DDEC engine into non-DDEC bus? how hard?

[bevans6]

So, if I was to look for and find a nice 6V-92/Allison 740 take-out and put it in my bus, how hard would the conversion from non-DDEC to DDEC be?  I saw a 1996 take-out from a MC-12 on ebay, had the whole package still on the cradle, ECM and tranny still installed.

Brian

[Don Fairchild]

Brian,

   are you asking about changing the engine back to mui or wiring your bus to accept the DDEC engine.

[bevans6]

Hi Don.  Here is the thing.  I now have the old standard - 8V71 and Spicer four speed.  I've been putting together the plan to, with your advice and parts, rebuild the 8V71.  That leaves me with the Spicer - not a problem now, but I do have cartilage issues in my knee so an automatic is always on the horizon.  But - TomC has recommended a 6V91/Allison 740 to me many times so I am always sort of looking for that combo.  I saw one on Ebay today, but it will be a DDEC III, most likely.  I "think" that the DDEC III can run pretty much stand-alone in the bus as long as I add a coolant sensor somewhere, and I have the TPS hooked up somewhere so it can read the throttle position.  so before I buy this engine package, I wanted to make sure I understood if it's possible to run a DDEC III type of engine in a bus that had a mechanical in it, without having to break the bank on inventing stuff or rewiring the whole bus.  I just have never researched the whole DDEC concept to the point where I understand it well enough to make an informed decision on this sort of thing.

Any and all advice is appreciated.  To answer your question directly, I am asking about transplanting a complete DDEC III type engine/transmission combination into a bus that now has a MUI 8V71.

Thanks, Brian

[lostagain]

The 6V92TA/HT740 in my MC5C is all mechanical, so there must be others to be found.

JC

[bevans6]

JC, I take your point but in a year of looking I haven't found  a good take-out MUI 6V92/740 from an MCI yet.  I have found this one...and it's probably 15 years newer than a mechanical will be.  If it can work, I may be interested.  If not, I will have learned something!

Brian

[luvrbus]

And  for sure you want one from a MCI I changed a 8v92 from a Eagle over to a MCI not a fun job MCI did some crazy stuff


good luck

[lostagain]

I agree with you Brian, a DDEC engine in good shape would be great. There are good and bad things to either, mech. or electronic.

You would have to get all the computers and associated wiring that come with the engine and tranny and transfer everything to your bus. I don't see why it wouln't work.

Mine has the turbo mounted on the driver's side. The pass. side exhaust pipe comes around the front of the engine from the manifold to the turbo. Then below the turbo is the air intake filter, and the muffler. Makes for a crowded engine bay, which was intimidating to me at first, but it really doesn't take any time to remove this or that piping to get at other things behind them.

Having the turbo above the engine is pretty well out the question in a 5, unless you want to get into major customizing of the rad blower assembly to make room for the turbo.

I could take some pics. and post them if you want to see.

JC

[luvrbus]

On my 5 I mounted the turbo on the rear, the side mounted turbos are a little lazy( slow to spool up) you need to keep the pipes as short as you can for faster spool up and less smoke, Brian if you buy a DDEC buy a IV if you can I am pretty sure Sam will have a harness that will work for you
Not a lot of fun to make one for the transmission and engine


good luck

[TomC]

I would try my hardest to find a mechanically operated engine and transmission.  Granted the electronic engines do have some nice features and do get better fuel mileage (about .5-1.0mpg better), but with the headache of installing all that wiring, the electric gas pedal and electric shifter, and the fact that you need to have only one break down that requires a tow that would completely wipe out any fuel savings you would have had.  There is nothing more reliable then the mechanically operated engine and transmission-period Good Luck, TomC

[artvonne]

and the fact that you need to have only one break down that requires a tow that would completely wipe out any fuel savings you would have had.  There is nothing more reliable then the mechanically operated engine and transmission-period Good Luck, TomC

  No truer words can be spoken, and you dont ever need to own a bus to know it. Ive always felt that electrical engineers have something against mechanical engineers, they always try to find a way to add complexity to things that worked perfectly fine before they started monkeying around with them. I have already read several threads here about busses shutting down from simple sensor failures, or not surprisingly, entirely unknown reasons, and thats all fine and great if you cant fix anything yourself or dont have the knowledge to be able to judge when to shut down your own engine. From nothing other than a safety standpoint, being able to get your vehicle off the road, or out of harms way, even at the cost of engine damage, is to me far more important than having a computer think for me.

  A better example is modern aircraft. The industry is forever trying to increase profits, so putting glass panel displays that completely do away with all mechanical instruments (and the labor to install them) has become more and more common. Where before you had seperate instruments, whose failure had nothing in common with any other instrument, and virtually nothing tied to the electrical system, today EVERYTHING is tied to one instrument (the panel) and it is ALL dependent on the electrical system. A failure of the panel, or an electrical failure will completely wipe out all instruments, effectively making you blind. Having aircraft think for themselves is why we never found that Air France Jet that was lost over the Atlantic.

  A diesel with mechanical injection does not need an electrical system to run, only to start (and with air start or a pony engine, not even then). A mechanically operated transmission, whether manual or auto, will also operate without electricity. All computer and electrical controls do to a motor vehicle is make them far less reliable IMHO.

[bevans6]

"All computer and electrical controls do to a motor vehicle is make them far less reliable IMHO."

I couldn't agree more, which is why I am very nervous about this idea of putting in an electronic engine.  But what they also do is control the engine in a far finer way, so improving economy and emissions.  On one engine, the improvement in economy is moot, and the improvement in emissions is "who cares", over fleet and a country, both are significant.

At the end of the day there is a 90% chance that I will have an 8V71 in there, same as there is now, just hopefully not spewing oil all over the countryside.  But while that is no doubt the route I will take, I am uneasy enough about it being the BEST route that I cannot stop myself chasing down any and all options that present themselves.

Brian

[TomC]

Currently, in California at least, RV's are exempt from smog laws.  So my '85 Kenworth with the Caterpillar 3406B 400hp is OK.  But-knowing California, they will eventually change that ruling.  When they do, I'm not going to fool around.  I will go all the way and install a Cummins ISL 450hp RV rated engine with 3000MH Allison with all the smog controls up to date.  Quite possibly, it maybe cheaper to just buy a new truck!?  Good Luck, TomC

[kyle4501]

Currently, in California at least, RV's are exempt from smog laws.  So my '85 Kenworth with the Caterpillar 3406B 400hp is OK.  But-knowing California, they will eventually change that ruling.  When they do, I'm not going to fool around.  I will go all the way and install a Cummins ISL 450hp RV rated engine with 3000MH Allison with all the smog controls up to date.  Quite possibly, it maybe cheaper to just buy a new truck!?  Good Luck, TomC

May be even cheaper to move to another state!   

[Don Fairchild]

Brian,
 
  Basically it takes 9 wires to run a DDEC. you will have two hots, one will be direct to the computer the other will be thru the ignition one ground and six from the throttle pedal.You will need to add a low water sensor. From their you can add cruse, two stage Jake's and what ever.

Hope that helps

Don