Hello ,
I have always thought it would be cool to convert it to diesel basically because of fuel mileage. My 454 is fine but at 6-8 mpg it doesn't get used much. My thought was to go with a Cummins because I know the one a used to pull a 5th years ago would get 18 mpg with a 5sp. I new I would never do it because of the cost of the conversion in a 35 year old motor home.
I came across this http://greenville.craigslist.org/pts/3775255465.html last night and it peaked my interest. The problems with it is they cut all the wiring, it has no ECM and the transmission is for a 4WD. If it wasn't for those things is looks like it just bolt in.
He says is came from an H1 hummer and I understand those are more heavy duty than the regular GM units, is this true? What kind of fuel mileage should I expect from one of these in an old P30 with 4.10 gears?

Neil.

I thought about the same swap. I think 11-12 mpg would be about max. You won't have the power of the 454. Cooling may be a problem. Will be more noise. Will need heaver front springs. Gen set will need separate fuel tank or propane conv. Fuel 10-20% more. Take pictures and keep us posted.

If I were considering this swap in a P30 something, I would not consider the 5.9L Cummins or GM 6.5L. The 5.9L is a tall engine and would be difficult to do in a front engine location. The 6.5L GM engine has a spotty reputation. The Duramax IMHO would be the only logical choice. The reliability has greatly improved and parts are easy to source. It also it a much quieter engine (than the 5.9L or 6.5L)do to revisions in the combustion chamber. A bit bigger than the 454 and oil pan considerations needed but overall would be a much easier conversion.

How many hundreds of thousands of miles would one have to drive, saving a penny or two on fuel to break even on the cost of such a conversion? The P-30 sumthin is a natural for the 454, live with it or buy a D pusher. Just saying.

quote:

Originally posted by MWrench:
If I were considering this swap in a P30 something, I would not consider the 5.9L Cummins or GM 6.5L. The 5.9L is a tall engine and would be difficult to do in a front engine location. The 6.5L GM engine has a spotty reputation. The Duramax IMHO would be the only logical choice. The reliability has greatly improved and parts are easy to source. It also it a much quieter engine (than the 5.9L or 6.5L)do to revisions in the combustion chamber. A bit bigger than the 454 and oil pan considerations needed but overall would be a much easier conversion.

I looked into it in around 2001, and even talked to a couple of Workhorse engineers about it. They said they were working on a Duramax P30 chassis, but the project was dropped because GM was selling all the Duramax trucks they could get engines for.

They said they had been designing a new cross member. Don't remember the particulars any more, but it was pretty straightforward. The crossmember supports the front suspension, so only the center section of the crossmember would have to be cut out and replaced to support the engine and clear the sump.

At that time, I couldn't find a donor vehicle, so I dropped the idea and put in a 502. It has been great, but a Duramax was my first choice. Still would be, in fact.

The 6.5L with 18:1 pistons is quite durable. There was little improvement by GM for the Hummer engines (in fact, some later blocks were weakened).

If you want a project, I have the engine removed from my Barth (some assembly required. The heads have been checked for true and magnafluxed and the turbo was tested. A set of gaskets is included. It has the dual thermostat an high flow coolant pump.

It will need a rebuild as 4 of the cylinders are slightly scored, a common issue with early 6.5s. The lower end should be OK, but make no mistake, this is a project short block, no tensioner, no P/S, no alternator, no A/C compressor, and brackets for none of those.

Note that conversion to diesel could require major rework of the power brake system, but the 6.5L is a drop-in fit.

Price: Free - U pick up

I never was set on it, I just wanted to put it out there for discussion. I was waiting for Rusty and Bill to comment because I know they both had re-powered there Barth P30 but went different ways. After thinking about it a while I decided was not a good idea. One of the reasons I bought the Barth was because it had the simple Chevy drive train that was cheap to fix and easy to find parts. I dont think this 6.5 fit either of those. If it had been an earlier version of the 6.5 with no electronics and a 2wd transmission like my old 93 GMC had I may have done it. A Duramax would be the best choice if money was not an object but if that was the case I would get a Diesel pusher. When the kids are out of college I may be trading up to a diesel pushers from another barthmobiler when they are done with it. I still think a early mechanical Cummins 5.9 and 5sp would fit the bill but I doubt I would ever find a worthy candidate at the price to make it worth while. I think the 454 in mine will soon require 2+ grand in repairs to keep it dependable for another 5 plus years so I figured I would look for other options.

I just came across this on craigslist http://greenville.craigslist.org/pts/3692773303.html. What to you think, is got every upgrade I was thinking of, overdrive transmission, fuel injection, single belt pulley system.... But still probably only 7 MPG .
And this http://www.painlesswiring.com/...hp?SearchField=60216

Iam thinking about it.

Thanks.

Neil.