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#846 Cummins Swap.
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andy1canada
Posted 2018-11-12 3:12 PM (#6035)
Subject: #846 Cummins Swap.


Extreme Veteran

100100100252525
Location: Victoria, BC. Canada
Howdy,

Got an album started - sort of - on my Cummins swap. The picture uploader is giving me serious grief and I need to sort that out before I get any inclination to try to put more pics/video up. Will keep you posted on my progress figuring out what I did wrong, or, what's wrong with the upload system if possible.

Pulled the bumper a couple of days ago and man is that sucker heavy. Will be looking to shave off another 50 lbs or so off of it while still being able to safely tow up to 5000 lbs. I've still got another 240 lbs or so to lose off the ass-end of this coach in order to maintain some semblance of the OEM rear-wheel GVW.

http://www.fmcowners.com/mbbs22/photos/photo-thumbnails.asp?albumid...

Siphoned out most of the gas out of the 'full' tank today and while doing so I reminded myself how brilliant of an idea it was to top-up the tank before I left Seattle.

Looking forward to getting going on this...

Terry
#846
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byegorge
Posted 2018-11-12 11:22 PM (#6036 - in reply to #6035)
Subject: Re: #846 Cummins Swap.


Veteran

10025
Location: Olympia, Washington
Siphoning it out beats running out any day.
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dkarnath
Posted 2018-11-13 11:46 AM (#6037 - in reply to #6036)
Subject: Re: #846 Cummins Swap.



Extreme Veteran

100100100100252525
Location: Medford, OR
Cool!
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hemi354az
Posted 2018-11-13 8:52 PM (#6039 - in reply to #6036)
Subject: Re: #846 Cummins Swap.


Extreme Veteran

100100100252525
Location: Scottsdale, Aridzona
I would have used the drain plug in the bottom of the gas tank. Never did like the taste of gasoline.
Drip ON ! Lou #120
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byegorge
Posted 2018-11-15 7:48 AM (#6042 - in reply to #6035)
Subject: Re: #846 Cummins Swap.


Veteran

10025
Location: Olympia, Washington
Nothing beats a long afternoon of gasoline burps. I'm with you on the taste Lou but what about ethel and aviation fuel surely they must taste better.
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hemi354az
Posted 2018-11-15 9:15 AM (#6043 - in reply to #6042)
Subject: Re: #846 Cummins Swap.


Extreme Veteran

100100100252525
Location: Scottsdale, Aridzona
The 115/145 AvGas plus Manganese plus Jack Daniels that we used in the Unlimited Race Planes and HydroPlane Boats is not too bad . . . but the JP-4 and now JP-8 makes a lousy Manhattan.
Chug-A-Lug ON ! Lou #120
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dkarnath
Posted 2018-11-15 9:47 AM (#6044 - in reply to #6043)
Subject: Re: #846 Cummins Swap.



Extreme Veteran

100100100100252525
Location: Medford, OR
This reminds me of my late Grandpa, he once told me, "I feel really good (he was in his mid/to late 70's) for having my hands in gasoline my entire life"....He was a great mechanic.
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LCAC_Man
Posted 2018-11-15 10:14 AM (#6045 - in reply to #6044)
Subject: Re: #846 Cummins Swap.


Elite Veteran

50010025
Location: Oceanside, CA
You going to use sheets of plywood to build a work surface for moving the engine in and out? 4 or 5 of the cheapy moving blankets from Harbor Freight ($5-$6 each) come in handy as well, you'll get tired of that hard cold surface..
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dkarnath
Posted 2018-11-15 12:08 PM (#6046 - in reply to #6045)
Subject: Re: #846 Cummins Swap.



Extreme Veteran

100100100100252525
Location: Medford, OR
I use the Harbor Freight moving blankets all the time when laying or kneeling on the ground, they are great. The small black one they have is my favorite, I also have a larger blue one, buts it's kind of cumbersome to move around, but it would be good for this type of job because Terry's going to be snuggling and loving on the blanket under there for a while.....
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andy1canada
Posted 2018-11-15 8:03 PM (#6047 - in reply to #6035)
Subject: Re: #846 Cummins Swap.


Extreme Veteran

100100100252525
Location: Victoria, BC. Canada
Hey,

Yeah Lou, was already feeling like a dick-head for 'topping up' the tank right before an engine swap and after I siphoned most of the gas out - didn't swallow a drip, sorry - I decided to crawl under the coach for a look at the bottom of the tank only to discover the drain plug; however, I do believe I took the better route to siphon the bulk of it out vs trying to figure out how to get several jugs under that sucker without losing a bunch of it. Good to know there's a drain there regardless as I will have to flush and clean the tank at some point before diesel goes in there.

Dan, buddy, sounds like you, too, were close to your Grandpa as I was, too, my own. We lost him in 82' to colon cancer; battled it for 2 yrs. Much of what I know about mechanical stuff - which, frankly, ain't much - I owe to him; like the time he and I did an engine overhaul on Granny's 1960 Envoy (like a Vauxhall) right in his carport. Seldom a day goes by that I don't think of him.

Yes on the plywood and no on the blankets; coverall's will suffice, thanks. Pussies!

Went out after work and measured up the bumper assembly - a very substantial assembly at that - then did a sq/ft weight calculation on the weight based on known sq/ft weights of 1/4" plate steel, 3/4" plate steel and the 5 or 6/32" stainless bumper itself, which I estimated at about 9 sq/ft. Wish I had a scale.

My rough calculation its total weight comes out at approx 135 lbs. Little wonder it nearly killed me carrying this sucker a few feet away from the coach.
I invite any and all rebuttals on this estimate as I really would like to nail this down for future reference.

Just go out and rip the bumper off the back of your coach and weigh it - take one for the team!

This said, it strikes me as an invitation to explore losing at least 50 lbs or more off this structure while still retaining a 5000 lb towing standard.

50-lbs or more off the aft-most-ass-end of this baby might not seem worthwhile, but would be pounds well lost I figure.

Back at it this weekend.

Cheers,
Terry
#846

Edited by andy1canada 2018-11-15 8:05 PM
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LCAC_Man
Posted 2018-11-16 7:59 AM (#6048 - in reply to #6035)
Subject: Re: #846 Cummins Swap.


Elite Veteran

50010025
Location: Oceanside, CA
Unless you are willing to build the structure in aluminum I don't think you'll be able to extract 50lbs...you might shave 25lbs by using 3" square tube (1/8" wall), you will have a fair amount of time in it to reproduce the shape and mounting/locating positions to match both the frame rails and bumper..
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andy1canada
Posted 2018-11-18 7:58 PM (#6059 - in reply to #6035)
Subject: Re: #846 Cummins Swap.


Extreme Veteran

100100100252525
Location: Victoria, BC. Canada
Weighing in:

https://www.ebay.com/itm/Klau-Mini-Weighing-Mini-Crane-Scale-OCS-L/4...

Small investment I figure to put the pounds where my 'mouth' is.

Terry
#846
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LCAC_Man
Posted 2018-11-19 7:11 AM (#6060 - in reply to #6059)
Subject: Re: #846 Cummins Swap.


Elite Veteran

50010025
Location: Oceanside, CA
You mentioned looking for a simpler solution for rear air bags, you could replace the rear shocks with a heavy duty coil over shock or a bellows air lift shock like these https://www.airliftperformance.com/product/82607/ You would have to do some rework to the upper shock mount tower (but it needs it anyway, both of mine were cracked from poor installation welding). This would be a much lower fabrication investment (labor dollars) but a bit more on material cost.
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andy1canada
Posted 2018-11-19 8:59 AM (#6061 - in reply to #6035)
Subject: Re: #846 Cummins Swap.


Extreme Veteran

100100100252525
Location: Victoria, BC. Canada
Morning,
Am I correct in assuming that the shocks load-rating basically splits/shares the vehicles rear axle weight, ie 10,500 lbs., or, over 5000 lbs each?

If that's the case then these puppies would be sorely underrated at a max load rating of 1700/lbs or so. No?

Before I make any decisions about any rear or front suspension upgrades I need to do two things:

1) - finalize any weight reductions I can make back there to compensate for the heavier engine. My little crane-scale will surely come in handy here in arriving at a real net butt-weight when I'm done. Frankly, in the end I plan to be very close to OEM rear axle weight when I'm done.

2) - actually learn something about suspension geometry & engineering. I know dick, really. Lots of questions and stuff to learn here. For example, why did you (Len) decide not to use the simpler Timbren rubber springs vs the set up you used and what benefits have you realized in the end? (pun intended) Are the rubber spring set ups many have used meant moreso to alleviate trailing-arm lateral movement which causes 'tail-wagging' driving issues, vs any useful rear weight transfer or increased support function?

One thing I do know now is that the handling & driveability of #846 has to end up as good, or, better than it is now. I'd rate #846 a strong 6 or maybe 7 out of ten (10 being sportscar like handling) as it drives now. Not quite at the hand over the keys to one of my kids to 'take'r for a spin' stage yet but I will try to get there.

Thanks and have a great day!
Terry
#846

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LCAC_Man
Posted 2018-11-19 9:56 AM (#6062 - in reply to #6061)
Subject: Re: #846 Cummins Swap.


Elite Veteran

50010025
Location: Oceanside, CA
"Am I correct in assuming that the shocks load-rating basically splits/shares the vehicles rear axle weight, ie 10,500 lbs., or, over 5000 lbs each?"
No...unless you plan on removing the entire torsion suspension and relying only on the shocks.
All/any of these (air bag, air shock, timbren, sumo spring, coilover shock, etc...) solutions would be "suspension assist"...my current air bags are the heavy duty style and are only rated at 2500lbs each...the existing/factory shocks don't provide any "suspension" at all...they provide dampening.

Edited by LCAC_Man 2018-11-19 10:16 AM
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LCAC_Man
Posted 2018-11-19 10:24 AM (#6063 - in reply to #6035)
Subject: Re: #846 Cummins Swap.


Elite Veteran

50010025
Location: Oceanside, CA
While I know a lot of you guys love to talk about the benefits of "Timbrens"...I already had them on my coach when I bought it...maybe they made some improvement over stock...but it was still like driving a wet sponge. The truth is they are glorified long travel bumpstops that really just hide the fact that your rear suspension is worn/too soft to do the job. Sumo Springs are another version of Timbrens...again...if you need just a little bit of extra sway control they probably would do the trick...if you need to (substantially) restore/increase suspension capacity they are not up to the job.
Why did I do the long trailing arm air bag install...? To provide additional suspension support farther back on the frame rails where it is badly needed with the extra weight and to accomodate the type of towing I do.

Edited by LCAC_Man 2018-11-19 10:28 AM
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ricogomez
Posted 2018-11-19 11:07 AM (#6064 - in reply to #6035)
Subject: RE: #846 Cummins Swap.


Veteran

100
Location: Houston, Texas
Our main purpose or need for installing the rear airbags, will be to raise the rear a
few inches without lifting the front end as well while trying to adjust the rear suspension
up, right now if I adjust it, the front goes up at the same time just as much as the rear.

Ours has always been great going down the road before and after our diesel conversion,
now we will have to install a GPS Cruise Control to keep it from blowing & peeling the
stripes off.



Rico & Carmen
397
12 V Cummins & 6 Speed Ally.
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BigRabbitMan
Posted 2018-11-21 2:09 PM (#6065 - in reply to #6035)
Subject: Re: #846 Cummins Swap.



Elite Veteran

100025
Location: Cottage Grove, OR
Here is a description of the air bag setup for coach 809. Moving the support point rearward effectively shifts weight from the rear wheels to the front wheels as the pivot point for the coach body is shifted rearward. The coach pivot point remains the same. This aligns with the effect that Frank B. observed when he put airbags on his coach. The front of the coach lowered down.

"Also, another major difference in 809 is it has an airbag rear suspension, which I engineered. I have my rear torsion bar adjusters backed out all the way, no timbrens, just a 1 1/2" suspension bumper which the suspension arm sets right down on when there is no air in the suspension. My air bags are mounted 12" behind the wheel centerline. I run 40 lbs of air in the bags and the coach sits at the recommended height in the manual. The rear rides on air bags and not torsion bars...so the coach chassis is being held up behind the rear wheel centerline. My rear shocks are mounted just in front of the bags still behind the axle, which gives them more travel than the stock location, which was a bad design in my opinion." - Steve Centracchio.
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ricogomez
Posted 2018-11-21 2:37 PM (#6066 - in reply to #6035)
Subject: RE: #846 Cummins Swap.


Veteran

100
Location: Houston, Texas
Hey Mr Stephan, was wondering if you knew Steve and if he had a Diesel engine
and what type of Air Bags he used ????


Thank you




Rico & Carmen

397



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BigRabbitMan
Posted 2018-11-21 4:58 PM (#6067 - in reply to #6066)
Subject: RE: #846 Cummins Swap.



Elite Veteran

100025
Location: Cottage Grove, OR
ricogomez - 2018-11-21 12:37 PM Hey Mr Stephan, was wondering if you knew Steve and if he had a Diesel engine and what type of Air Bags he used ???? Thank you Rico & Carmen 397

He has a Cummins engine in his coach. I will email his contact information so that you can reach him with your questions. He is in Tucson, AZ.
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andy1canada
Posted 2018-11-21 6:55 PM (#6069 - in reply to #6035)
Subject: Re: #846 Cummins Swap.


Extreme Veteran

100100100252525
Location: Victoria, BC. Canada
Would be good to see pics of his install and find out what air bag kits he used.

Terry
#846
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LCAC_Man
Posted 2018-11-21 6:58 PM (#6070 - in reply to #6035)
Subject: Re: #846 Cummins Swap.


Elite Veteran

50010025
Location: Oceanside, CA
"Moving the support point rearward effectively shifts weight from the rear wheels to the front wheels as the pivot point for the coach body is shifted rearward."

Pretty standard geometry/physics; basically the farther back you can carry/spread the load the better... Long levers work good...short levers will work you good..
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BigRabbitMan
Posted 2018-11-21 7:04 PM (#6071 - in reply to #6069)
Subject: Re: #846 Cummins Swap.



Elite Veteran

100025
Location: Cottage Grove, OR
andy1canada - 2018-11-21 4:55 PM Would be good to see pics of his install and find out what air bag kits he used. Terry #846

I will send his contact info to you.
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andy1canada
Posted 2018-11-21 7:06 PM (#6072 - in reply to #6035)
Subject: Re: #846 Cummins Swap.


Extreme Veteran

100100100252525
Location: Victoria, BC. Canada
Thanks Stephen but I have it already. I'll give him a ding.

Terry
#846
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andy1canada
Posted 2018-11-23 2:12 PM (#6073 - in reply to #6035)
Subject: Re: #846 Cummins Swap.


Extreme Veteran

100100100252525
Location: Victoria, BC. Canada
Too busy lately but found a little time this morning to finally get the rear upper and lower rad grill sections off. I sure hope these two pieces are the only ones I need to take off to get this engine swap done. I'm going to try to simplify how these things go back on. Maybe join the upper and lower sections into one piece that easily slips into two slots/pockets at the bottom with only two simple screws/bolts at the top. Have to think about it...

Couple more pics in the album.

Terry
#846
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