FGV 40' with DD 6V92

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FGV 40' with DD 6V92

February 04, 2017, 10:42:15 am

I am in the market for a early 90's FGV and have located a 1994 FGV 40' with a DD 6V92 and Allison 4 speed.

1994 Foretravel UNIHOME 3600 U300, GALLATIN TN - - RVtrader.com

This coach is near me. I have not physically looked at it as of this moment. I have contacted the owner and have been invited to see it. 2 big issues for me: I would rather have a 36', and the engine. I can probably handle the length. It is the engine that is worrisome.

I have no experience with driving large diesel trucks and coaches. After having identified this coach on RVTrader, I researched the DD 6V92. I know it is a 2 cycle and have read what that entails. We spend a lot of time traveling steep, paved, mountains roads.

I suspect that if we were to go look at it we would be sorely temped to buy it. The owner could probably talk me into accepting the challenges of owning the DD. I am not sure I can handle it.

The engine seems to need someone who has a high degree of operating skill and knowledge. Is this something a novice like myself should even consider buying?

Any thoughts will be appreciated.

Re: FGV 40' with DD 6V92

Reply #1 – February 04, 2017, 11:14:36 am

The Detroit 2 cycle is the most produced heavy duty engine in the world with over 3.5 million made and 700,000 still in use. Mercedes purchased Detroit back in the 90's and still makes new 92 series. They could have purchased Cummins but chose Detroit for a reason. Some 6-71 Detroits in railroad generators have never been overhauled!

The 6V-92TA Detroit was the only engine I considered when shopping for a Foretravel. Also had to have a 36 footer for our western campgrounds. I have been driving the 2-cycles in fire trucks since the 1960's and owned a Greyhound conversion with it's 8V-71 engine.

It puts out more torque at a lower rpm than a four cycle, runs a 150 degree lower exhaust temp so no dropped valves, glass smooth at any rpm, gets good fuel mileage (7.9 mpg over the life of our coach), all are computer controlled so no "RACK" to run, built in aftercooler (like some CATs), etc, etc. At 350 hp, it's loafing compared to typical boat installations of 535 hp for the same engine.

Nothing wrong with a Cummins or CATs but my favorite is the 2-cycle. The only negative is the 4 speed Allison. It's super strong but the 6 speeds have much better ratios.

PM with concerns/questions.

Pierce

Re: FGV 40' with DD 6V92

Reply #2 – February 04, 2017, 11:16:09 am

There is a discrepancy in the listing. If it is truly a model 3600, it is 36 foot long. The U300 was the top of the Foretravel line in 1994. Depending on the condition, it could be a great coach. The detroit diesels are not junk engines. They have a pretty large following on Foreforums.

If it is near you, go look at it. You will learn more about Foretravels than you know now.

Good luck,

Trent

Re: FGV 40' with DD 6V92

Reply #3 – February 04, 2017, 11:29:16 am

I took a look at the photos and pretty sure it's a 40 footer. The special edition was only 40 feet. Would want to call to make sure on the specs. No engine photos but if it's a 1994 U300, is has a Detroit in it. It's not a 1995 as it does not have the front and rear updated access doors.

Pierce

Re: FGV 40' with DD 6V92

Reply #4 – February 04, 2017, 11:47:20 am

Quote from: Pierce & Gaylie Stewart – February 04, 2017, 11:14:36 am

The 6V-92TA Detroit was the only engine I considered when shopping for a Foretravel. Also had to have a 36 footer for our western campgrounds. I have been driving the 2-cycles in fire trucks since the 1960's and owned a Greyhound conversion with it's 8V-71 engine.

It puts out more torque at a lower rpm than a four cycle

Sorry, but that torque statement isn't accurate. The Detroit 6V92TA puts out 957 lb-ft@1200 RPM, while the Cummins M11 in our 1995 U320 puts out 1350 lb-ft@1200 RPM. That's more than 40% more torque for the four-stroke engine. The Cummins M11 also puts out its rated horsepower at 1800 RPM compared with 2100 RPM for the two-stroke Detroit.

Re: FGV 40' with DD 6V92

Reply #5 – February 04, 2017, 11:49:12 am

All I know after being on this forum for a while, is, "Diesels are diesels are diesels." Like brands of beer, we all have our favorites.
I believe it is a 40', looks like it might have the rear-mount radiator, rather than a side-mount. Good looker, as usual, not much info on upgrades or service records. I'd go look at it and talk with the owner. A forum member to help inspect her is a good idea!

Re: FGV 40' with DD 6V92

Reply #6 – February 04, 2017, 11:52:38 am

Quote from: mike leary – February 04, 2017, 11:49:12 am

All I know after being on this forum for a while, is, "Diesels are diesels are diesels." Like brands of beer, we all have our favorites.
I believe it is a 40', looks like it might have the rear-mount radiator, rather than a side-mount. Good looker, as usual, not much info on upgrades or service records. I'd go look at it and talk with the owner. A forum member to help inspect her is a good idea!

The pictures (both exterior and the bathroom layout) show that it's a 40-ft model and the right-side picture shows it has the side radiator.

Re: FGV 40' with DD 6V92

Reply #7 – February 04, 2017, 12:15:27 pm

Just keep in mind the $17,000 that is being spent on another post for a rebuild, great engine yes but have to wait weeks for parts.

Re: FGV 40' with DD 6V92

Reply #8 – February 04, 2017, 12:29:18 pm

Quote from: D.J. Osborn – February 04, 2017, 11:47:20 am

Sorry, but that torque statement isn't accurate. The Detroit 6V92TA puts out 957 lb-ft@1200 RPM, while the Cummins M11 in our 1995 U320 puts out 1350 lb-ft@1200 RPM. That's more than 40% more torque for the four-stroke engine. The Cummins M11 also puts out its rated horsepower at 1800 RPM compared with 2100 RPM for the two-stroke Detroit.

Now you're comparing apples with oranges. The 6V-92TA is 9 liters and the M11 you quote is 10.8 liters. The M11 was never installed in a GV. In comparing GVs, the engines available in the U280 and U300 were Cummins 8.3 liter in the U280 and the 9 liter 6v-92TA Detroit in the U300. The six speed transmission used behind the 8.3 Cummins could not be used behind the U300 as the Detroit put out too much torque and was not within the Allison specs. So, 8.3 Cummins "C" engine produces about 860 ft lbs of torques compared to 1020 @ 1200 rpm in the 6V-92TA as installed in our Foretravels. The 8.3 is also a slightly higher rpm engine but allowing for the .7 liter of displacement difference, the rpm is about the same per liter of displacement.

Detroit Torque Specs: http://www.dwclutch.com/D&W/D&W%20Clutch%20&%20Brake%202/DETROIT%20TORQUE.pdf

As you can see here, the MD3060 Allison six speed has a limit of 950 lb-ft in RVs. This eliminates it's use behind the 6V-92TA http://jexler.s3.amazonaws.com/safari/data/Allison%203060%20specs.pdf The MD4060 was not available until 1995 so none of the U300 Detroits got to have the six speed.

Here is the actual dyno photo of a 6V-92TA putting out about 520 hp and 1200 ft-lb of torque: http://www.youtube.com/watch?v=3xy527eJ4Jw If you factor the displacement in at 1.2, the Detroit at 10.8 liters delivers about 1440 ft-lbs of torque. Yes, the 8.3 Cummins and the 9.0 liter Detroits could both put out more power/torque but this is not how they were installed in our Foretravels.

Update: looks like the 8.3 Cummins was updated to 300 hp in 1995 and went over the Allison 3030 torque limit so went to the 646 Allison four speed so a close contest.

You could have used the 15 liter ISX Cummins if you really wanted to beat up the Detroit.

Pierce

Re: FGV 40' with DD 6V92

Reply #9 – February 04, 2017, 12:31:29 pm

Quote from: John44 – February 04, 2017, 12:15:27 pm

Just keep in mind the $17,000 that is being spent on another post for a rebuild, great engine yes but have to wait weeks for parts.

True, but we also had a CAT owner that dumped big CBs into his 3116 a while ago. Luck of the draw. Pun intended: it mostly "boils down" to never overheating these hard working engines!

Re: FGV 40' with DD 6V92

Reply #10 – February 04, 2017, 02:05:32 pm

Quote from: Pierce & Gaylie Stewart – February 04, 2017, 12:29:18 pm

Now you're comparing apples with oranges. The 6V-92TA is 9 liters and the M11 you quote is 10.8 liters. The M11 was never installed in a GV. In comparing GVs, the engines available in the U280 and U300 were Cummins 8.3 liter in the U280 and the 9 liter 6v-92TA Detroit in the U300.

I am comparing "apples to apples." According to Foretravel History "The 1995 and 1996 U300's were very desirable and came with 370hp M11s uprated by Foretravel to 400hp. (these were all Unihomes) Cat 3176 350 could be substituted by special order (these are rare)."

The Cummins 8.3 was used in the U280 models and not in the U300 models. Foretravel used the M11 as the direct successor to the 6V92TA in their top-of-the-line models and therefore the comparison between the two engines is valid. The Cummins 8.3 was used in the lower-cost Foretravel models.

Re: FGV 40' with DD 6V92

Reply #11 – February 04, 2017, 02:21:17 pm

According to the factory Foretravel brochure for the U300 for the 1995 year, there is only the CAT 3176 engine available: 1995 Foretravel U300 Specifications

I do see the history section but nothing from Foretravel itself about M11 engines. Are there any U300 owners out there with M11 Cummins engines? Or is this possibly a one off, special order? For you U300 CAT owners, did you have a Cummins M11 option when you purchased your coach?

Pierce

Re: FGV 40' with DD 6V92

Reply #12 – February 04, 2017, 02:23:48 pm

Quote from: John44 – February 04, 2017, 12:15:27 pm

Just keep in mind the $17,000 that is being spent on another post for a rebuild, great engine yes but have to wait weeks for parts.

That is one of the major issues with Detroit two-stroke engines today. They haven't been used in new-over-the-road applications in the US for over two decades and it's getting more and more difficult to find parts for them and technicians familiar with working on them. They were used on premium motor coaches and motorhomes for several decades but those days are now well behind us.

Re: FGV 40' with DD 6V92

Reply #13 – February 04, 2017, 02:27:10 pm

Hi There, new member here - my first post.. I think I can contribute a bit - to pay back on all my lurking

Google'ing the VIN # - this FGV was for sale in KY for $51,000 in May 2010. Motorhome Hunter FREE Classifieds - Hunt, Gather and Buy new or used Class A...

Regarding the DD, I think they are the way to go. Marine [boat guys not military] guys know them well. Searching their forums may help you become better acquainted with the 2 stroke. -Nick

Re: FGV 40' with DD 6V92

Reply #14 – February 04, 2017, 02:28:16 pm

Quote from: Pierce & Gaylie Stewart – February 04, 2017, 02:21:17 pm

According to the factory Foretravel brochure for the U300 for the 1995 year, there is only the CAT 3176 engine available: 1995 Foretravel U300 Specifications

I do see the history section but nothing from Foretravel itself about M11 engines. Are there any U300 owners out there with M11 Cummins engines? Or is this possibly a one off, special order? For you U300 CAT owners, did you have a Cummins M11 option when you purchased your coach?

That's really of no significance. The Detroit 6v92 engine was used in Foretravel's top-of-the-line motorhomes (the U300) through 1994 and was replaced by Foretravel in 1995 in the U320, the successor to the U300, with the Cummins M11.

If you prefer to compare the Detroit 6V92TA to the CAT 3176B (10.2 liters), the 3176 ratings are 1350lb-ft @1200 and 350hp@1800.

Re: FGV 40' with DD 6V92

Reply #15 – February 04, 2017, 02:49:44 pm

Barringtons Diesel Club out of South Africa has a wealth of technical info including specs and manuals for our Cats, Cummins, snd Detroits. You can choose your engine from the engine list for specs, bolt torques, and shop manuals. If you become a member you can have access to all of the available manuals. Diesel engine specs, bolt torques, manuals

http://www.facebook.com/BarringtonDieselClub/

I love all of this good hearted debate as I am learning more and more technical data from you guys!

Just for fun and the right amount of Coach Bucks I would like to swap my 6V92TA Silver for an 8V92TA Silver in my 36' U300 which is under 27000 lbs and has an Allison HT746 trans that could handle it or swap to a six speed. An extra radiator plumbed in the front like Andy2's should handle the cooling requirements and an update to DDECIV for the electronics.

Jerry

Re: FGV 40' with DD 6V92

Reply #16 – February 04, 2017, 03:17:17 pm

Quote from: coastprt – February 04, 2017, 02:49:44 pm

I love all of this good hearted debate

I am not sure it is all that good hearted. Beginning to sound like teenagers of my era arguing Ford versus Chevy.

Trent

Re: FGV 40' with DD 6V92

Reply #17 – February 04, 2017, 03:18:19 pm

Jerry,

Since you have the only other U300/36 with a common floor plan, did you weigh yours? I often wondered what the weight difference is between the 36' and 40' is.

Yes, 8V-92TA in Prevost and Wanderlodges use the HT746 transmission. That would be the least expensive way to go. For a little? more, you could go with the 4060 six speed.

I followed a U320/M11 in city and rural traffic and from a stop light, he was gone before I could clear the intersection. The six speed is just great out of the hole. Roll on at highway speeds was another story where our coach was a tiny bit quicker until we found some hills where the big gap between third and fourth was our downfall.

With a 8V-92TA installed, I think you would need at least one aluminum radiator up front and then a way to get more coolant up their without the friction loss. My 4107 had a HUGE rear/side radiator driven from a PTO off of the Detroit. It never got off the thermostat even in the hottest weather and the steepest grade.

Rainy Saturdays are great to spend time arguing the merits of our toy's powerplants.

Pierce

Re: FGV 40' with DD 6V92

Reply #18 – February 04, 2017, 03:20:21 pm

Quote from: TulsaTrent – February 04, 2017, 03:17:17 pm

I am not sure it is all that good hearted. Beginning to sound like teenagers of my era arguing Ford versus Chevy.
Trent

Trent, if you drive a Cummins, don't step off the curb in front of me! I'm almost never serious....almost

Yes, almost like Macs vs the evil PCs.

Pierce

Re: FGV 40' with DD 6V92

Reply #19 – February 04, 2017, 03:22:50 pm

Rzrbrn, I have almost that identical coach, Not the special Edition, I have had NO problems, with the engine or transmission and have only had to do "normal" maintenance. I bought my coach with 30,000 miles on it in 2007 and have put about 29,000 mile on it driving around out beautiful country. The only problem I had was right after I purchased the coach, the belt that drives the hydraulic pump for the radiator fan system broke while I was driving from Ohio to Gettysburg, PA , the previous owner had an extra one in the spare parts drawer, I replaced the bad one and we were on our way. Expect to replace tires, batteries, possible alternator, the isolator system mounted behind the batteries, various solenoids, T.V.'s if they have not been updated. I love my coach and plan to hand it down to my adult children when I can no longer drive.. I would offer a lowball figure $ 15,000 to 20,000 and see where that gets you. P/M if you have any questions. Gerry

Re: FGV 40' with DD 6V92

Reply #20 – February 04, 2017, 03:46:44 pm

Because of the heavy coach and the gap between 3-4 on the 746 Allison Bird went to a five speed 700 series trans to eliminate the constant upshifting and downshifting in the hills. Aggravating

Re: FGV 40' with DD 6V92

Reply #21 – February 04, 2017, 04:05:28 pm

To clear the air of any lingering smoke, I have to say that I just love to argue. When my wife won't take it any longer and locks me outside, I argue with Koda. I would go with my business partner to a Gasthaus where we would drink and argue with the other patrons until it was light outside. Many times it got a little heated but it was always about a subject like cars or politics and never given or taken personally. Everyone was still friends the next day.

Agree with Gerry. Bought ours with 62,000 and now have reached the 100,000 mark with almost zero problems. Blew two hydraulic hoses, replaces a couple of airbags, solenoids, bulkhead fasteners and added solar to it but other than oil changes, the engine and tranny have been trouble free. I have never driven one that had a problem so didn't expect one here. You never know when snake eyes comes up but taking time to get acquainted with potential model problems and changing fluids goes a long way toward trouble free trips.

Pierce

Re: FGV 40' with DD 6V92

Reply #22 – February 04, 2017, 04:26:50 pm

I really appreciate all the comments. Gerry, glad to see someone has a similar coach. I live in TN. My 2 boys live in CA, so we spend a lot of time out west, one reason I wanted a 36'. We have been trying to stay in NP's and SP's. I hope with a 40 will will be able to continue to do so. I will see what the wife says and if we go see I will update here. My carport is exactly 11' high. Guess I will start looking for another builder to put a taller one up....

Re: FGV 40' with DD 6V92

Reply #23 – February 04, 2017, 04:50:55 pm

Lunker, thanks for checking the vin# and finding the previous sale in 2010.

Curious thing; the pics for the 2010 sale are the same pics the current owner used for this 2017 offer. I will go see the coach next week. It will be interesting to see if the coach looks the same as it did in 2010. Wonder why he did not post updated, and more pics.

Re: FGV 40' with DD 6V92

Reply #24 – February 04, 2017, 05:03:13 pm

I have a 91 U300 with a 6V92TA and 4 speed and it does just fine. Yes it stays in the right hand lane on big hills. Mine is only 300 HP ,But out on the highway on semi flat 70 mph all day long. I usually run at 1725 RPM which is about 65 and so far my fuel milage using actual miles and gallons put in is at 8.3. The ECM when I connected my prolink said lifetime mileage average 8.4 thats pretty darn close.
Yes OEM rebuild parts might be hard to locate ,But there are plenty of Top Quality aftermarket engine overhaul kits available, Interstate McBee,ect, and they have warranties as good as the OEM components. The reality for me is This engine should go a half million miles or so. I'll never wear it out as I just don't have that much time and the finances to do it. Be aware that the engine oil has to be straight 40 wt low ash content, I use Delo 100 40Wt and you will not find it out on the road at fuel stops or at the big oil change places like Speedco. You will have to order it and carry it with you. Not a big issue. And the best part it's just
Cooler Than Hell!
http://www.youtube.com/watch?v=IN0DtywsSW4

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