Foretravel Owners' Forum

Looking at an 87' GV, non-unihome with Detroit Diesel 6V92. It's pretty cheap! But I don't want that engine. Was thinking of an engine swap. Has anyone here done that? Are there pre-existing provisions in the structure of the chassis to install a variety of engines? Or am I thinking WAY outside the box? Thx!
Mikeado1

Curious as to why you do not want that engine? Is there an issue?

Any project is do-able if you throw sufficient money in the pot.  I can't recall seeing any mention on this Forum of successful engine swaps.

IMO, a properly maintained DD 6V92 is an excellent engine.

Overheated, using wrong oil, etc can certainly kill them.  So, their "care and feeding" is important.

LOL!!!!  I AM thinking way outside the box!!! Thanks for the input ya'll !

Found it on the internet. It's about a 7 hour drive to get there. Don't wanna waste my time driving there only to find that the engine is completely toast. But if I could take possession of it and then do an engine swap, I might consider it. The coach appears to be in great shape.

It is a full-rail Oshkosh chassis, so I assumed that the chassis was delivered to Foretravel with pre-punched holes in the frame rails, to which Foretravel made accomodations to attach an engine. Am I wrong in that assumption? I've not had opportunity to actually view an Oshkosh chassis in a Grand Villa yet.

Was really attracted to the rig initially, until the current owner made reference to the engine overheating a couple times on his most recent trip. Rig has 180K miles on it. He "did a top overhaul" on it 7K miles ago with no records of the rebuild, which leads me to believe he did it himself. Which makes me wonder how long it would last. And what if there's a crack in the block and he missed it on the top rebuild? There are reports on the internet of that happening.

There's lots of mention on the internet about the DD's overheating and blowing head gaskets and needing heads replaced/rebuilt. I could overhaul the engine myself if I had to but haven't the desire to do so.

It's not that I have something against the 6V92! They have a lot of great attributes. They're actually quite simple. I really do like the fact that the engine can be rebuilt while still installed in the coach! That's handy!!!

It's just that, in reading a lot of internet posts, it seems that the DD owners are constantly anxious that their engine is gonna overheat. Kinda takes the fun out of it for me.

The coach appears to be in nice shape and as I said, it's CHEAP. So, I thought en engine swap might be an option.

I'm an open-minded guy. Maybe I should reconsider!

What's the highest mileage GV with DD 6V92 installed? Whats the cost of a rebuild?

Thanks again ya'll!

Mikeado1

Check again for exactly which Detroit Diesel engine it has.

With an Oshkosh chassis, more likely to be the 8.2 liter 4 stroke engine.  A picture will tell you in a heartbeat!

As I recall, the 8.2 liter is 210 HP vs the 6V92 with 300-350.

When Foretravel buys the chassis the engine is installed. They are not in the business of building the Oshkosh chassis.

The best engine then and the best engine now. Excellent economy, bulletproof, low EGTs so no dropped valves, super reliable ECU, excellent injector wiring, no stripped threads on the pan, modern exhaust manifolds that don't look like they were made in the 1800, no intercooler to crack and develop leaks (aftercooler under the blower). and if you are lucky, a Jake on the later Detroits. 3 million built and they are still making them. 

If you recall, there are even a lot of 5.9s that can't be cooled. Some members have aux radiators installed in the nose on GVs. The side radiator was terribly done but the older models had the rear radiator and not prone to overheating. The EGTs are so cool that Detroits don't need to have an oil spray for the pistons. No CAPS injection pump to fail and cost thousands. Dead smooth at all RPMs and a smooth no shake 600 RPM idle whether just started or hot.  Did I say no dropped valves???

Foretravel is responsible for the overheating with zero time aligning the pump and tensioner so many Detroits lose a belt and overheat. Many don't see the warning lights as the steering wheel rim is in the way. The DDEC shuts the engine down but some have used the override switch and fry the engine. Anyone with even the least DIY ability can align the pulleys like I did. It's not rocket science. I aligned ours after losing the belt on the way home from the East Coast and have the same belt today and even the OEM tensioner.

The 6-71 found in boats, Greyhounds is known to be the most reliable diesel ever made. Some of the famous Duce 2-71 generators have never even been overhauled since 1950. When I bought my 4107 ex Greyhound, it was advertised with a new engine. It had 117K but the bus company owner laughed and said that was the same as new.

I've driven two cycle Detroits since 1967 without any problems in the fire service, in my bus and now in our U300. That was the reason I wanted a Foretravel or would have gone with a Wanderlodge, Prevost, Eagle, Dina, etc, etc.

Anyone with a side radiator and the Rube Goldberg combination of belt, pump, motors has to be anxious. I'm anxious each time I think about it and how it can strand us in some remote destination. Still going to install electric fans for a backup so I can drive at lower speed.

You don't even have to be much of a mechanic to work on them. No fabled "rack to run" like the mechanical engine. As Jerry M posted, anyone can do an inframe in the barn.

There is a big reason that Mercedes now makes Detroits and supplies parts throughout the world. Best thing for anyone to do would be to dump the Allison and swap in a Detroit DT12 transmission to come out of the stone age.

So, adjust the tensioner/pump alignment if you have a side radiator, use the correct oil for the engine, take the heater out of the thermostat housing and install a real block heater where 99% of Detroits have them. In the block where they belong. Then you are home free.

Pierce

I kinda went through this when I rebuilt our kitty cat 3126.
Bruce Bean said they didn't build the coaches around the motor so other motors would work, which made me think.
But the more I researched it, the more I realized so many things would be different starting with adapting transmission. Converter stahl would probably be wrong. Wrong rear end gearing, making wiring work ( gauges etc.). Would be easier on a non electronic engine.
I have seen many FT's in the past, converted from the 460 Ford to a diesel.
It's not like throwing a Olds engine in a 55 Chevy!
In the end, I rebuilt the Cat, and at 17K miles, very happy we went that route.
Chris

10 Best and Worst Diesel Engines in History - Capital Reman Exchange (https://www.capitalremanexchange.com/best-diesel-engine-list/)

So, while you quote one small shop, how about one of the largest and most successful companies in the world? They even invented the car back in the 1800's and are for the last decade, the F1 world champions. You have probably flown in an airliner with one of their Rolls Royce jet engines. Naturally, I'm speaking about Mercedes Benz (MTU) Here is their take on their Detroit 2 cycles: 2-Cycle Service Products (https://www.mtu-solutions.com/na/en/service/2-cycle-service-products.html)

You probably know that Cummins is now making one of the most advanced 2 cycles today, CAT has controlling interest in EMD, the maker of 2 cycle locomotive engines and the biggest ships at sea are 2 cycle powered.
The 60 series while they were great, have been out of production for many years. Mercedes took many of their outstanding features and incorporated them into the DD13, 15 and 16 and is producing the DT-12, an automatic clutch, manual transmission with GPS controlled grade profiles and automated shifting.

Why do you think every bus company in the world has made the Detroit 2 cycle the mainstay of their fleet in the past? Smog killed them like CATs. But almost the same engine only larger (EMD ex General Motors) powers a big percentage of the railroad locomotives today with their 2 cycle. The 92 series is still being sold for on and off road vehicle applications, generators, boats most everywhere in the world today.

Pierce

I wouldn't bother going to the problem of changing that engine. 2 cycle engines
are great engines.

Last in frame kit I bought was ~$ 2500 for a 6v92.

Mike

Several years ago we had an in-frame overhaul done on our 6V92TA. At that time someone commented that we could fit an 8V92 in there. I mentioned that to the lead mechanic on our job, and his response was, "Do you want to see a grown man cry?"

As was mentioned above, you can make almost anything fly if you throw enough money at it. Just ask Congress.

Find a coach you like how it is made and buy it, not buy something you don't like...

I would still like confirmation that the ORED he is looking at has a DD 6V92.  If DD 8.2 much of the discussion is moot.

87may have been built in 86 and could be either the 2 stroke or the Fuel pincher 4 stroke. 
  If its cheap and runs,drive it home and make an assessment.
  At that age the engine will be the least of your worries. IMHO.

So what engine do you want to swap in? Probably have to buy a donor coach. Just fix it, the donor. And in three months you can be using, says the man with too many projects. Lol save your sanity, if your looking keep looking a good one is out there. That's what I did and it still has been a full time career and was what I wanted
Scott

I had a 6V92 in a 40' PT40 Wanderlodge, didn't use it at all as it needed redone and sold it for a loss.  That being said. the engine ran awesome, plenty of power and sounded great in my opinion.  Make sure you buy what you want, especially engine wise, seems like it'd be a pain in backside to swap engine.  I now have what I believe my ideal coach, a 1988 31' Barth. Spartan Chassis, Cummins, Allison, and 22.5 tires.  Just wait till you find your coach, you'll know.  Foretravel Forum, and Barthmobile, Wanderlodge Owners Group are AWSOME to help with any problems or questions, which I will always stay with one of these brands. Blessings and good luck!!

Spot on info IMO
I spent a year looking and basically disqualifying everything I could till I narrowed it down to our current coach. I actually had basically given up on finding what I wanted. Do you plan to tow over 5k? If you do this will deleat most coaches including your engine swap regardless on what engine you put in. Can't change the GCWR. even if you have 600hp. This forum found it for me.
Scott

Overhearing can easily be caused by oil and debris built up in the radiator fins which can be cleaned out using something like Simple Green.
You can check for oil and dirt build-up with a plastic straw.

Okay guys, apparently I heard wrong.

It's a 1989, small basement, Oshkosh chassis. And has 8.2(Fuel Pincher?)! Information is coming from the current owner. I have not physically put eyes on the rig yet. Coach looks in great shape in the photos. Now, what do ya' think? Engine swap still sounds fun to me. But I'm a sucker for a good project also!  :D

 Sorry for the confusion!!!!!!!!  Mike

I don't know the footprint of other engines compared with the 8.2 but you could certainly check.

The other critical factor that could limit your choices is the transmission's HP/torque limit-- unless, of course you are looking for a complete drivetrain transplant.

Also, be sure to consider the cooling capacity/heat rejection.

OK, here I am. I own a 1989 GV with the 8.2 DD turbo charged V8 engine and four speed Allison tranny.
A few things I would like to point out.
The chassis is a V-815-2 and the Allison four speed is an AT-545 NOT the V-917 chassis and the MT-643 tranny. The V-917  and the MT-943 were used with the Cat engines due to greater weight, more horsepower, and greater torque.
The chassis is a rear radiator model, and if anything like mine, has a louvered door on the driver's side near the back end of the coach that provides access for water and electrical hook
The brakes are most likely drum brakes. (less stopping power than disc brakes)
Any engine longer than the 8.2 means the foot of the bed will have to be shifted forward which means the loss of the small walkaround( walking around the foot of the bed and up both sides.)
Better check CCCP of the V-815-2. A bigger, heavier engine might put you over the top of spec. Not a big deal? Yes it is! Wheel bearing capacity, handling ability, axle rating, and leaf spring load limits.
OK, now about the overheating issue. I swapped the original steel fan for a newer nylon one. I also religiously check that I can see light thru the rear radiator. So we have not had an overheating issue in the almost ten years we have owned our coach.       
TOWING: We tow a 2006 Saturn Vue AWD. It is at the upper limit of what is specified for towing, but it is what we have. So we know we are not driving a Greyhound bus.
If you go to a bigger, more powerful engine I recommend/suggest you change the brakes, the rear axle to a heavier unit, the leaf springs, and the tranny to a more robust one, and you had best take a really good look at what would be involved with converting from a rear radiator to a side radiator. This would involve losing the standing access to the driver's side of the bed.
Last two but not least-- try to contact James Holder  in Tennessee. James has two GVs and is the Service Manager.  I have his contact info if interested.
One more thing...Daimler now has ALL the info on the Oshkosh chassis's. I have that contact info also.                                                                                                                                                                                                                   

We have looked at this for swapping prior .  Do a search maybe
 Issues are the trans mostly . Viable swaps are the smaller TD engines and trans , like maybe the Duramax , Ford 7.3 ,  Isuzu? ect. 
 Best bet is to run it carefully  and fix the stuff that needs fixing.  The engine may run perfect for a long while .

The 8.2 is a high RPM diesel and unless another of the same is installed, you are going to have to replace the third member in the rear end. Replacing the ring and pinion is going to be way more expensive and not that many people can do it right with all the preloads, mesh pattern adjustments.

I installed a 7.3 turbo in our SOB many years ago. It was a mechanical engine so only 6 wires total for the swap. The glow plug timer was even mounted on the engine. I dumped the auto for a Getrag 5 speed manual with O/D. Doubled the fuel mileage over the 440 Dodge.

So, it is possible but lots of little problems come up that you never thought about. Engine mounts, throttle linkage, air cleaner, oil pan modification is necessary in a front engine coach, exhaust system.

With a Foretravel, unless you have lots of time and tools, including a welder, metal cutting band saw, etc, it's always better to just buy the coach/engine combination that you wanted originally. If you go to an electronic engine, be prepared for a LOT more work getting it working right.

Pierce

On my 8.2, 2,500 RPM is pretty much getting up there.
On my tach the needle goes horizontal at the three o'clock position and by then, on level ground I would be doing around 68. Not comfortable speed for us.
Before I removed the oil drum muffler I could not get the engine to rev that high.

Right. Most likely about a 4:10 gear .  Any modern engine/trans combo  will be fine with the rear gear.  All of the newer stuff can run at 3000 RPM easy and the trans have enough range to find a happy cruise gear.

I think the most popular engine in most RVs today is the Cummins 8.3 liter engine. Popular many years ago and today too. The fuel cutoff is at 2400 rpm, a long ways from 3000. We have a 3.07 rear end (no OD 5th or 6th) but we turn only 2130 at fuel cutoff. I don't know of any big diesel that will happily turn 3K.

I don't think we are talking about repowering a newer Foretravel but as a viable alternative replacement engine for one of the older engines Foretravel offered in the late 1980's and early 1990's

Pierce

Why would anyone NOT want that 2-stroke diesel?  It sounds like a V-12!  And with the electronic fuel injection you needn't concern yourself with the classic Detroit Diesel tricks.

OP has identified that the coach he is considering has a DD 8.2 liter 4 stroke.  Totally unrelated to the 2 stroke DD's.

A good diesel and like the 6.9/7.3 Ford/Intn., with the upgrades to cylinder head bolts, should provide good service with any earlier problems behind them.  Some injector timing tools are supposed to be difficult to find but there are many thousands of these engines in school buses, trucks, etc. They are known for giving excellent fuel mileage.

When I was driving my damaged donor Ford PU with the turbo 7.3 in it back from St. Paul, MN, i was talking to a guy at a rest stop with a new PU. He had just sold his 6.9 Ford PU with 650,000 original miles on it pulling horse trailers. Never any trouble so it does not have to be a big rig CAT, Cummins or Detroit to give reliable service. Same with the 3208 CATs.

Pierce

I hinted that disc brakes are better at stopping than drum brakes and was questioned about that statement.
Well, I guess I was basing my statement on the fact that drum brakes are not as popular as they were, for some reason.
And there must have been some basis for the popularity of disc brakes today.

Disk brake will take the heat better better than drum brakes. I have found that
the drum brakes on the Monaco I had stopped better then the disk brakes on
my Foretravel.

My bad.  I *thought* the OP mentioned the CAT fuel pincher, but I scrolled back to the beginning to double check the engine and the wheels fell off the bus.