Cummins Diesel Upgrade to Classic MH

[outofcontrol]

I found this place in CO that specializes in putting those 4BTA cummins motors in Land Cruisers.
Proffitt's Cruisers
It's a different swap, but similar in a lot of ways. The reason I mention it here is that they have nice example invoice with a rundown of all the parts and some of the work neccessary. Example Invoice

I know that place in Montana charges about $15k to do a swap like this, and you have to supply the motor.

I think this quote sums it up for me:
"In general, overall fuel savings does not pay for itself with these conversions; most people convert for the unique aspects of the conversion and sometimes to run alternative fuels such as biodiesel fuel"

I think another thing to consider is the increased resale value of swapping to diesel. it seems like no matter the model, the diesels go for at least $10k more than the same unit with a gasser.

Not that I would ever sell my cherished MoHo

-Kevin

[swebster]

Kevin,
I don't think I'm looking for a short term ROI on this. Rather, my 454 is appraoching it's end in the coming years and rather than R&R another gasser (it's likely on it's third now), this seems like a better alternative for how we use the coach.

That invoice is great, but I noticed it included things like transmissions and tranny adapter plates and a new exhaust, battery, etc. There were certainly a lot of little things but I'm thinking having the donor vehicle might help to minimize the bits and pieces issue.

All in all they had about $3900 in labor for a conversion. Not as bad as I thought. I would only undertake this project as a DIY and would hope to cronicle it on my site for others.

[87MH]

Originally Posted by swebster

So no one has an issue with a 4 cyl diesel?

What about the generator - Diesel? Propane? Add a small gas tank - perhaps an outboard tank mounted someplace?

[swebster]

Yeah, LP or a second tank.

[outofcontrol]

Oh, I totally agree. I think a diesel is totally made for this application. And I wouldn't do it for the ROI, but more as a cherished improvement.

I would only do it as a DIY project too. It would be cool to see a list of all the needed parts and modifications when you started the project so you could plan your time, money, schedule, etc. And it would be great to use a complete donor vehicle for all the little things that you'll need, but didn't plan for. little brackets, connectors, and kind of "living diagram".

As for your donor vehicle, I think the 4cyl option is fine. The output numbers look suitable. There's 2 things that I would be weary of: 1. "there's no replacement for displacement" you could have a smaller motor with the same output, but it's going to stress and wear on the smaller block faster. 2. if it's too new, there's so much electronics, you might have some problems making it work. The whole dashboard might have to be put in the coach. I just know that some of the diesel conversions with newer motors get stuck when they get to the ECU and technical computer conversions.

the beauty of the older diesels is that they have 2 connections: fuel and 12V, that's it. and if you're a DIY guy, simple is better. it's a tough decision because the newer diesels are more efficient, powerful, and quiet.

All I know for sure is; if you do it, take tons of pictures, because you'll have a great audience.

-Kevin

[bkahler]

Originally Posted by swebster

So no one has an issue with a 4 cyl diesel?

I certainly don't, especially if its turbo charged

Since we got our 88 Ford F250 with the 7.3L N/A (non-turbo) diesel I've been impressed with the torque these engines have. I can't imagine what a more modern diesel would be like.

I'd say go for it.

Brad

[PeterKnop]

Has anyone ever put in an early bluebird schoolbus engine in a 345?
We are going to try to fit the 1990 straight 6 international diesel in our 89 345. Should not be too big with a lower motor mount, but I hadn't considered the extra weight. I think it will put an extra 500 lbs on the front axle. But should get 13-14 mpg and can use WVO and biodiesel, maybe more with a Gearvendors. We will do a rebuild on the engine before- new pistons and cylinders, seals, etc. But it will be great without any computer controls!
The GVWR of the bus is 22,500 so we should be able to pull just about anything, but not if we crack the front axle .
We are concerned about the noise, we don't want to wear aircraft headgear to talk w/o shouting, and we have dogs that could hear even more of the subsonic and ultrasonic noise. Would many layers of soundproofing and maybe some aluminum sheet make it about the same?
Thanks, Peter

[Kajtek1]

I am new to this forum, but not new to diesels.
Years ago I bought 1978 Pace Arrow 27' motorhome that PO converted to diesel. Even the 110HP Toro Flow (very old mechanics might remember) wasn't giving it very high top speed, but thank to second auxiliary transmission I could drive that thing where SUV failed.
Bad part was that the old engine didn't have good service records and when it blow up in Ottawa (over 2000 miles from home) the available replacements would stick above the dashboard.
So I had to abandon the motorhome and get another one 1/2 way into our vacations.
Didn't read whole topic, so sorry if I repeat somebody's findings, but here are main points with conversions:
-humongous amount of work involved
-older diesels can be bought cheap, but they are heavy, big, nosily and don't provide too much HP
-newer diesel engines are very nice. The Mercedes 320cdi produce 210HP and can be carried by 2 persons, but it has as much electronics components as mechanical ones. Good luck in dealing with them
-even if you pay the mechanic, or helper only $10/hr the labor involved in conversion will cost more, than newer factory build Diesel Pusher
So if you have good diesel laying around (I can buy Detroit 8V71 for $500) and have nothing better to do with you life, the results can be rewarding.
Did I mention humongous amount of work? But this is going to be labor of love.

[vette59jdwl]

Well gentelmen I have been reading these post quit diligently, and have a LARGE ??????Question is there anyone still reading these post and has anyone still have an interest in this.Also has anyone ever taken a body off of an ARGOSY or AIRSTREAM Motorhome. If so how does the body come off of the frame. I mean the whole thing not just the BODY. I mean Body Floor the whole nine yards. You see i havent gotten my new 1975 Argosy home yet so i cant measure and find out this information ,any would be app-reciated thanks wayne lave@distributel.net

[vette59jdwl]

Those school busses seem neat - how about a full chassis swap? Get a Bluebird or other cabover, section the chassis, and look what you'd have?
.school bussses have to be maintained to a certain level.....
Marc[/quote]
Marc I think your on the right track.I have been looking at the bluebird bus finally bought one with the 6 cyl cummings diesel with auto transmition.My plans are not for a classic but for a 24 foot argosy motorhom.I gave thought to everything and the gvw would be crazy so take the body off the 35 foot bus and cut it down to the exact size of the 24 foot motorhome. Only thing is i do not know at this time how the body of the argosy motorhome is attached to the frame any information would be thankful wayne

[Kajtek1]

School buses don't have storage bays and usually have city gearing, preventing from driving faster than 55 mph.
Those are important things.
Most of those construction is a cage welded together and than filled up with insulation and sidings.
Than each manufacturer has different methods.

[vette59jdwl]

The construction of the bus has nothing to do with what i am doing .The bus body will be scrapped. What i wish information for is How the Argosy/Airstream M/H body is attached to the frame.As far as BAY storage is concerned I dont feel this is a problem I have been down that road before,Only i went the other way I took a school BUS and cut the roof off raised the roof 9 inches and put the remains of a 22 foot airstream on top of the bus frame.We used this for a hunting and camping bus back in the boonies.This time i wish to build one for the wife and i to go south in so it cant look like a pig with perfume. After reading everything i could find here the P30 chassis just doesnt cut it when you use the word DIESEL.Oh yes and i intend to haul the 59 vette on a float behind the 24 foot motorhome

[vette59jdwl]

By the way I just got off the phone with the guy i purchased this 35 foot Bluebird flat front bus with automatic 5.9 diesel bus from and he informed me that this bus was a rural bus ran from a small village to two other small villages before taking the teenagers to the collage at a larger city He informed me that this bus would run 70 mph all day long so i dont think that is going to be a problem, and here i was thinking a two speed rear axle LOL LOL Wayner

[Kajtek1]

Congratulations.
Looks like beautiful start of 10-years project

[bkahler]

Originally Posted by vette59jdwl

Only thing is i do not know at this time how the body of the argosy motorhome is attached to the frame any information would be thankful wayne

I definitely don't have the answer to your question above but I do have some observations from laying underneath our two Airstream motorhomes and working on our Excella trailer.

In all cases I think Airstream laid down a sheet of aluminum on top of the frame and then laid a sheet of 5/8" wafer or flake board on top of it. This would have been a full length piece with no cuts or seams. They may have laminated the aluminum sheet to the wafer board first but however they did it the first thing is a sheet of aluminum and then a sheet of wafer board.

From there they set the assembled shell down onto the frame and bolted the aluminum shell into place. They then started the assembly process inside the motorhome.

Personally I think it is possible to remove the entire structure (shell & floor) as one assembly but the process would be time consuming and tedious. I think what you would need to do is park the motorhome in your shop on a nice flat paved surface. Raise the motorhome up on jack stands so that it is something like 18" off the floor.

You'll need to carefully look around the entire underside looking for points where the shell/floor is fastened to the frame. You'll then need to remove ALL of those fasteners.

At this point you would have to start setting up all kinds of posts/pillars in various places under the motorhome. Basically any open area where you can support the floor of the motorhome with a post or pillar would be needed. Once you've accomplished this you could lower the chassis back to the ground. Now you're going to have to set up a series of supports arrayed around the outside of the motorhome with beams running side to side under the shell. You would want these beams to be resting on the underside of the shell so when you removed all of the post/pillars the shell won't move. After the support beams are in place and you've removed all of the posts/pillars you should be able to roll the chassis out from under the motorhome.

I'm not saying this would work but its how I've considered doing it for our motorhomes if the need ever arises.

This is all pure speculation but who knows, it might work

Keep us posted as to your progress and methods.

Brad

[Wayne Olson]

I have had the entire insides taken out of a 345 as well as all interior wall aluminum so that I could rewire and restore (2 year project). I believe you would have to do the same in order to get to all the bolts, screws, etc. that hold the flooring to the frame. All of the interior was put in after the shell was put on the frame. I do not even want to think about what it would take for just the dash wiring. Good luck with your labor of love.

[choctawmel]

Looking at my 'Silver Bullet': The floor is nailed (Just removed the carpet. Would of thought they'd used bolts or screws, but looks like nails) to the tubular frame and the frame is riveted to the P-30 rails.
Wouldn't be like taking the body of my '61 VW for sure. But then maybe just like it only big, BIG, BIGGER.
mel

[Kajtek1]

I was in vette shoes 5 years ago. I am mechanic turn into house remodeler, so can't imagine person better qualify for such a job. But I am also, or rather I am not a dreamer. The market is flooded with RV conversion projects "almost finish" that sell for for pennies. One city 40' bus had impressive blog on the net. The guy stripped all the city decals, ordered factory sheeting to cover second door, build custom sofas to cover wheel wells, corian, high end floor. The motorhome was already functional, when he fell in love with interstate bus having storage bays and highway gearing. Long story short, the 95 percent done custom conversion generated about 5 grands on the ebay. I was shopping around till I run into old conversion parked somewhere in CA woods. I started with stainless steel exterior and bulletproof engine. Just replacing rotten sofas, brake chambers, holding tanks and some upgrades to electrical system turned out to be 6 months full time job and the project never ends.
So be realistic.

[choctawmel]

Kajtek1, I really wanted to do a MC-5, GM 4106, or GM silverside bus when I was younger and dumber. Looked at a bunch of them, most in the project stage. Only one I'd of driven home was a 'cherry' Sivlerside, but it got sold while I was looking at it. Then I found my AS and decided a bus conversion wasn't on my bucket list. Still would like to put a diesel in my 'Silver Bullet' but I'm trying to shorten my list. So, I'll cross that bridge when the 454 is closer to it's end.

[Wayne Olson]

I have also done several "Should be Easy" RV projects. Then when you get started there are always many things you did not think of when you started that have to be done before you can continue with your intended project.