4104 engine/tranny combo

[TedsBUSted]

But wasn't 4106 tough on the differential and now that's about the toughest to find?
Or is it the same carrier as an '04, with just a different offset to the housing?

By the way, with the T-drive conversion driveshaft angle problem, I of course meant when changing to a conventional carrier, but you all knew that.

I agree that any conversion is tough. There has to be a lot to gain to make it worthwhile.

Ted

[luvrbus]

The City of Los Angeles Flxible Metros V drive buses had the LTA 10 Cummins and DDEC 6L71 other cities had the same setup the DDEC 6/71 is a smooth set up in a 4104


good luck

[TedsBUSted]

The City of Los Angeles Flxible Metros V drive buses had the LTA 10 Cummins and DDEC 6L71 other cities had the same setup the DDEC 6/71 is a smooth set up in a 4104


good luck

Those sound like a good and workable plan.

Luvrbus - Do you suppose the swaps would require an axle  housing change to keep shaft alignment with the carrier?

If so, would the somewhat "fast" '04 pig fit the "city" or other housing?
Or is the '04 diff already close to its max torque limits anyway?  

I guess the devil's in the details, huh?

Ted

[luvrbus]

Ted I have no idea where the 2 found the rear gear ratio but both have a 3:53 rear ratio some guys say that was never a option for the 4104 and people in the know (who really know) say it was a factory option so you knows both will move down the road for sure and both are set at 330 hp and average 10 to 13 mpg 


good luck

[TedsBUSted]

Wow! Push-start turnpike cogs.  

I heard of a fast "mystery cog" from a traveling vendor who used an '04 for years and seemed familiar enough with 'em. I've recently seen 3:70s advertised, but I sort of wrote it off as a mistake.

3:50 is so tall I can't imagine how the old arrangement would pull it, unless the diff started out in some oddball planetary hub application, or Hall-Scott 1100 RPM package.   (That's a joke, future reader)

To be clear, I personally don't know for fact about any ratio options and I've seen stranger things, so I can't say.

But the big problem seems to be that the carrier location changed sides starting with the '06, making driveshaft alignment difficult when moving inboard from the original '04 location.

Ted

[Hard Headed Ken]

I used the differential from a 4106. It was 8 teeth on the pinon and 33 on the ring gear, 4.125. I have heard of something like a 3.80 is out there. Even the 4.125 was a little high when taking off on a steep uphill so I don't know if a 3.80 would be a good ideal even if it exists. I used my original housing, the center member is in the correct location for the 6V92 / 730 but you will have grind the opening of the housing to allow extra clearance for the larger ring gear.

Ken

[TedsBUSted]

So, Hard Headed Ken,

Did you use the 4106 carrier to get the ratio, or for some other reason, such as driveshaft fit?
Did the side gears and axle splines match?

Ted

[Hard Headed Ken]

So, Hard Headed Ken,

Did you use the 4106 carrier to get the ratio, or for some other reason, such as driveshaft fit?
Did the side gears and axle splines match?

Ted

I used the 4106 pumpkin, carrier, center member (it's know by many names) to get the correct angle and it just happen to have the ratio I needed. The 4104 has the same axle splines.

Ken

[TedsBUSted]

I used the 4106 pumpkin, carrier, center member (it's know by many names) to get the correct angle and it just happen to have the ratio I needed. The 4104 has the same axle splines.

Ken

Thanks for the info.
So a 4106 pig is key.
I'll keep the '06 pumpkin in mind as I continue to mentally (at least first) repower an '04.

Ted

[Hard Headed Ken]

I was told that the 4106, 4107, 4905 pretty much anything after 1961 used the same pumpkin. I just happened to find a 4106 first.

Ken

What I should have said is that anything from the 4106 up should work. I can't remember what year that was, 1962 I think.

[JohnEd]

JohnEd,
I remember the guy you are talking about with the 4106. Did he ever post pic's? I wonder how he is doing now? It would be interesting to see how his setup is working today.

Mike,

I recall seeing a pic and the rear end was longer after the drive wheels.  Not a great deal....maybe a few feet...butg longer.  The bus looked good andnhe had racked up a lot of miles and was content with his creation.

Now Clifford has thrown another fly in the ointment.  His post says that a 6l71 can be had in some reasonably stock version where the DD gets 330 HP and 12 or 13 MPG.  If I could do that I wouldn't dream of going to the trouble of a "conversion".  330 is enuf!  In a 4106 or 4 anyway.  And I have a sneaky suspicion that there is more power to be had without much trouble/cost if the 330 was sanctioned by DD.  Converting the engine is a monumental undertaking and I have only heard of folks doing it to get more power and better MPG.  What I seem to have gathered over these years is that a "fresh" DD is pretty economical and even in power boosted trim they do OK in the HP/MPG category.  If that 671 got 330 from a turbo and such then what is the problem with lowering the compression another bump and jacking up the turbo boost?  I am learning that the engine stays together but needs overhauled more often at shorter intervals.  Haven't heard an interval that I will live to see expire, however.

The 4106 comes with the 8V71 and Don's answer, when I asked what the max power figure he knows about for the engine might be, was that I could make a wish.  He saw the only problem as getting rid of the heat.  I asked about the 750 HP 8V71s in tanks was that they had a radiator that covered the entire rear of the tank and that it wouldn't work in a abus.  OK, but it seems that with the cooling that can be had from the friggen ocean, they do boost the things to unreal power levels in boats.  What I heard, anyway.

I can tell you this without blinking......I rode with Tom PVCCSS in his 4106 and that thing was a genuine hot rod.  If you are not getting any power or MPG you should think "overhaul" or at least fix the thing.

John

[TomC]

The thing about a 6V-71 compared to a 6V-92 is that they are exactly the same from the outside.  In fact, you can't tell the difference between the two except for the cast in 92 at the front of the block and if you open the valve cover, the wider stance of the lower of the 4 valves per cylinder.  This is why I suggest the 6V-92TA.  You most likely won't use much more fuel (especially if you drive it slowly) and then you have the extra power (which is REALLY nice) when you need it.

As to the ISM Cummins, it is still made to this day as a industrial and marine engine with ratings all the way up to 715hp-but remember boats have the ocean to cool them.  Nothing wrong with running a 4 stroke engine at 2100rpm all day-just will burn a bit more fuel, and many times are run that fast in boats all day also.  Good Luck, TomC