Reply
 
Thread Tools Search this Thread Display Modes
 
Old 02-04-2018, 10:29 PM   #15
Rivet Master
 
1989 34.5' Airstream 345
Ebro , Fla Panhandle
Join Date: Jul 2013
Posts: 1,168
The original engine in my 345 now has over 180k miles and is pretty healthy. Using little oil, tho some does get past the rear main seal. It may be down a little in power from original, But I've driven nearly 30k miles on it since I've owned the coach, lots of that in mountains of Colo and the PNW. Nearly 7 k of that towing a car. Can easily cruise in the high Sixty mph with the over drive. Have found myself in the mid seventy mph when not paying attention, while in favorable conditions. I usually cruise around 63 for fuel economy. And Generally get 7 or 8 mpg.

That to me is very satisfactory performance from the high mileage 454 gasser.
The engine noise is probably less than the diesels, and the lighter weight is a plus in weight distribution and front end longevity.

It's been interesting hearing from diesel owners thinking of joining the coming motorhome traveling rally, saying that anything over 58 or so is pushing their rigs.
So yes the commercial diesel are probably longer lived that the BBC, but they don't seem much better at powering these coaches, at least as installed by airstream.

So some where down the line when this engine gives up on me, I'll probably replace it with a new gasser that will fit right in with little extra work in getting it fitted, and probably better power and mpg.

Hearing the trials involved in changing over to a diesel in a former gasser also confirms my inclination to stick with a gasser.

Sorry if this is contrary to the focus of this thread, but may be a sensible counterpoint to consider.

I just hope I don't jinks this engine in saying all of this.
I'm hoping to many more miles on this one.

Cheers Richard
__________________

tevake is offline   Reply With Quote
Old 02-04-2018, 11:15 PM   #16
Rivet Master
 
Keyair's Avatar

 
1984 34.5' Airstream 345
Foothill Ranch , California
Join Date: Mar 2010
Posts: 4,570
Images: 1
No problems Richard, and your input is a valid counterpoint.
My MH’s original engine looks like it expired at about 70k miles after at least one documented overheating episode. I know of some that have lasted more than 100k but they are almost exceptions, and yours is amazing!!!!
I think it’s fair to have a balanced discussion of pros and cons and I welcome it. Who knows, my Jasper remanufactured engine may prove to be a gem and the Cummins might never make it under the doghouse!
The GM crate 8.1L/502ci is attractive, and strong, but I am unsure if it’s cam and setup is ideal for a Motorhome. Also last time I looked it was about $8,000, bare.
Maybe an LS would work!

There is one other angle that I have not thrown in yet, but it’s another interesting point... Smog, or Emissions compliance.
You may live in a state or area that does not require it, but many do, and I predict it will be coming for most of us. Here in CA, it’s here now. Even a 16,500lb Motorhome has to pass its emissions test to be registered every 2 years. That means the old Carb has to be within spec and all the emissions gear be visually there and functional. This is a pretty tall order, for us, and the 1980’s technology.
I know someone is gonna tell me to register elsewhere, and point out that CA sucks, etc, but please keep your opinions to yourself, as it’s just a distraction. I believe smog and testing will catch up with us all.
There are options... convert to a later GM TBI or Approved MSD Atomic Injection, at about $1000/1500 min plus the cost of having the system verified by the smog referee, and then you still have to have it smogged every 2 years...
Or, put a Diesel in.
Now, in CA, currently, the Diesel engine has to have come from a road vehicle, newer than the vehicle it’s transplanted into,
and be a proven Fed or CA smog approved engine, and be in its original smog approved configuration.
If the Diesel engine is from a 1998 or earlier vehicle, after the Smog referee has verified it, there is no further smog test required(currently). If the motor is post 1998, after Referee approval you still have to smog every 2 years to the spec of the donor vehicle.

Now, you begin to see why I personally selected a 1990 Cummins from a D250 Pickup. It has the motor plate on it still, that verifies this.

There is also the “value” discussion.
It is already becoming clear that Diesel powered Motorhomes are fetching more money.

Hopefully I will get admin approval soon so I can begin to post the info I have amassed.
__________________

__________________
My name is Steve.... and I am an Alumaholic!
Working in my Garage is like playing TETRIS with Tools!
Keyair is offline   Reply With Quote
Old 02-05-2018, 06:46 AM   #17
2 Rivet Member
 
Schoharie , Unknown
Join Date: Jan 2018
Posts: 68
This is a very interesting thread. I will be curious at the overall cost of the conversion. It doesn't appear to be very cost effective. I have heard that pre-smog diesel engines are going for a premium, plus there is a finite number of them. Most gas engine rebuilders will match your cam to the application for maximum power, so having the wrong cam may be the owners fault when they ordered the rebuild. While a diesel engine may take more abuse, but why would you abuse your equipment? I wish you good luck with this project!!
EZTOO is offline   Reply With Quote
Old 02-05-2018, 11:03 AM   #18
3 Rivet Member
 
OttawaValleyGuy's Avatar
 
1991 35' Airstream 350
Barry's Bay , Ontario
Join Date: Aug 2008
Posts: 152
I have owned several Airstream motorhomes and have yet to replace a 455
Heat and hi rpms are the killers
The 454 has a high torque
If you let the engine do the work properly by letting the revs drop. To about 2200
Before downshifting you may not be the first over the top but you will get a lot of miles out if the 454
A crate drop in is a pittance in cost versus switching to a diesel
The extra weight of a diesel on your front end is also a problem as is the noise and smell
And since when will the body and undercarriage last for a half a million miles
KISS stick with a 454 and enjoy your life
__________________
Howard and Ann Schutt
OttawaValleyGuy is offline   Reply With Quote
Old 02-05-2018, 11:29 AM   #19
Keen amature
 
martin300662's Avatar

 
1975 20' Argosy 20
Chestfield , Kent
Join Date: Mar 2014
Posts: 2,667
I get the impression the thread has deviated somewhat from I think was it's intended scope of documenting which diesel to pick and how to swap if you are doing a conversion.

Justifying the conversion vs dropping in a replacement 454 seems a totally different subject to me.
martin300662 is offline   Reply With Quote
Old 02-05-2018, 12:37 PM   #20
Rivet Master
 
mayco's Avatar

 
1982 31' Airstream 310
champaign , Illinois
Join Date: Oct 2012
Posts: 3,597
Quote:
Originally Posted by martin300662 View Post
I get the impression the thread has deviated somewhat from I think was it's intended scope of documenting which diesel to pick and how to swap if you are doing a conversion.

Justifying the conversion vs dropping in a replacement 454 seems a totally different subject to me.

I agree with Martin here. I don't think that "payback" or justifying the swap in dollars and cents is Steves purpose of the discussion he opened up. If that was the case, none of us would own and "use" one of these antique beasts to start with. Steve has the skills, knowledge, and tools to pull off a diesel swap doing most, if not all, the work himself. So he is in a different situation than most of us here on the Motorhome forums. In his case, the only justification needed is "because he wants to". Which is awesome to me. Looking forward to following the thought process here and I'm sure I'll learn a great deal. If you take a look at the first post, there is no reference to the cost or payback in better fuel economy or reduced maintenance $$$.
mayco is offline   Reply With Quote
Old 02-05-2018, 01:10 PM   #21
Rivet Master
 
Keyair's Avatar

 
1984 34.5' Airstream 345
Foothill Ranch , California
Join Date: Mar 2010
Posts: 4,570
Images: 1
Quote:
Originally Posted by martin300662 View Post
I get the impression the thread has deviated somewhat from I think was it's intended scope of documenting which diesel to pick and how to swap if you are doing a conversion.

Justifying the conversion vs dropping in a replacement 454 seems a totally different subject to me.
Spot on, Martin.

I do believe in people posting their opinions tho, and these will be a footnote to the top 6 posts that I have reserved for my original idea of documenting the actual diesel conversions...
I have written to the Admins, but no response yet.

On the subject of costs for a Diesel swap, I think there are two extremes and lots of space between to fill to suit your budget and skillset!

Option 1:
Buy a Diesel engine of your choice, rebuilt or needing no work, add a transmission that will work, drop that at a specialist in doing swaps and let them handle it. Most likely these places can furnish an engine and trans, and give you options.
My best guess is that the hardware will be $15k and $25k, and the install maybe $10k.

Option 2:
Buy a good used Diesel engine and transmission for $4k to $10k and do the same as option 1. I am seeing a guy on Ebay who does brisk business parting out Diesel school buses, etc, and ships you the whole setup, as a "Frame-Cut" for under $5k.

Option 3:
This is what many have done. Buy a used Diesel diesel or rebuilt, like Option #1, or 2, add transmission, and put it in yourself. My guess would be you will be between $7k and $12k.

Option 4:
This is me.... and my cross to bear...
Buy a used engine(Cummins 12v for $600), strip, assess, and rebuild it, doing upgrades to engine, injection, exhaust, turbo, intake, Intercooler, and suit your power needs(+ $3000 ish).
Find a used transmission(Prob Allison 5 or 6 speed for $1500) rebuild myself($500/$1000).
Add fueling, cooling and controls as needed, and install myself.
My best guess is that I will be in the $7/8k range for a totally built out Cummins Diesel setup, with 350hp and 800ftlb of torque that will do between 12mpg and 16mpg in similar usage, which is double the 454, double the torque, and outlast me.
For the record, I have a receipts for the Engine replacement in my MH from 2008, and Trans rebuild in 2006, and they total almost $15000.

The reason for this thread is to document how people have done it, what they used, the problems and solutions.
We all then have a reference point, so we can understand the choices, costs, and make decisions.
__________________
My name is Steve.... and I am an Alumaholic!
Working in my Garage is like playing TETRIS with Tools!
Keyair is offline   Reply With Quote
Old 02-05-2018, 02:02 PM   #22
Rivet Master
 
Keyair's Avatar

 
1984 34.5' Airstream 345
Foothill Ranch , California
Join Date: Mar 2010
Posts: 4,570
Images: 1
Thanks Mayco!

Really, I'm just a "Johnny come lately" to this... and freely admit that my swap is in the distance...

However, I am a research monster, and believe I have gathered a lot of info, mainly on Cummins fitment.

I believe that will be a big part of this thread simply because its been done, its documented, and makes lots of sense...

Choctawmel has proved to be an absolute BEAST with his swap... I'm am still amazed at his drive and energy despite all odds! Kudos!!!!
I am sure he will have lots of do's and don'ts to add!

GWBaker before him, who appears to be long gone from this community.... did something really special, and there is much to be gleaned from his thread. I wonder where his motorhome is these days!
Also, I believe someone has a converted Funeral Coach with a Cummins in... Smartstream or Spicestream???

Dave(Wxbouy), posted pics of his OEM Cummins 345 a few years back and now I actually know what I am looking at/for the info will be invaluable.

I wish I had known, posted what I now know, like the Cummins needing a specific exhaust manifold that tucks the turbo in tight to the engine, in either top, or under slung configuration. The stock "Pickup" exhaust pushs the Turbo outbourd to far and hits the floor frame of the MH, as Choctawmel will attest!

Cole3444's Cummins converted 310 is amazing too..... whoever did the conversion, knew what they were doing and it looks a carbon copy of the OEM Cummins.

In addition, the two known Duramax conversions will add options too, and I hope to get info from at least one of the owners, that I can add to documentation.
__________________
My name is Steve.... and I am an Alumaholic!
Working in my Garage is like playing TETRIS with Tools!
Keyair is offline   Reply With Quote
Old 02-05-2018, 02:09 PM   #23
Dazed and Confused
 
Isuzusweet's Avatar

 
Currently Looking...
1983 31' Airstream310
Hillsburgh , Ontario
Join Date: Sep 2012
Posts: 3,527
I would just like to add a caveat to what info I have posted before.
FYI before plonking down some dough-ray-me on a nice Isuzu 6 cylinder or even a Cummins, make sure you know what application it came out of. An excavator Isuzu 6bd1T is different to one out of a truck. The excavator engine is designed to run at one rpm only; it is not designed for variable rpms.
Some applications of the Cummins 6bt's are the same way.
Be very carefully when choosing your diesel.
I'm sure someone can explain the differences far better than I can.
Cheers
Sidekick Tony
__________________
Per Mare, Per Terram and may all your campaigns be successful.

“It’s a recession when your neighbor loses his job; it’s a depression when you lose your own.” "Harry S Truman"
Isuzusweet is offline   Reply With Quote
Old 02-05-2018, 04:27 PM   #24
Rivet Master
 
Smartstream's Avatar

 
1982 28' Airstream 280
Port Angeles , Washington
Join Date: Aug 2008
Posts: 1,702
I guess I should put my 2 cents worth. The last gas to diesel conversion I did was about 10 years ago. I put an "A" series Cummins 6 cylinder turbo in my 1938 Ford COE truck. The biggest issue is making it fit. Next is mating to transmission unless of course you are using an engine/transmission package. The small stuff like clutch and throttle linkage, radiator, wiring and a return fuel line, can be challenging. The biggie is will it fit.

Tony I don't believe there is much difference between a highway and an industrial engine, maybe a little tuning in the fuel pump but not much in the engine internals.

The "B" series Cummins is an inviting swap because in addition to being a great engine, they are cheap and plentiful. We know the Isuzu fits but I don't know if you picked one up from a cab forward truck today it would have the same turbo/exhaust fitting as the units that Airstream used. I might even look at a 4 cylinder because you might find one that puts out power comparable to the 454. I know that many here have "Tim Taylor" syndrome needing more power. I would caution here something learned playing with older cars and trucks, you can make it go faster but you still have to make it stop. I don't see many here bragging about the brakes on their P-30.

One last thing, such a swap can be fun and challenging if you are in to that kind of thing. And very rewarding if you are successful.
__________________
Cheers, Dan
________________________________________


"Socialist governments traditionally do make a financial mess. They always run out of other people's money. It's quite a characteristic of them."
~ Margaret Thatcher ~
Smartstream is offline   Reply With Quote
Old 02-05-2018, 04:58 PM   #25
Rivet Master
 
bobmiller1's Avatar

 
2005 34' Classic S/O
2006 39' Land Yacht 396 XL
north blenheim , New York
Join Date: Sep 2012
Posts: 1,931
OK, time to add my position....I am acquiring the parts for my conversion for next winter. Other than the granite countertops/farm sink/ electrically operated dinette table, the only other item is the Detroit/Allison conversion which will be during the third year, body/clearcoat will be the fourth year, God willing, Regards, Bob
bobmiller1 is offline   Reply With Quote
Old 02-05-2018, 05:11 PM   #26
Rivet Master
 
Waipio Rim's Avatar

 
1984 31' Airstream310
Honokaa , Hawaii
Join Date: Jun 2010
Posts: 856
One more sidebar - a conversion like this with all the bugs worked out will add a bunch of value to the coach. It could be a good investment.
Waipio Rim is offline   Reply With Quote
Old 02-05-2018, 06:40 PM   #27
Keen amature
 
martin300662's Avatar

 
1975 20' Argosy 20
Chestfield , Kent
Join Date: Mar 2014
Posts: 2,667
I have to ask....has anyone considered buying a 7.5ton, mid 2000's NQR and swapping the drive train?
martin300662 is offline   Reply With Quote
Old 02-05-2018, 07:02 PM   #28
Rivet Master
 
Keyair's Avatar

 
1984 34.5' Airstream 345
Foothill Ranch , California
Join Date: Mar 2010
Posts: 4,570
Images: 1
I’ll let you take the lead on that one Martin... Add sound of Keyair’s chainmail gauntlet hitting the ground.....
__________________

__________________
My name is Steve.... and I am an Alumaholic!
Working in my Garage is like playing TETRIS with Tools!
Keyair is offline   Reply With Quote
Reply


Currently Active Users Viewing This Thread: 1 (0 members and 1 guests)
 
Thread Tools Search this Thread
Search this Thread:

Advanced Search
Display Modes

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are Off
Pingbacks are Off
Refbacks are Off


Similar Threads
Thread Thread Starter Forum Replies Last Post
HELP! Accidentally putting E-85 instead of diesel in AI roadmama Sprinter and B-van Forum 66 11-29-2015 05:31 AM
Another reason to keep your Airstream Diesel Motorhome frankandsue Airstream Motorhome Forums 5 09-23-2010 06:21 AM
Putting AS on Blocks/ Electric brake conversion ? airhead Axles 4 06-27-2004 03:52 PM
Putting my trailer undercover Stefrobrts Our Community 32 02-05-2004 08:57 AM
Putting in new carpet wardster All Argosy Trailers 1 02-03-2004 12:02 PM


Featured Campgrounds

Reviews provided by

Disclaimer:

This website is not affiliated with or endorsed by the Airstream, Inc. or any of its affiliates. Airstream is a registered trademark of Airstream Inc. All rights reserved. Airstream trademark used under license to Social Knowledge LLC.




Copyright 2002- Social Knowledge, LLC All Rights Reserved.

All times are GMT -6. The time now is 02:23 PM.


Powered by vBulletin® Version 3.8.8 Beta 1
Copyright ©2000 - 2019, Jelsoft Enterprises Ltd.