The time has come!

As a number of you know, I have long felt that if an FMC is to be converted to a diesel engine today, the best engine to use is the GM Duramax 6.6L turbo diesel along with the Allison 6spd double overdrive transmission.  Some indepth discussion of what engine to use has been discussed in other threads.  To my knowledge, only one coach has been so converted to this point in time.  Conversions done in the 1980's and 1990's did not have this engine as a choice as it wasn't manufactured until 2001. 

FMC's did not have a diesel originally as the smaller diesels that would fit into the coach at that point in time were "dogs" as the former FMC Motor Coach Division Sales Manager has stated.  They would not provide the performance characteristics the designers were looking for so the Chrysler 440-I was the engine chosen.  It was a good engine then and it continues to be a good engine to this day.

Converting a coach is not a small undertaking!!  It is inappropriate for the vast majority to even consider.  They should just drive their coaches and enjoy!  For a few though, the positive features of a good diesel conversion outweighs the cost and trouble of going through the conversion process.  Personally, I have been balancing on the edge for some time.  I have reached the point in my life where I needed to either do it or abandon all thoughts of doing it.  I tipped over to the "do it" side!

At present, the coach is still in my driveway and the donor vehicle (pictures in the album section) is in Gilroy at a fellow FMC owner's home.  He has a larger driveway!  As some of you suspect, the person who so generously is helping (leading?) the way in this project is Eric Whedon, #587, and he is also host of the Northern California Work Days (you need to seriously consider being at the next one!).  His expertise in electrical and computer control systems in addition to his mechanical abilities is what is going to make this project doable as this is a computer controlled engine and a computer controlled transmission.

I want to stay away from cost issues during the project, but will be maintaining a detailed cost and labor record so at some point cost figures will become available.  We also intend to keep a detailed photo and written record of the what and how of what we do.  This will also be available later to help guide someone else should they want to follow the same path.

For now, wish us luck and stay tuned!!!

Terry, the transmission adds a couple of hundred pounds fairly close to the centerline of the rear axels.  The engine adds 100-150 lbs further back.  The overall length is about 1-2 inches longer than the stock setup.  The replacement radiator should be lighter than the stock one and will counteract some of the weight increase.  This is particularly good since that is weight that is further back and has greater positive or negative effects.

This setup has a lot of aluminum in all of the components so it is the lightest diesel/transmission combination that is available.  For comparison, the DD 8.2TD with transmission adds about 800-1000 lbs. In my specific case, I already switched to the AT545 transmission from the 727 a number of years ago and gained that weight at that point in time. 

My new transmission and bell housing will actually be lighter than the one I am currently using.  So in my specific case, I may have an actual net reduction in weight after the radiator is also taken into consideration.

Close enough for me.

Since my last posting, work has continued with interuptions for family matters and weather as we are working outside.  We are ensuring that we properly identify everything that is removed or disconnected so that anything that is to be reused will be clearly identified.

I have posted more pictures in the album section with descriptions of what is being done.  The engine's actual removal from the donor will happen in a couple of weeks, weather permitting.  Then it will get even more interesting.

The work progresses.  The transmission lines, driveline, etc. have been removed.  We then moved up into the cab and finished removing the interior stuff such as seats, center console and floor mat all of which have been sold.

That opened it up for the disassembly of the dash to begin so that the guage cluster, throttle pedal assembly and body control module could be removed.  More pictures have been added to the photo album.

Yes.  

We are doing a "full swap" to the extent possible in this case.  You could do a "minimal swap" which would not involve the dash cluster, etc. and with that swap you would retain the original guages/dash.  We are doing it as the full swap so that the benefits of the full guage cluster and the Driver Infornation Center (DIC) would be retained.  This includes cruise control.  The exisiting systems on all non-computer controlled engines will not work as there is no linkage for the cruise control to attach to.

An example of the two levels of conversion are like what we are involved in right now when it comes to the engine fan.  The donor fan will not work as it is a puller and not a pusher fan.  It also has an ambient air (exiting the radiator) thermal viscous clutch to control fan speed which also will not work as the air is going the opposite direction and will never engage the fan.

The simple solution would be to just remove the clutch and bolt the fan, by using an adapter, to the idler and have the fan operate at engine rpm the same as our fans do on the 440, 8.2, 5.9 etc.  The drawback to that simple solution is that the fan is always drawing full horsepower for the given rpm and, therefore, energy and fuel.

In an attempt to improve on that situation and have the fan only operate at the speed needed for conditions, we are currently looking for a fan clutch/controller combination that will electrically control the fan speed via a viscous coupling based on engine coolant temperature.  When cruising on flat land in cold weather the fan could operate at significanlty less speed than what is needed on a hot summer day if we find the right combination.  Given the amount of air that the fan will be capable of moving, the difference can be significant over a number of miles.

Stay in touch as we work our way through this project.  Your questions/sugggestions are always welcome.

We we haven't made much progress lately as we are working outside and it has been raining every weekend here in Northern California.  The mountains have 165% of normal snow load!  That has given us time to debate another conversion issue/question.

The question is: Should we move the donor steering wheel and upper steering column as well as the dash instruments to the FMC from the GMC Sierra? 

Changing the column would add the complications of doing that transfer, but would simplify the wiring as the four radio control switches, two DIC switches, shifting switch, tow/haul switch and cruise control switchs would no longer be needed to be rewired or moved to dashboad switches.  The steering wheels themselves are within 1/4 inch diameter of each other.  It would also be nice to have all of those controls on the "smart" steering wheel with the factory lighted rocker switches and their symbols.

Eric and I were fortunate to have Harry Day (and his wife, Sandy) stop by on their way south so that we could visit and debate the steering column question.  After that discussion, I believe we will be adding that change to the list of changes.

My coach will move to Eric's next weekend.  In the following weeks the engine and transmission will come out of both the donor unit and the FMC.  At that point, more pictures will be posted and we may have some more issues to solve. 

See the "For Sale" section of this site for things I no longer need and you may want.  I will be adding things over time.

The project continues.  Pictures and commentary continue into page 6 of the album.

http://www.fmcowners.com/mbbs22/photos/photo-thumbnails.asp?albumid=77&Page=5&sortdir=asc 

That link will take you to page 5 where we finish the preparation and start the actual extraction of the engine and tranny combination.

Thanks Terry!

Work has progressed and now the engine is out and the firewall has been cleaned up.

Pictures of the clean engine firewall are on page 7 of the photo album: http://tinyurl.com/7xt6pro

I also removed the unused Thermosan waste disposal unit and it is pictured there as well.  There is now a lot of nothing in the engine compartment.  The next step will be the lining of the existing firewall with sound suppressing material and then relining the firewall with a new layer of aluminum.

Donor engine extraction has happened!  The following link goes the first of the new pictures:

http://www.fmcowners.com/mbbs22/photos/show-album.asp?albumid=77&photoid=2068

There are a couple of pages of pictures with comment.  You end up in the driver's seat.

Enjoy,