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Veteran
 
Location: Oslo Norway | Congratulations to you Stephen, Eric and the rest of the Duramax-crew.
Great work!
Kjetil |
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Veteran
Location: Olympia, Washington | Len, Stephen:
I have read about 'shear plating' to stiffen the structure to better handle the weight of a Detroit diesel, is that a concern with the Duramax swap? Thanks. |
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Elite Veteran
Location: Oceanside, CA | The 8.2 is over 200lbs heavier than the Duramax, I'm also replacing the Onan 6.5kw with a Yanmar than is 115lbs lighter, and moving the battery forward. I don't think weight will drive structure changes.
Additional torque/power is another matter, while I'm still not sure it will be required, I'm going to make my new engine and transmission crossmembers more structurally significant portions of the frame, the original engine crossmember that incorporated the circular design to accommodate the exhaust couldn't have provided much if any additional frame rigidity. |
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Elite Veteran
Location: Victoria, BC. Canada | Great observations Lenny! Can't wait to see what the outcome actually is. If we don't strive to make improvements - in spite of the prospect of failure - nothing will get better.
Please do keep us posted on your progress. It's people like you and Stephen and others who strive for improvement in what was originally a very good idea - that keep us all glued to our screens.
Terry
#846 |
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Expert
Location: Cottage Grove, OR | As I recall from memory (which is dangerous in my case!) the Detroit 8.2 weighs about 1400 pounds and the Cummins 5.9 about 1000-1100 pounds and the Duramax about 850 pounds and the 440 about 650-700 pounds. One problem with all of these numbers is getting them with the engine at the same state of "dress". The best comparison would be with them all fully dressed as they would be when installed in a vehicle with manifolds, generators, carbs, oil filter, etc. all installed. I haven't found those numbers as of yet. At this point, I leave that up to others. It would be good for the community if those numbers were found for those engines and any other engine under consideration with links to the source of the data so correct interpretations could be verified. Upgrading the transmission to an Allison also adds about 200 pounds to the mix.
But pound numbers are only part of the mix to be considered. Leverage is the other factor. A pound added to the transmission has half the leverage effect of a pound added out at the end of the frame. Due to the length of the Allison 1000 transmission, my engine is a couple of inches further back than the stock position of the 440. But the center of gravity of a V8 is further forward than the center of gravity of an inline six. I replaced the heavy brass radiator that was out at the end of the frame with a light early 2000's aluminum radiator. The 440 has a torque rating of about 350 ft.lbs. while the Duramax is rated at about 650 fl.lbs.. That is a factor to be considered, but it is a variable factor as torque is only generated as called upon by the fuel pedal. Weight is there 100% of the time including when parked!
In my and Len's case with the double overdrive transmission, we are able to retain the stock high ratio gearing between the drive shaft and the ground. That reduces the torque needed from the drive shaft/engine to achieve a given forward force as compared to diesel setups that have larger wheels and/or lower ratio differentials. All of this and more comes into play when making changes.
As to shear plating, I think that it adds to the stiffness of the body of the coach but if one looks at the structure of the frame members of the coach and how the body is attached to the frame in the rear and where the engine is attached, there is no direct support of the frame members that support the engine as a result of shear plating. So does shear plating solve a flexing issue or does it simply mask it? How much flexing of the engine support members is acceptable? As Len has noted, with and without the 440 causes things to flex. Some expected flex is designed into machines such as our coaches. How much is tolerable is the question! When I reattached the lower portion of the ladder to my coach, all of the bolt holes lined up. To me, that was a good sign that the frame members that support the bumper were in approximately the same position as they were originally. But, yes, that was a static measurement.
Bottom line for me is that shear plating is a good thing as it stiffens the side panels of the coach, but it is not to be expected to materially support a diesel engine nor the torque it generates.
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Elite Veteran
Location: Victoria, BC. Canada | Very interesting Stephen.
Perhaps we might start a new thread focused on chassis capacity based on other owners real-world experiences and results with engine conversions?
Over the 8 or so years I've been involved with FMC's I have read occasional threads about issues with handling and measurable - if not visible - sagging in the butt-end of these things as a result. I think a new thread might be a good idea.
Frankly, I find it hard to swallow that FMC's motorhome was not overbuilt like most other stuff they made. One would imagine that those two primary aft frame members that carry the engine/trans load were stressed/engineered to handle at least twice the projected service weight. FMC tended to build stuff that way. Yet, we all know there were a few recalls on the coaches that, from what I can gather, were addressed.
So, anyone else think this would be a good thread to start? If so, I'd like to see info/results/observations on other projects of today & yesterday. If there were issues, how were they detected or measured? What are the original chassis specs that one can reference to see if theirs has moved any over the years or as a result of an engine swap? Tools and methodology: is a simple laser the way to go? what points beneath the coach can one easily reference? what signs on the exterior to look for? etc etc...
I remember one thread (IIRC) where a guy used a string pulled from one end of the coach to the other to determine if there was any frame/chassis deflection.
Wow! Way too much coffee this morning.
Feedback?
Terry
#846 |
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Veteran
Location: Canton, (Sixes) GA | Mighty 890, 8.2/545, alum radiator weighs in at 16560 with fuel, propane & water tanks full, family (4) aboard, fully provisioned. Sheer plated. One or two finger steering when underway. Very slight bulge aft of passenger side door that has not changed in past 8.5 plus years. Would be good to get coach weighs with qualifying details. I am going to try to get it weighed with just fuel, propane water tanks full, no people or provisions. Scales at Red Oak II 2016? |
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Expert
Location: Cottage Grove, OR |
denshew - 2011-01-05 7:08 AM Stephen – WOW. You have done your homework so should be a great project. My mind is flooded with a hundred questions and suggestions but will just say good luck and wish I was there to lend a hand. Eat the elephant. Denny Well Denny, we ate the elephant!! |
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Expert
Location: Cottage Grove, OR | Here is weight information for 1046 prior to the conversion. At some point, I will weight the coach again and we will see what changed. I also did some ground to end of frame rail measurements immediately before and after removing the 440 and immediately before and after installing the Duramax. The information is below.
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FMC 1046 weights as of 4-8-2011 prior to Duramax conversion.
Current set up is Chrysler 440 with an Allison 545 transmission and Edelbrock MPI fuel injection. Stock radiator converted to 6 rows. A 120 pound internet antenna is centered on the roof near the front. The generator is an Onan Marquis 7000 (290lbs.)
At the time of weighing, the fresh water tanks were full (they are to the right of the centerline near front axel) and the waste tanks empty (they are to the left of the centerline in front of the rear wheel).
Also, to weigh the left side the coach was driven half on and half off the scales. There was a small difference in height so the coach was slightly tipped to the right which would cause a slight weight bias to the right that would not be there if everything was level. The right side weight was derived by subtracting the left side weights from the axel weights. It was a segmented scale so the axel and total weights are all actual scale weight and not calculated.
Cat scale, Dixon, CA
Left right
Front: 5,200 2,480 2720
Rear: 9,500 4,480 5,020
Total: 14,700 6,960 7,740
Frame rail height from ground before and after engine (440 w/Allison) removal:
Left Right
Before: 21” 20 ¼”
After: 21 3/8” 20 ¾”
Rise: 3/8” ½”
Frame rail height from ground before and after Duramax (w/Allison) installation.
Before 27 15/16 27 3/16
After 27 ¾ 27 1/8
Drop: 3/16 1/16 Note: Generator not yet reinstalled.
Note that the difference in rail height by approximately 6 inches was due to measuring to the bottom vs the top of the rail. Also overall coach height changed due to re-jacking/leveling the coach in the intervening time period.
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Hopefully this information will give others something to compare to. At such time as I am able to re-weigh the coach, the numbers will be posted.
Enjoy,
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Extreme Veteran
Location: Scottsdale, Aridzona | Please see Page 7 of "Discussions", Subject - FMC Chassis, messages #862, #863, and #872 by Duramaxer (Kjetil #477 Bergflødt).
All FMCers should review ALL of Duramaxers PHOTOS as he has rebuilt FMC #477 into the GOLD STANDARD that we all aspire.
There are many other PHOTOS of FMCs "without the skin" by others that are also worthwhile reviewing.
Bend(?) ON ! Lou #120
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Veteran
Location: Oslo Norway | Sag on Kjetil, #477 |
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Elite Veteran
Location: Oceanside, CA | denshew - 2015-10-31 11:52 AM
Very slight bulge aft of passenger side door that has not changed in past 8.5 plus years.
Do any of them not have it? I've seen 5 in person, every one of them had that buldge (including mine with no engine in it). |
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Veteran
Location: Olympia, Washington | Is anything being done to increase the 'GVWR' beyond the stock 15,000 Lb. (10K rear & 5K front)? Maybe a better question would be how many 'Coaches' are currently being operated in an overloaded condition (ie: GVW in excess of 15,000 Lbs.)? I have yet to weigh #506 but I have no problem believing it will be in excess of 15,000 Lbs. fully loaded. How does one go about increasing the 'GVWR' of the Coach? What would need to be upgraded the tires, wheels, springs, bearings and/or frame structure? In a bone stock FMC what is the weakest link in the 'GVWR' equation? |
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Contributor
Location: Bluevale, Ontario | Number 645 has a 5.9 Cummins and an Allison 2200, has been shear plated. Have scaled about 5 different times, full of fuel and fresh water and passengers. 15,000 lbs., 10,000 on the rear and 5,000 up front. Have never done individual wheel weights, would be interesting. Maybe at Red Oak. Frank. |
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Elite Veteran
Location: Oceanside, CA | Re-classifying a vehicles GVWR/GCWR is very difficult/impossible depending on what state you're trying to do it in.
From a practical standpoint, you really need to consider what elements drove the current GVWR. After looking at the existing suspension, brakes , chassis structure, tires, and drivetrain the weakest link in that chain is the transmission/driveshaft/parking brake system. I don't know of any applications where the 727 is rated beyond 15000lbs GVWR and I'm not sure how the FMC engineers got comfortable with using a slip driveshaft with only 1.375" 10spline shaft.
The parking/emergency brake must have been the minimum to meet DOT requirements at the time as it the same size as what was installed on my 4000lbs 75 Toyota Landcruiser FJ40 (previous vehicle).
The 140 series Rockwell differential is well below its max rating (I saw references to it being used in 24000lbs GVWR vehicles).
The tires are critical elements, but, most commercial tires in the 19.5" size fit the high weight ratings.
The suspension, while a little soft for higher weights can easily be stiffened with air bags.
The chassis construction is as good as/better than more modern coaches with high GVWR's, the 6" rectangle tube configuration in the drivetrain area is extremely strong.
I haven't spent any time really evaluating the drum brakes/brake surface area capacity, so, it is still something to consider. The duramax/allison is much more effective with engine/trans braking so a considerable amount of the load can be offset with them.
Edited by LCAC_Man 2015-11-01 8:02 AM
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Expert
Location: Cottage Grove, OR | I have copied and pasted all of the above posts from George's post #1311 on from this thread to Duramaxer's FMC Chassis thread as that is where this discussion should be continued.
http://fmcowners.com/mbbs22/forums/thread-view.asp?tid=200&posts=5#... |
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Elite Veteran
Location: Oceanside, CA | Stephen,
Were you able to use the FMC Cruise Control Switch? Looks like it's wired slightly different and may confuse the ECM. Were you successful in making that system work?
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Elite Veteran
Location: Oceanside, CA | A little more research makes it look like if I want to use the factory CC switch I can either disable the "resume/accel" function and use as is or add a couple relays to get all the functionality to work.. |
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Expert
Location: Cottage Grove, OR | We could not use it in its original configuration so we split the actions between two switches. The "on" and "engage" functions remained on the stock stalk. We added a double action momentary switch on the dash to increase and decrease speed. |
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Elite Veteran
Location: Oceanside, CA | That matches what I've been reading...there appears to have been a shift at GM in the early 80's from "Closed" circuit switches to "Open" circuit switches in later electronic cruise control equipped vehicles. I'm leaning toward the relay solution, here's the schematic:
http://www.fmcowners.com/mbbs22/photos/show-album.asp?albumid=127&p...
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Elite Veteran
Location: Oceanside, CA | Stephen,
Did you incorporate the donors headlight switch? Looks as though it could be done without it but a couple relays would be required to produce "switched grounds" rather than power to the Instrument Panel Cluster. Trying to decide if it would be easier to stay with the factory switches or convert now.
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Elite Veteran
Location: Oceanside, CA | Also curious if you attempted to integrate the ambient light sensor? |
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Expert
Location: Cottage Grove, OR | We did not incorporate the donor light switch for the head/parking lights as I like the stock switches. We did change the wiring so that the switches do not carry the load current. They now operate relays that carry the lighting load to the lights themselves. The donor light switch was retained to operate the dash cluster lighting. The donor switch is now behind the bottom of the steering column. The ambient light sensor was not incorporated, but we have the ability to incorporate it at a future date. Someday(!) I hope to do a complete dash reconstruction to properly incorporate the lighting functions and the steering wheel switches for the DIC (driver information center) and possibly the donor's radio as well. I also need a better position for my Manual Shifting momentary switch and the Tow/haul momentary switch. |
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Contributor
| I purchased #09 a few years age. Drove it for awhile then parked it. I'm considering installing a ford 7.3 diesel. Does anyone have any experience with this conversion. I have this engine in my pickup. In my opinion it is one of the best. Appreciate any input. Thanks |
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Elite Veteran
Location: Oceanside, CA | Stephen,
Thanks for the light switch info, I'm still kicking it around and may do similar to what you did.
jadat1,
The 7.3 Power-Strokes are great motors. They are really large and heavy though, with the available transmissions(and resulting total length) they would be a very tough swap. |
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The Dieselfication of Coach 1046
