We have a 79 24ft barth and are planning a complete top to bottom renovation. The plans are in place except for one major item. I am considering replacing the 454 engine with a 6.6 diesel w/6 speed allison. I know this will be costly but this will be our dream motorhome. My reasoning for this is that we will have more power and better milage. There is nothing wrong with the 454 and it only has 20000 miles on it.
I know we have some very knowedgable people on this site and I would appreciate any input, pro or con.
Thanks
Ed

quote:

Originally posted by Lovestogo:
We have a 79 24ft barth and are planning a complete top to bottom renovation. The plans are in place except for one major item. I am considering replacing the 454 engine with a 6.6 diesel w/6 speed allison. I know this will be costly but this will be our dream motorhome. My reasoning for this is that we will have more power and better mileage. There is nothing wrong with the 454 and it only has 20000 miles on it.
I know we have some very knowledgeable people on this site and I would appreciate any input, pro or con.
Thanks
Ed

I considered the Duramax. At the time, it was new on the market, and there were no donor vehicles available. You would need a donor vehicle to be sure you got all the stuff necessary.

The Duramax in a P30 requires major crossmember engineering and probably a different rear end ratio. I spoke with an engineer from Workhorse shortly after the DM came out, and he said they were considering it, but the engines were in such demand that the project was on hold. He did say that it would be a major undertaking, requiring a new crossmember, I believe. Take a look at the pictures of the engine. I am an engine swapper from way back, and really wanted a DM in my Barth.

It would not be too big a deal to get out a cutting torch or plasma cutter and an arc welder to remove the center of the crossmember for clearance and then weld up new structure. I would suggest either doing in in situ or, better yet, construct a jig to prevent distortion before doing any cutting. The crossmember mounts with six bolts on each side. This would be time consuming but cheap for you to do yourself, but expensive to pay a good welder/fabricator. I did a similar thing on a 4WD center crossmember to gain ground clearance, and it was a lot of work. But it was a good excuse to buy a plasma cutter.

It would be a very nice combination, but I am not sure about the cost/benefit ratio. Have you worked out a budget? Time and money? If I had a magic wand or Leno's money, I would do it in a heartbeat. Some of the cost/benefit analysis depends on how many miles you drive. The more miles you drive, the more a diesel will save you in fuel.

My own answer was to put in a crate ht502. It has more power and about the same torque as a Duramax, and drops right in. Well, lifts right in.

However, with a low mileage 454 and a fairly light Barth, you could just breathe on it a little for a lot more power. Thorleys, a Performer or Weiand manifold, custom carb and advance curve work, cold air intake, and even a cam would do it. A 24 footer is light enough that a Gear Vendors overdrive would likely improve mileage a little, and second overdrive is very useful for climbing

I'm with El Segundo Bill on this one. Absent Leno's money, & a burning desire to spend big bucks for bragging rights, I'd do the interior & exterior to suit myself, warm up the 454, & add a Gear Vendors as Bill suggests, then drive it until I got used to it, or the desire for a diesel became overpowering.

Figure out how many $ you'd save at a 25% increase in economy w/diesel, compare it to the $, time, & hassle factor of the conversion, & take it from there.

Think of the enjoyment you'll have daydreaming about the diesel while you already bask under sunny skies in your Super-454 powered Barth that can out-dig, & out-climb any other gas (and most diesel) powered coaches on the road.

"There is nothing wrong with the 454 and it only has 20000 miles on it."

The most knowledgeable gents on this site, bill h & Olroy, agree; I'd take their advice.
I don't know how long it's been since you've been caught in the throes of an engine exchange, but think back to the point where IT DOESN'T QUITE FIT... and the gloom sets in.
Also, it's unlikely the cost is justified. Personally: I'd spend the newenginemoney on a killer paint job.

Apparently, there are now Duramax engines surplus to GM's needs (there's talk that new-production Humvees will have it instead of the 6.5L).

But I'm in line with the others - if it works, don't fix it. And you may find a need to redo the front suspension to handle the added weight of the diesel and the Allison. The headers, manifold, and Gear Vendors OD would do most of what you want.

There was an FMC 29' pusher converted from a Chrysler 440 to a Duramax - the cost, the seller claimed, was about $20K.

quote:

Originally posted by Lovestogo:
I am considering replacing the 454 engine with a 6.6 diesel w/6 speed allison. Ed

The 6.5 would be an easier conversion. At one time, new engines were available at a reasonable price. May still be. It is not the engine the Duramax is, but you would have diesel economy.

If you choose the Duramax stay away from the earier (mid 2004) engines. I own a 2003 GMC service truck w/ 107k miles and it's now on it's 4th set of replacement injectors.

The earlier Duramax engines have the injector under the valve cover and are prone to early failure.

The mid 04's to current production engines have a newer style head and relocated injectors. These engines report very few problems with the injectors.

GM has made good on all of the injector swaps and has even extended there warranty because of this.

I too, would love to do the Duramax, but my 454 is just too good. I've got Thorleys, Nology Hot Wires and a Gear Vendors and have all the power I want. You would be surprised the grade that the 454 will pull even with 4th OD engaged. And as long as I keep it at 60mph, I get 10/11 mpg. This is a 28' 1985 Regal, about 15500 loaded, with the stock carb and distributor. I'd rather get it painted.

What a great group!!!
Thanks for all your advice. When we bought the Barth 4 years ago, it was with the idea of bringing back to its former glory and then some. We plan to completely gut the interior, rewire, replumb,foam insulate, build and install all new cabinetry and furniture to accomodate a new layout better suited to our needs and wants. My business has kept me too busy to give this project the time it will take to properly complete. I am glad for this , however, as it has taken this long to formulate the correct layout. I am on the Barthmobile site daily and have learned much from it. I feel as though I know some of you guys personally which is why I asked your advice.
Next year I plan to retire.
When we undertook this project, we set aside X number of dollars to complete it. I believe we can do this within our budget even with the new engine and transmission and no I do not have Leno's money either. It seems that there are some new 6.6 duramax available at a very fair price. I spoke to the supplier today and he said that Barth owner in Colorado was installing one in his 79.If anyone knows who this is pleaase contact me.
I would like to ask this question to the Barthmobile community. If you could have a completely rebuilt Barth from the ground up, what would you pay? To buy a used 24 ft SOB with any quality I would estimate 40 to 100 grand. And you still would not have a Barth.
We have a Chinook that we use regularly and it is very nice. But all the while I am using it, I am longing for the Barth.
When I look at this Barth, I can't help the feeling of pride I get from being a Barth owner.
I'll let you know what we decide but we are leaning toward the diesel.
Again thanks very much
Ed

quote:

Originally posted by Lovestogo:
What a great group!!!
Thanks for all your advice.

--------------------- ---------------------

quote:

Originally posted by Lovestogo:
We plan to completely gut the interior, rewire, replumb,foam insulate, build and install all new cabinetry and furniture to accomodate a new layout better suited to our needs and wants. ... to formulate the correct layout.

What kind of layout do you plan on installing? Do you have a doodle? I gutted and redid my interior so I know how quickly the money gets chewed up. That's with me and some friends doing 99% of the work. Go to my signature profile and click on the link "The Story"

quote:

Originally posted by Lovestogo:
I am on the Barthmobile site daily and have learned much from it. I feel as though I know some of you guys personally which is why I asked your advice.

Yup, I can relate.

quote:

Originally posted by Lovestogo:
It seems that there are some new 6.6 duramax available at a very fair price. I spoke to the supplier today and he said that Barth owner in Colorado was installing one in his 79.

Seeing that the Duramax is an engine that needs an ECM, wiring harness, additional engine mounting brackets, transmission and other items, does he sell a kit that will do all of this? If you’re going to do this I think finding a low mileage wreck might still be the way to go...

quote:

Originally posted by Lovestogo:
I would like to ask this question to the Barthmobile community. If you could have a completely rebuilt Barth from the ground up, what would you pay? To buy a used 24 ft SOB with any quality I would estimate 40 to 100 grand. And you still would not have a Barth.

It would be around 40-55 and a coach like...

http://barthmobile.com/eve/forums/a/tpc/f/6041087061/m/7451049802

http://barthmobile.com/eve/forums/a/tpc/f/6041087061/m/3181077512

http://barthmobile.com/eve/forums/a/tpc/f/6041087061/m/6051063091

Now, at this stage of the game I would be breaking the cardinal rule... "If you can only afford an x dollar coach then you really can't afford an x dollar coach"

quote:

Originally posted by Lovestogo:
When I look at this Barth, I can't help the feeling of pride I get from being a Barth owner.

Most of us here can relate to that statement. Would you share some pictures of your pride and joy?

quote:

Originally posted by Lovestogo:
I'll let you know what we decide but we are leaning toward the diesel.

Good luck. If you are going to do this, take plenty of pictures and keep good notes.

Lovestogo wrote:
>I am considering replacing the 454 engine with

Have you given consideration to modifying the 454? I'd love to hear what the circle of wise men have to say on the Banks exhaust system and/or the Edelbrock EFI...
http://store.bankspower.com/Categories.aspx?Category=bc...66-9755-052963490841
http://www.edelbrock.com/automotive_new/mc/efi/pro-flo_chevy_bb.shtml

Or what about putting a stock EFI system in place from a more recent year?

What gives the bang for the buck, and what is the point of diminishing returns?
Happy Thanksgiving!
Matt

Well, if you're set on a diesel, there's always the Peninsular Engines' 6.5L TD; mine is done and should ship tomorrow (depending on the Holiday sked). For $8,975 delivered (+ ~$1,300 installation), I'm getting:

All new (2006 production) AMG short block
Rated at 230 HP (vs. 190 HP stock)
18:1 premium pistons
New injectors, lines, and injector pump.
New non-wastegated turbo (increase blow from 6 psi to 12-13 psi)
New gear drive (replaces timing belt) for camshaft and IP
New oil cooler

I have the stock (rebuilt) 4L80E transmission; apparently it's about 1-1/2" longer than the TH400 hooked to the gaso Barths.

Peninsular mostly does marine conversions for the AMG engines, and get the "pick of the litter" since AMG runs a separate assembly line for Peninsular.

My engine was shoehorned in amongst a 40-unit order for engines for Khazakistan. For airboats!

Whether the 6.5L TD has the same mounting pattern as the 454, I don't know, but for the price it's hard to beat...IIRC, the 454 output is 200HP, but I can't remember torque.

I'm on Barth #3, my second was a 27'er rear bedroom that I loved. It had a 454 with 130K on it and ran fine. All I ever did was reaplce the valve seals.

Keep the 454 add a gear vendors and THIS IS THE MOST IMPORTANT! DUE ALL of Bill H's cooling mods. You'll have years of trouble free performance and parts availble everywhere for cheap...unlike my current diesel.

[QUOTE]Originally posted by BarthBluesmobile:
Lovestogo wrote:
>I am considering replacing the 454 engine with

Have you given consideration to modifying the 454? I'd love to hear what the circle of wise men have to say on the Banks exhaust system and/or the Edelbrock EFI...


We have a Gear Vendors and Banks System on our 34T.. I'll be honest and say other than running a lot smoother the GV didn't make a big difference in overall performance, in fact it made the tranny run hotter and the engine just didn't seem to have the power to use the taller gears. Any time We came to a slight grade, We'd kick it out of OD otherwise the vacuum guage would soon bury itself. I didn't originally go for the Banks instead of the GV because I just couldn't believe the extraordinary claims the Banks people made. Finally, it was time to replace the exhaust system anyway, so we considered the much cheaper Thorleys vs Banks and in the end bought the Banks. I was astonished, the Banks System is all they claimed! I think the old 454 is rated at 220 HP, and Banks claims a 79 HP gain... I believe it! Plus, the engine runs much cooler, now I have the power to really use the GV overdrive and the mileage is finally "Double Digit". Sort of a Barth SS 454, if you know what I mean.

My old 1976 454 is rated at 250 HP @ 4000RPM.
Best torque @ 2800RPM, this is from the chevy man.

Ralph