04:39 PM

Hello everyone,
Hope today finds everyone well. Well, after owning gas class A's for many years my wife and I found a one owner 2004 Discovery39S that is absolutely gorgeous. She has 49K miles and stored in a heated building her whole life when not on the road. Looks like new, top, bottom, body and interior.

I'm all new to the Cat 330 and in hopes those who know this unit well may be willing to share some experiences, good and bad. We travel to Florida down 75 out of Ohio and curious on climbing the Jellico mountains with this unit. We pull a 1,200 lb. boat and interested in hearing from all on its climb ability expectations.

Thank you in advance for helping out a newbie diesel owner
Travel safe!

APhotoWizard · 02-24-2016, 07:03 PM

Welcome to the forum -

I drive a 40 ft 15 ton Tiffin Allegro Bus with a Cumming 330 engine so I should have about the same power as you. I pull a 5,000 pound Jeep which is lighter than your boat.

I also previously owned a gas burner and I would never go back. The diesel will climb faster and with a retarder installed come down the mountains safer than the gasser ever did.

I have driven the Interstate from upper Ohio to Orlando and back with my rig and never had any problem. I have been able to keep up with or pass tractor-trailer combinations even when climbing the hills.

There were times in the mountains out west where I had to drop to a lower gear thus had to slow my ground speed, but most of those times the speed limit was reduced on the road anyway so no one noticed. The key thing is to select a gear that keeps your engine turning fast enough to generate the needed power without over revving. For my engine that is around 2100 RPM.

Watching the tachometer is the major difference I found between the gasoline and the diesel engine. With a gasoline engine you just press the gas harder to go faster and get more power up to the red line rpm which is usually 4400 RPM or more. The diesel produces power at much lower rpm and has a much lower red line. My rig idles at 600-700 rpm and the governed maximum is 2900 rpm. Yours should be similar.

One more note. You said that you only have 45,000 miles on the rig. The Cummings people tell me that their engine is not fully broken in until 100,000 miles and does not get it's best fuel economy till then. You still have a ways to go.

In summary - Just get in and go. You will not have any trouble. Just relax and enjoy the ride.

Mr_D · 02-24-2016, 07:15 PM

The Cat will have an exhaust brake. The only RV that uses a retarder is Foretravel and it's built into the Allison transmission.
The Cummins and CAT are two different engines even though the HP is about the same. The CAT will have 860 ft lbs, the Cummins ISB will be less, depending on it's state of tune.
Our 2000 Dutch Star had the 300 CAT and I found it to have less torque than I wanted out here in the West, but that's purely a personal choice. The CAT will get you up anything you should ever meet, just not as fast as some.

Taterpeeler · 02-24-2016, 08:50 PM

Quote:

Originally Posted by Mr_D

The Cat will have an exhaust brake. The only RV that uses a retarder is Foretravel and it's built into the Allison transmission.

Hmm... on my side arm rest it says Retarder... must be incorrect label on the arm rest

dls461 · 02-25-2016, 08:06 AM

I have the 05 39S with the C7 330 hp Cat. The key is to make sure your rear radiator and CAC units are clean. If the slobber tube has not been extended or have a catch can, one should be added. The other thing to remember is that the engine needs 19 qts of oil with filter change not the 22 qts the manual calls for. This reduction of oil amount will reduce the "blow by" which causes the clogging of the radiator and CAC. Other than that, it should roll over anything you encounter on your tirps. I have many trips out west and never any issues. I have approx the same mileage as yours. As stated earlier, the tach is the most important guage when climbing. Keep the RPM's around 2000 and you should be good to go.
Enjoy!

CodeMonkey · 02-25-2016, 11:54 AM

Quote:

Originally Posted by Mr_D

The Cat will have an exhaust brake. The only RV that uses a retarder is Foretravel and it's built into the Allison transmission.
The Cummins and CAT are two different engines even though the HP is about the same. The CAT will have 860 ft lbs, the Cummins ISB will be less, depending on it's state of tune.
Our 2000 Dutch Star had the 300 CAT and I found it to have less torque than I wanted out here in the West, but that's purely a personal choice. The CAT will get you up anything you should ever meet, just not as fast as some.

My Fleetwood Expedition also has a retarder- at least that is what the button says.

Mr_D · 02-25-2016, 12:05 PM

Labels can say anything, but it's what's on the engine that counts, but you don't have the Allison retarder. The Allison retarder has a "joy stick" beside the driver. If you have an exhaust brake you just have an on-off switch, for the engine brake you will have an on-off switch and then a second switch to select the amount of holdback.
You don't get an engine brake till they get to the C-9 in CAT's or the ISL in Cummins and even then there are a few ISL's that have an exhaust brake.

discovery39s · 02-25-2016, 02:52 PM

Wow,
Some great info and I do appreciate it. my rig does have a switch for engine brake and during the extended test drive it really made a difference not only in downhill conditions but also normal stopping.

I had a Workhorse chassis prior and I can say it had a lot of power and climbed very well. I'm comfortable to hear everyone's input regarding the power. No, I'm not in a hurry, just wanted to better understand what she wants setting up for an extended grade.

The test drive alone convinced me that I will not go back to a gas rig. This coach was silky smooth on some not so good roads and the wife was impressed at the noise reduction. Simply amazing the difference.

The prior owner was very informative of the radiator maintenance and other specific do's and dont's and thanks for the additional heads up.

Its my understanding that its all about keeping the temp well within the acceptable range or real bad things can happen. One exhaust muffler manufacture claims that their muffler will reduce exhaust temperature due to its unique design. Has anyone tried one of these? Are their claims accurate?

Thanks again everyone for you have been a lot of help!
Travel Safe

mchero · 02-25-2016, 03:37 PM

2 years on our 07 Discovery. Had 20K on her. We now have about 20K on her. LOVE the XC chassis, turns on a dime. Any service records? Sounds like prior owner kept her up.
Keep the oil changed both CAT & generator. Keep a CLOSE eye on that rear radiator!

Taterpeeler · 02-25-2016, 10:34 PM

I think I will now sue... false information on the label, I shall call you as a witness.... I have the ISL

Mr_D · 02-25-2016, 11:07 PM

Quote:

Originally Posted by Taterpeeler

I think I will now sue... false information on the label, I shall call you as a witness.... I have the ISL

Your ISL probably has the engine brake as the exhaust brake was only used (as far as I know) on the 370 hp version.
Been deposed in a wrongful death suit already as well as two juries, one as foreman.

APhotoWizard · 02-26-2016, 12:22 PM

One note on the radiator. I felt my engine overheated too quickly when I purchased the rig used, but no one could see a problem. I took the rig to the shop to get the shocks replaced and the mechanic called me to look at the engine. He noted the radiator was plugged up. I was sure the radiator was clean.

What he showed me is that, at least in rear engine configurations, cleaning the side of the radiator you can see from the rear does minimal good. In a diesel pusher the back wheels throw the road dirt and grime up an directly into the engine side of the radiator.

In my rig it is hard to even see the problem from the top, but with the rig on a lift it is easy to see that my radiator was indeed over 50% blocked. He cleaned it and now I hardly ever see the temp gauge rise over high normal except on exceptionally long grades when I forget to gear down properly.

mchero · 02-26-2016, 01:04 PM

Quote:

Originally Posted by APhotoWizard

One note on the radiator. I felt my engine overheated too quickly when I purchased the rig used, but no one could see a problem. I took the rig to the shop to get the shocks replaced and the mechanic called me to look at the engine. He noted the radiator was plugged up. I was sure the radiator was clean.

What he showed me is that, at least in rear engine configurations, cleaning the side of the radiator you can see from the rear does minimal good. In a diesel pusher the back wheels throw the road dirt and grime up an directly into the engine side of the radiator.

In my rig it is hard to even see the problem from the top, but with the rig on a lift it is easy to see that my radiator was indeed over 50% blocked. He cleaned it and now I hardly ever see the temp gauge rise over high normal except on exceptionally long grades when I forget to gear down properly.

This exact issue has been discussed MANY times on this forum. It's a fact of life, rear radiators are a PITA! I have also hear of people harping about how clean their radiator is but quickly change their tune when they actually see the backside!
Some have actually cut a door on the top of that giant fan shroud. You can then get down in their with a sprayer & then douse the backside with Simple Green. Just a real PITA when your full timing.

Bigd9 · 02-26-2016, 01:35 PM

Quote:

Originally Posted by discovery39s

Hello everyone,
Hope today finds everyone well. Well, after owning gas class A's for many years my wife and I found a one owner 2004 Discovery39S that is absolutely gorgeous. She has 49K miles and stored in a heated building her whole life when not on the road. Looks like new, top, bottom, body and interior.

I'm all new to the Cat 330 and in hopes those who know this unit well may be willing to share some experiences, good and bad. We travel to Florida down 75 out of Ohio and curious on climbing the Jellico mountains with this unit. We pull a 1,200 lb. boat and interested in hearing from all on its climb ability expectations.

Thank you in advance for helping out a newbie diesel owner
Travel safe!

We have the 2006 version of the coach, and for me I find the Cat C7 engine is great for the coach and towing our 3,500 pound Honda CRV. We put 14,000 miles on her last year, and 8,000 the year before. Living near Lexington Ky, we have had the coach/toad over the Jellico mountain probably half dozen times and absolutely no problems. We have been over the Rocky Mountains 4 times with her and although we slowed down to 45/50 mph, she did not even flinch on temperatures. This winter we took her into the mountains of West Virginia snow skiing and I was amazed that I had to slow her down going up some pretty steep small roads.

I am the type who lets the engine/transmission computer do its thing. I never downshift but occasionally will hold a gear when she is "hunting" between two gears too much going uphill.

The coach has a exhaust brake that works VERY well coming down mountains. On Jellico, I rarely have to use the service brakes.

We get 7.6 mpg on average over the 22,000 miles all towing the Honda.