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Jim Cram

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Posted on Tuesday, November 30, 2004 - 8:26 pm:   

Ihave an MC9 with an 8v71 and am considering
going to an 8v92 any one out there done that or have any comments thanks in advance jim
TWODOGS (Twodogs)

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Posted on Tuesday, November 30, 2004 - 8:48 pm:   

might as well go 4-stroke...425 cat would be fun
Bill K.

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Posted on Tuesday, November 30, 2004 - 9:17 pm:   

Jim go for it, you will love the power, but keep in mind that you will need the larger radiators if you don't already have them and also the larger fans, there is also some other changes but the 92 is more plentiful then the 60 series and a lot cheaper to make the change, I have said before that if I had to do it over again, I would have rebuilt and turbo. the 8v71, a lot cheaper and easier.
Buswarrior (Buswarrior)

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Posted on Tuesday, November 30, 2004 - 10:12 pm:   

Hello Jim.

If your heart is set on more power, you have ample cash, and you like a challenge, then you have my support, and I say go for it!

But, if you aren't sure yet, a friend of mine and Bill G's, has had a devil of a time doing an 8V92 into an MC8, same as an install into most MC9's.

Grabbing a truck motor is not for the faint of heart. There are unique engine parts to buses, which are hard to find, or you pay MCI a lot for them.

Even with the bigger fans, and cutting the rad compartment skins to fit in the 102 radiators, if you dial that engine up to the 450 or 500 HP settings, you'll have to know what you are doing with the fuel pedal on a big climb, or you'll overheat it.

Which is great fun for some of us, and a real crisis for others of us. Depends on your demeanor.

For your consideration:

I've been to the well of modern power and I have taken a big drink....

Yes, big power is fun, but when measured objectively, well, the fun isn't that big, costs a lot, and takes all the skill out of the journey, if you know what I mean. Not nearly the same amount of thought required to drive the new cars.

My MC8 conversion with stock 280 HP 8V71 climbs at 44 MPH the same hill in West Virginia that a new seated coach MCI EL3 Rennaissance with 400 HP Series 60 climbs at 50 MPH.

In the MC8, if you don't pay attention and get the next gear at the top of the governor, well, the momentum is lost, and it'll be a long climb. That darned Rennasssiance will recover from all manner of poor driving, recovering speed on the hill, so any goof gets up the hill almost the same as the most experienced pro!

So, whatever it is that motivates you, and lets you enjoy the journey, pick the options that make you happy!

happy coaching!
buswarrior
ChuckMC9 (Chucks)

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Posted on Tuesday, November 30, 2004 - 11:35 pm:   

Buswarrior, could you take us thru this sentence again, in slo mo?

"In the MC8, if you don't pay attention and get the next gear at the top of the governor, well, the momentum is lost, and it'll be a long climb."
Derek (Derek_l)

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Posted on Wednesday, December 01, 2004 - 12:11 am:   

Chuck, I'll take a stab at it, as Buswarrior might take a day or two to respond..

Driving the standard, you've got to watch for your shift point.. Say, 4-3 is 45MPH, you'd better start shifting at about 48~49MPH to get into 3rd at 45, otherwise you're going to be trying to accelerate up the hill.

As was pointed out, with a 400 horse Series 60, no problem. With a 300 odd horse 2 stroke, with RPMs dropping, you might have to go to 2nd and watch the scenery drive by that much slower.

Same thing with an auto.
ChuckMC9 (Chucks)

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Posted on Wednesday, December 01, 2004 - 12:31 am:   

Thanks, Derek! All I needed was a little rephrasing. So basically start downshifting early so that you're sure you're in the lower gear before the beginning of the grade. And yes, I have a crashbox but haven't tackled any serious grades yet.
RJ Long (Rjlong)

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Posted on Wednesday, December 01, 2004 - 12:39 am:   

Chuck -

Go to the BNO home page, and in the "Articles of Interest" section, read the article about shifting. It will explain what Buswarrior and Derek said in a little greater detail.

HTH,

RJ
PD4106-2784
Fresno CA
Ron Walker (Prevost82)

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Posted on Wednesday, December 01, 2004 - 11:43 am:   

Jim, if your heart is set on it and you have a line on a good silver 92, I would go for it. I just changed my 8V71 with a silver 92 ta and what a differance on the hills, I live in mountain country. I bought a truck motor and had to modify the rear motor mount brackets off the 8V71 and modify the truck front motor mount to fit the bus. It took about 20 hrs labor to get it button in. A friend down the street put one in his MCI9 and it took around 30 hrs to get it in and running. You have to set the 92 up the same as your 71 was, fuel lines, heater hoses, air line ect.

It's a lot less work that trying to put a cat or S60 in....that's a lot of work and money.
Ron
ChuckMC9 (Chucks)

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Posted on Wednesday, December 01, 2004 - 11:45 am:   

Oh, RJ, I've read your excellent article several times and have a printout in the coach. Am getting pretty good with 'normal' shifting just always on the lookout for the finer points. Many thanks for the reminder tho - a good reread is a great idea.
Bill K.

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Posted on Wednesday, December 01, 2004 - 1:05 pm:   

Well I want to tell you that it took me a whole lot more the 30 hours to make the change, First move the rear mounts and make a new front mount, different front crank pulley, shorten the drive shaft 1". change the tork convertor. up grade the air cleaner for more air, change the muffler 5" in and 5"out. different radiators, and different fans. then linkage had to be changed because the turbo was in the road. different flex plate. Different adp for the Alt. And there is more this is just off the top of my head. this change was in a mc8.
Ron Walker (Prevost82)

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Posted on Wednesday, December 01, 2004 - 2:15 pm:   

Hi Bill, friend down the road didn't change the rad's and fans and is running a 4 speed gear cruncher, it bolted right up to the 92. He added a mister for long hill climbs but lonely uses it on hot days is the summer, 90 deg's +. He's been running it for 5 yrs, as a charter.
Ron
Ron Walker (Prevost82)

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Posted on Wednesday, December 01, 2004 - 2:32 pm:   

Sorry, forgot to mention we are in the interor of BC, lots of long steep grades. Ambient temp's can reach 110F in the summer. So very similar to the SW desert area
Ron
John Rigbyj

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Posted on Wednesday, December 01, 2004 - 6:10 pm:   

My friend change his MCI9 over to a 8v92 no problem. Like Ron said he had to make a new rear mount and bracket. He loves the extra power. He can beat my 4104 on the steep grades now. I am not used to that.
John
Buswarrior (Buswarrior)

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Posted on Wednesday, December 01, 2004 - 10:32 pm:   

Hello all.

Yes, Derek and RJ caught my intent.

If you don't get that gear change done at the right time, the engine will be falling down out of the power band again, by the time you get it pulling again.

Now, not the end of the world, but it is nice to get all of the little power you have available, if that turns you on.

It requires little driver attention or skill to drive the big engines.

It requires more attention to get the best performance out of an older, less powerful engine.

Whatever it takes to stay awake and happy!

happy coaching!
buswarrior

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