Cummins Diesel Upgrade to Classic MH

[Silvertwinkie]

Aw heck, why not just drop in an LS7? Fuel economy might be close to that of the diesel. A well maintained gasser could last 20 or more years too. An LS7 has 505hp and 470ft/lbs....and it won't take hours to get to speed either....

In all seriousness, outside of a MH application, I have been kickin' around the idea of putting the LS7 into my Suburban. Most likley won't do it, but can you for even a second, imagine an LS7 powered Burb?

[3Ms75Argosy]

Steven - I dunno. I've been there with swaps... gas to gas. the mechanical bits are the hardest.... is this electronicly controlled? I suppose the motor mounts wouldn't be so hard to fab, it's tying the whole ball of wax together that's the hard bit.

I don't think you'd miss too much power (other AS have the Izuzu, no?)... but some of those box trucks have been put away HARD...... Cheap at first may not be so later....

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?

Or gut their motors....school bussses have to be maintained to a certain level.....

You definately use your mh alot, I'm sure you might see some upside to a swap. I'd love to put a cummins in my Dodge 1 ton van. Then it'd be closer to what I need.

Marc

[swebster]

The donor is a complete 2000 truck, everything works and has been well maintained (I know the owner). It's a refer and the box is worth the price of the truck. Hard to think about a 4 banger in there but it's a modern turbo intercooled electronic everything. I could gut the truck and get everything from one place.

I also noticed some of these box trucks came with 5.7's in them (the gas version) so the mounting question seems somewhat easier to me after learning that.

[fastrob]

Having the tools, all the parts, the skills, the patience, available space and time is quite a feat.
Do you have all these things? Or at least enough drive to compensate for not enough of any other?
If so I wish I was close enough to offer a hand.
Do you have the moral support from "She who Must Be Obeyed"?
How many miles on the motor and transmission?

R

[Coastalview]

Steven, the Isuzu 4HE1TC turbocharged engine with direct injection is rated at 175 gross hp at 2700 rpm, with 347 lb.ft. gross torque at 2000 rpm. Is this really enough to move a 345 down the highway even though the GVW of the donor truck is 14,500?
I think this engine is more suited for a metropolitan enviroment.
Jeff

[swebster]

Less hp than the 454 but my specs show 358 ft lbs which is more torque than my 454 and at 1000 rpms less.

The engine comes in N series trucks to 17,500 lbs. My 345, fully loaded has a gross of 16,5000 lbs.

Rob - Yes, I have the time, place, tools and the like. The coach already has 200,000 + miles on it (my 345 that is).

[fastrob]

Originally Posted by swebster

................................................
The coach already has 200,000 + miles on it (my 345 that is).

I did a transmission swap without replacing the clutch. Guess what? The clutch went.
I did what I call poor economy and it cost me the cost of the labor to pull the transaxle and replace it and the clutch. My rambling is leading to ask the question the soundness of the motor and transmission is all.

R

[3Ms75Argosy]

I guess my only thought is how hard would it be to add modern electronics to your older MH. Speedometer for example. I think the computer would take it's readings off the tranny, but harness issues could be a factor.

How hard will it be to cool that intercooled turbo?
Marc

[swebster]

Well....I need to investigate the donor powertrain. I do know it's been well maintained and it was purchased new by the owners. On things like the speedo and gauges...well the donor has all of them so perhaps they swap too. The dash of a 345 is a big flat metal plate with pretty lousey guages in it already. One of the things I like about a donor swap is that all of these little things are there and usable and already work in the donor so moving them over too is a possibility. I also like that I can drive the donor around, get a feel for the power (or lack of) and understand all of the systems before a swap. Seems better than buying a rebuilt or takout engine from a yard and then having to figure everything out.

I also need to find out what the engine/tranny weight as Dennis pointed out the P30 is limited in what it can hold up. Right now this is all just spit balling. I do like the idea of a four cylinder TD 345.....I would certainly have a very unique forum signature

[guy99]

Regarding the front suspension, when I had Henderson Line-up (manufacturer of the Super Steer products) go through my front end they replaced my front coil springs with and did away with the airbags. I'm sure you could replace your springs to handle additional weight.

[swebster]

Guy...I wondered about that. My coils are tired now and need replacement. That would be the utlimate. I do wonder about the bearings and spindles and a arms with any significant weight addition but I don't know what the Isuzu weighs yet. I might even be lighter.

[3Ms75Argosy]

Hey, how about splicing the new frame with the old frame (just the front end) and make it an "easy" swap? The box truck is a cab over, right? Wouldn't the steering linkage work about the same?
Marc

[swebster]

It's a cab over. I dunno...seems like more work than fabing some mounts.

[3Ms75Argosy]

I think we'll be seeing more threads about the swap! Go for it!
Marc

[swebster]

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

[3Ms75Argosy]

well, smaller - but torque a plenty. I don't think you'll beat any gassers from a stoplight, but you will cruise fine and get better mileage too. I was reading up on the new medium duty Kenworth hybrids. Our local lumberyard was the first customer. It's a big truck with "only" 245 HP. Lot's a torque though.

I think you'd be fine with a 4 cylinder. One thought I had was integrating your steering gear and the new steering pump on the donor engine. Are the psi compatable?

Have you compared sizes of the two powerplants?
Marc

[guy99]

Originally Posted by swebster

Guy...I wondered about that. My coils are tired now and need replacement. That would be the utlimate. I do wonder about the bearings and spindles and a arms with any significant weight addition but I don't know what the Isuzu weighs yet. I might even be lighter.

I'm sure the guys at Henderson know the specs on these parts and would be happy to let you know if you would be overloading these components. When you know what your approximate new front axle weight will be, give them a call, or, if you like, I'll call them.

[swebster]

Thanks guys. I don't really need to beat anyone off the line. I'm one of those slow pokes in the motorhome anyway. I typically only travel between 55 and 60 mph and quite honestly I enjoy it. It's a motorhome....I get my speed fix on my road bike.

The isuzu is small compared to a Cummins, 454, etc. I'll take some measurement and pics soon. I'll also try and get the weights.

[wascobob]

swebster---Have you thought about looking into the Cummins 4bt, the little brother to the 6bt. I hear that they can be hotrodded to make good horsepower and torque. They are also made to mate with the Chevy bellhousing and the P-30 chassis. There are many in sevice in delivery type vans. Just a thought!
---------Bob-----

[cooperhawk]

Originally Posted by guy99

I'm sure the guys at Henderson know the specs on these parts and would be happy to let you know if you would be overloading these components.

Well, keep in mind that coaches like ours already have the 6BD1 installed and I believe our front ends are similar. The 6BD1 is heavier I'm sure.