Maybe a DD Series 50?

[Mike in GA]

Bus conversion enthusiasts who may be facing the need to rebuild or replace their two-stroke Detroit Diesels may be interested in the approach taken by several members of the Southeast Bus Nuts, who have turned to the newer, four-stroke DD Series 50.
An article in the current issue of the SEBN newsletter follows the efforts of seven hardy souls who have successfully made the leap to the newer technology. There are a couple of negatives to the switch, most will admit, but there seem to be many more positives.

Click on the link to read the article:

http://www.sebusnuts.org/Chapter%20Newsletters/Newsletter%202015%20Spring.pdf

Mike in GA

[CrabbyMilton]

Interesting article. So I guess the bottom line is that if you can live with the fact that it's a sometimes noisy 4 popper, it's great.
The other concern I may have is that it too is no longer built so that could be a problem many years from now.
I would like to see an article about those that swapped CUMMINS engines in pre 1995 MCI's and RPEVOST's where the 92 and 71 were used.

[Lostranger]

Mike, thanks for posting the link. I enjoyed the article and the rest of the newsletter.

I've long been a fan of the S 50 in spite of the fact that I've never owned one. In 2000, a fellow I know who is a full time Bluegrass musician put one in an MC-9 entertainer coach. Tied it to a 13 speed Road Ranger. That bus could run with any pack and got well over 10 mpg.

Before I was aware of the Gillig H2000LF platform, I looked for a 102-C3 with the intent of swapping a S 50 and a 13 speed. I actually traded for the transmission, but got rid of it after we decided to go Gillig. Our bus has a S 40 with B 400 R. We love the engine and power train, and I'm in the process of getting permission from Gillig to have sixth gear unlocked. Our bus is low miles, but if the engine should require major work, I would certainly consider swapping a S 50. I'd also consider S 60 and a variety of Cummins motors.

I mean no disrespect to anyone when I say that our last bus search never included the possibility of getting another two stroke. Ten years with a 6V92TA was enough such experience for a lifetime. I don't mind buying motor oil by the barrel, but I hate having to carry the barrel with me. Changing a balance shaft occasionally seems almost trivial compared to what we went through.

Best of luck to all who are swapping 2s for 4s. I think it's a smart move.

Jim

[lostagain]

A 4 stroke is nice for sure.

But remember that a DD 2 stroke can be made to run right, and to not leak. I have one, my 6V92TA. You can repair leaks one at a time, and address one as soon as it starts, in order to run a clean engine. And if you keep up on proper maintenance and tune ups, you can have a good running, reliable 2 stroke Detroit.

JC

[sledhead]

I two have a out of frame rebuilt 6v92ta ( 2010 rebuild ) with no leaks and now have 350 hp . Yes I carry 2 x 2gal. jugs of 40 wt oil with me on all my trips and have had no problems .

I see no reason to replace it

dave

[luvrbus]

Like JC I wouldn't pull a good 6v92 (they do not need to leak oil) to make the swap but the price of parts to rebuild a 6v92 you can buy a bus with a 50 series and b400 for around 4 to 5 grand.The 50 series is a fairly easy swap for a MCI being short in length re powering a older MCI you don't have a lot of space to work with because of cooling system. Bruce (bs4104) has a N14 Cummins in his MCI he extended the rear to install it forgot the length of his bus I believe it is around 42 ft now

Not many Eagle and Prevost people do the 50 series about all the Eagle people go with a Cummins,Cat or the 60 series they have the space I removed a series 50 and B400 from a Eagle a couple years ago the owner never liked it driving in the mountains so he went with the Cat  

[lostagain]

If a bus had enough room for a Cat 3406B (mechanical), or E (electronic), those are good, tough engines. I have the B in a gravel truck. And I drive a friend's gravel truck with the E. That would be quite nice in a bus.

I used to drive a 102D with a series 60 and Eaton/Fuller 7 speed manual. That was a great combination, if you don't mind shifting gears. Yes it vibrates a bit at idle, but that is minor. The biggest draw back to me was the awful sound of it, nothing like the sweet note of a 2 stroke.

JC

[Geoff]

I have a 6V92TA rated at 350HP and it already gets 8mpg.  Purrs like a kitten and no oil leaks.  And best of all, it is a mechanical engine so no computer to let you down and cost you the big $$.  Series 50?-- no thanks!!

--Geoff

[TomC]

It also helps that Geoff is a Detroit mechanic! If you're nervous about parts for the Series 50, Series 60 people should be nervous too since neither engine is being made new anymore.
Series 50 is OK, but very tall. If it ever comes to the point I can't run my Caterpillar 3406B mechanical anymore (the most reliable engine ever made, IMO), I would do a complete swap for a Cummins ISL. In RV form it is rated at 450hp and 1250lb/ft torque-more than enough power. The Cummins ISL will be around for a few more years. Good Luck, TomC

[muldoonman]

What could you cram in a 1991 XL Prevost that has the 8V92TA with 755cCr. Mine only has 77,000 miles on it but always looking down the road. Thanks.

[luvrbus]

It's a chore Glen to install any other engine in that model of Prevost the tag axle is the problem but doable Ken installed a 14 L series in his XL working around the tag I think Kent redone his tag to install a Cummins with a automatic both of of those guys can tell you the pit falls and the work involved lol just take care of the 8V92 

[muldoonman]

You bet Cliff. Thing runs great and no oil leaks except a couple months ago had service done at Prevost Houston and they dumped whole case (9 gallons) of Delo 100 I bought with me to change. Blew it out going home, until it hit a little over full mark. Cleaned it up and still no oil leaks, Thankfully. That's what you get for $125 bucks a hour labor.

[bevans6]

Here is the thing about putting an S50 in a MC-9 or equivalent.  Start with the fact that the engine you have, the 8V-71 or the 6V-92TA, is worn out and needs a refresh at least, out of frame.  Step two is you know some guys who have a bunch of good S50's and you can get one pretty cheap, turned up to 350 hp.  Step three is it fits easily, with the big soft mounts for the vibration, and you have the skill set (or you know someone who does) who can handle the electronics.  Step four is it will run cool and clean with only one of the stock MCI radiators, so you can put in an intercooler or whatever really cleanly.  Step five is you can run faster and harder than you ever could, and get way better fuel mileage than you could with your old, worn out engine.  Step six is, you think it would be fun and a real hoot to do, you have the skills, the tools and the mindset so you do it.

I met and spoke at length with the guys from the SE Bus Nuts when I went to Palmetto, I think there were two or three MCI's with that conversion, and all were extremely impressive.  I took detailed measurements to see if I could put one in my MC-5C.  It would have fit, barely (like 1/2" clearance to the valve cover), and I looked into it.  It would have cost me about $15K so I put it on the shelf.

Cheers, Brian

[lostagain]

Is the S50 heavier than the DD 6V92, or 8V71 ? If so, how would the MC5 rear frame structure withstand that weight?

JC

[luvrbus]

The series 50 is about 150 lbs heavier than a 6v92 and about the same amount lighter than a 8v71 just ball park figures the best I recall