Engine Ponderings from a different angle..

[kjurkic]

Howdy all

I don't post much; just bought a '94 RTS, not to convert right away, but to run a small charter operation for a few years. If it succeeds I will buy a newer bus and retire/convert the RTS. If it fails, I will retire/convert the RTS

Anyway, as I was driving the bus (DD Series 50, with Allison V730R) I was pondering possible future repower, especially after a long, slow uphill grind. It seems the only power-up option due to V-Drive is finding someone with DDEC tools to re-program the existing engine to gain a bit. While it seems that parts for the S50 are not prohibitively expensive, if the balance shaft assembly ever snaps, that part could really break the bank.

Since there is no room for an S60 or other heavy duty engine, I began thinking of smaller dimension power-plants. I know that the Ford 7.3 is smaller and lighter over-all, and there is a strong aftermarket where builders are getting more horsepower and similar torque as my S50 - with the added benefit of ability to spin to 2800-3000 RPM. Recent experience with a 2000 F550 with this engine has been very positive for me.

As I dug into this, I found that the most recent PSD from Ford, the 6.7, is STOCK @440hp/860tq, while being cleaner, quieter, and more fuel efficient than my 20yr old DD. Its rated to 40k-lbs GVW (truck-trailer combo) The GVW on my RTS before I down-rated the seating capacity is 36K-lbs.

Then that begs the question of whether the Alison 730 can play nice with a different engine?

I understand that the DD S50 engine is very understressed, and good for 500k miles between overhauls, where a smaller engine would be lucky to get to 250k miles - however I am in an area where I can easily find second hand Ford PS diesels, but Detroits are "Hen's Teeth"; not to mention killer shipping costs.

I have also seen discussions here and elsewhere about converting from V to T drive; I would think a dimensionally smaller engine/trans would make this swap possible, plus many of the newer Ford/Dodge/GMs come with 6 speed autos. Just wondering if anyone has broken out the tape measure and went Hmmm?

Cheers
Ken

[HB of CJ]

It might just be cheaper to find and buy a bus that will work better for you?  Re powering with a different engine, even if possible, usually takes a great deal of time and money.  Curious:  where are you located?  Welcome to this Excellent Bus Conversion Forum.

[kjurkic]

Howdy

They were just ponderings; I am located on Vancouver Island, west coast of Canada.

Unlike the U.S., finding a bus on Canada's west coast is very difficult; with the current exchange rate, brokerage, and other import costs, buying from U.S. is a non-starter.

There are very few RTS's in Canada. I really like the look, and it drives much easier than I expected.

Cheers
Ken

[MB LeMirage]

I too have wondered about this same thing. My concern was that while yes it is rated to pull a max of 40000 it is probably not rated to do it all day every day. The life span may be greatly reduced. Also the stresses of powering  a 40ft vehicle compared to an 18 ft'r might be the reason for heavy castings and re-enforcing found on commercial diesels. Might a modern small disp/high power block not survive the stresses involved?
But still an interesting idea for any engineers out there to ponder and muse upon.
Ryan.

[blue_goose]

If you turn the power up it will be all the RTS needs.  The first thing you need to check is the Air to Air and make sure there are no leaks.  I have driven the RTS's with series 50 and when they are tuned up they have plenty of power. 
Jack

[luvrbus]

Turn the series 50 up to 375 hp it will do good and they give a warning when the balance shaft is going bad it gives you ample time for repairs just watch the oil pressure

[kyle4501]

Engine swaps seldom come in under budget - always seems to be more to it than planned.

If you would take the money it would actually cost to do an engine swap & put it in the series 50, you will have a very healthy & happy power train and likely have money left over.

[kjurkic]

Thanks all

I do know the best power adder for an old vehicle is making sure everything is tuned to spec.

I am hoping to get it into a DDEC specialist sometime in next few months to see about a once-over to ensure all components up to snuff.

I have a couple of long uphill grinds on the routes I am planning to charter over, walking speed ain't quite enough for me

Just spent last couple of days re-configuring seating and luggage racks for better layout. I am really impressed with the design/build quality of the RTS. I was expecting to have to use the angle grinder to remove old bolts, but only needed some release-all and elbow grease due to all stainless hardware.

cheers
Ken

[TomC]

I turbocharged and air to air intercooled my 8V-71. Used 7G75 injectors for 375hp and 1125lb/ft torque (was dynoed). The bus really charges up hills now. Pulls the Grapevine 15mph faster than when non turbo'd. Only have to down shift on big hills. I say this, because I know you'll be satisfied with the S50 if you just turn it up. The S50 at 375hp will put out more like 1230lb/ft torque. If you have problems with the V730 slipping, just have a transmission shop bump up the valve pressure a bit. Mine was modified and shifts just fine under full power. DON'T change that engine. The S50 is just about the most perfect RV engine you could ever want. Good Luck, TomC

[Scott & Heather]

Yeah, a handful of gents at the Arcadia rally swapped 50 series into their coaches


Sent from my iPhone using Tapatalk

[Detroitenginespecialist]

Ken,
American Fleet is a Detroit Diesel engine specialist.  We specifically build Detroit engines for buses.  Not only do we build 20 Series 60 a month, we also build a few Series 50 each month as well.  IF you'd like, please give us a call with any questions you might have.  We can also sell you parts if we have them. 

Right now we are in the middle of building a few Series 50 for a transit company out of Florida that runs buses for Disney World.  We will be re-manufacturing 10 this year for just this one customer.