8v92 upgrade

[cutnhorse]

was thinking of using the rad from the donor firetruck the 8v9e motor comes from its a mechanical 475 horse , using a gear box from a prevost fan, anyone know if the prevost gear box is a 1:1 ratio, using the fan from the firetruck

[Bearmtnmartin]

I am almost finished a repower. I did every single thing myself and am up to around $30,000. I am OK with that but I would never tell my wife, and the only way I could have saved money is to build some garbage I would not have been proud of.

[RJ]

was thinking of using the rad from the donor firetruck

That radiator is fine for a truck with the radiator out front.

It will quite possibly be too small for a side-mounted bus application.

The radiator on my 8V92T Prevost is 3' x 3' x 7" thick - and I STILL have to closely monitor the temperature gauge climbing 6% grades.

But it's your coach, your money, so do it your way. . .

[windtrader]

These major heart transplants were sometimes done in the early days of the growing bus conversions fad. In 2020, it is more economical and time-saving to start with a Series 60 bus. They are selling for dirt cheap and would be a far better platform for a new conversion.


There is no free lunch. Sell the MC8, use that to get into an already converted Series 60 bus. Yes, you will have to pony up some extra dollars but it will for sure be less than what you sink into the engine upgrade. You can buy an unconverted bus for less than a converted one, saving you money upfront. Then pay as you DIY conversion. Sill takes time and money but you control both variables. In the end, you get a much better bus platform and a new interior.

[cutnhorse]

rj
  do you know if your prvost is running a fan clutch or does it have a old school fan with no clutch? good point on the fan  not having air pushed through.

[Jim Blackwood]

These major heart transplants were sometimes done in the early days of the growing bus conversions fad. In 2020, it is more economical and time-saving to start with a Series 60 bus. They are selling for dirt cheap and would be a far better platform for a new conversion.


There is no free lunch. Sell the MC8, use that to get into an already converted Series 60 bus. Yes, you will have to pony up some extra dollars but it will for sure be less than what you sink into the engine upgrade. You can buy an unconverted bus for less than a converted one, saving you money upfront. Then pay as you DIY conversion. Sill takes time and money but you control both variables. In the end, you get a much better bus platform and a new interior.

This is the route I decided on when I bought my bus. Too many advantages to overlook. I've done engine conversions on quite a few smaller vehicles and would have no reason to shy away from one of these but I also know how the domino effect takes over despite your best efforts. The schedule stretches out, the cost goes up, and it takes years to get the performance and driveability you expect to have. Not for the faint hearted, one modification can and usually does cause even more mods on down the line.

Flathead Fords are another older engine that has a great sound and vintage appeal but you rarely see anyone using one as a daily driver or these days even as an occasional driver. Low power, piss poor mileage, overheating issues, any of that sound familiar?

Jim

[buswarrior]

Do remember, most busnuts look at this mountain and wonder why anyone would climb it...

Because it is there?

If you want to engineer the dream drivetrain for that bus... is the advice from places that still have enough moxy left to do another one, or is it from places that are too tired, or never would have in the first place?

We can be such a bunch of downers, with all our sage advice...

Climbing rocks makes little sence except to rock climbers.

Build it!!!

Happy coaching!
Buswarrior

[CrabbyMilton]

We all like the sound of those old DETROIT engines as well as our favorite car and light truck engines. But we have to remember, sentimentality and nostalgia doesn't propel vehicles. Yes, the old DETROIT 71 and 92 as well as the mentioned FORD FLATHEAD V8 and others were good. But you always have to ask that if they were all that good, then why don't they build them today? My very first car was a 1972 AMC MATADOR with a 5.0L V8 and 150HP. My current car a 2021 NISSAN ALTIMA has 2.5L 4 with 188HP. Plus, these new 4's aren't the noisy and crude engines of 30-50 years ago.
Same with buses. The last coach I was on was a 2020 J4500 with the CUMMINS. At idle speed it hardly had any vibration compared to those earlier CUMMINS and DETROIT S60's from back in the 1990's.

[luvrbus]

Cummins has a special build ISX 12 for bus use and they are smooth and quite,my ISX 15 is not quite or smooth on idle,the old 8v71 or 8v92 Detroit are really smooth on idle 

[Utahclaimjumper]

 My pre electronic Cummins C 8.3 is rated at 320 horse,, about the same as a 71 or 6V92,, but has over 900 foot pounds of torque!!  Put this with a 6 speed allison and the match is great without the hassles of older or more modern combo's..>>>Dan  (The side mounted radiator is cooled via a hydraulic fan motor that simplifies the install,, the hydraulic pump is gear driven on the engine and also serves the power steering.)  ( A great upside is 10 miles per gallon.)

[RJ]

do you know if your prevost is running a fan clutch or does it have a old school fan with no clutch?

No fan clutch, direct drive with a nine-blade Horton nylon cooling fan.

[luvrbus]

Prevost with the 4 strokes have a fan clutch

[TomC]

Except for increasing the power on a 8V-71, I wouldn't waste my time, or money at converting to a 8V-92TA. All 2 stroke Detroits are disappearing-along with the mechanics to work on them. This is one of the big reasons I converted my '85 Kenworth with Caterpillar 3406B (3406C mechanical is still being made).

The engines that I would convert too would be a Cummins ISM (still being made), Cummins X12 for a smog engine. A Caterpillar C12.
The Detroit Series 60, Caterpillar C15/C16/3406, Cummins X15 are all big block truck engines and are not necessary to move a bus down the road. Good Luck, TomC

[TomC]

Utahclaimjumper-900lb/ft torque sounds like a lot of torque-granted it is 100lb/ft higher than the 8V-71N. But consider that the high end motorhomes now with Cummins X15 are putting out 1950lb/ft torque-no comparison in performance. Good Luck, TomC

[Utahclaimjumper]

 Tom,, My friend has a new 6.7 Cummins in his Ventena that comes in at 45K loaded , this engine is rated at 360 horse and makes very little more torque than my 8.3..  It moves that coach very well..>>>Dan ( It really isn't necessary to feed a monster all the time.)