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LesR (142.179.40.69)

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Posted on Tuesday, January 28, 2003 - 12:19 am:   

I would like to know the pros and cons of this change
Henry R. Bergman, Jr. (Henryofcj) (65.194.145.34)

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Posted on Thursday, January 30, 2003 - 1:11 am:   

Expensive for gain. The 8 sounds better than the 6. Rebuilding/replacing the 8V71N with the same much cheaper than repowering with a 6V92TI.

The 6 may be easier on fuel with more power/torgue with much better emissions/less smoke. Resale value about the same.

The choice is yours. For my two cents worth, I would rebuild/exchange the V8 with a like mill. Good luck. Henry
lesr (142.179.40.69)

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Posted on Friday, January 31, 2003 - 12:05 am:   

Henry
thanks for your opinion, its somewhat similar to my thoughts!

i would like to read from someone that has done this change

LesR
Geoff (Geoff) (64.1.0.216)

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Posted on Friday, January 31, 2003 - 12:30 pm:   

Les--

You should tell us what kind of bus you have-- some buses accept the 6V92TA with no problems while others have to be modified to have room for the turbo. Also, the condition of your old engine has a lot to do with whether it is worth it or not-- if your engine is toast and you need a new engine/core anyway, then it makes good sense to move up to a 6V92TA assuming you have room for it. There are a lot of good deals out there on engines, and you can always buy a donor transit (other than a pristine RTS) and use the engine/auto transmission package-- either T-drive or V-drive.

Also, 6V92TA are quieter than the 71's because of their wet sleeves. They still sound good. If you want to hear an engine you should rev up a V12 Detroit!

--Geoff
Bob Gallo (208.190.202.180)

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Posted on Saturday, February 01, 2003 - 1:22 am:   

I've done the change in a 4106 GM. It included a change to auto trans and vastly improved drivability. (at the expense of mileage as I also increased HP to 350) It required fabrication, body cutting, imagination, and patience. Now that I've done it, I would say it isn't hard. Costs more than you think. Whatever you do, match the engine config to the bus. I made the mistake of buying an RTS donor cradle when I should have gotten a Grumman. It would have saved a ton in time and $$ in changes.
LesR (142.179.40.69)

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Posted on Saturday, February 01, 2003 - 3:13 am:   

change 8v71 to 6v92 forgot to say its in a MC5A.

the motor thats in it now has a broken crankshaft at #3 oil chanel, it was inspected by a Detroit shop, they said the crank broke and there was no other damage.

I spoke to the person that converted the coach, he said the motor was tired when he bought it from Cardinal Coach out of Calgary AB.

my thought was to put in a 6v92 and 9 or 10 speed trany

thanks for leting me know what i forgot
RJ Long (Rjlong) (24.127.74.29)

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Posted on Saturday, February 01, 2003 - 3:41 am:   

Les -

The RoadRanger 9 or 10 speeds, FWIU, do not fit in the MC-5 chassis between the frame rails - they're too wide.

Seems the most common repower of your coach model is the 6V92TA with the HT740 Allison automatic. You have to replumb the turbo off to the side of the motor, as the engine compartment's not quite tall enough for it to fit on top, but the components are available. Bump the 6V up to 350 hp, and you'll be a HAPPY camper!!

But it IS more expensive than having your 8V rebuilt. . .

FWIW,

RJ
PD4106-2784
Fresno CA
Ian Giffin (Admin) (64.228.55.121)

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Posted on Saturday, February 01, 2003 - 10:34 am:   

Hi Les,

Although Dave Galey's "Big Engine is Big Bus Fun", which you can find in our Articles of Interest section, is about his personal experiences with a 6v92 to a 8v92 changeout, it may give you a broadbased view of the challenge you are contemplating. A handy list of components which will require attention is also presented.

Good luck - let us know what you do!

Regards,

Ian Giffin
www.busnut.com
chris (12.91.168.145)

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Posted on Wednesday, February 05, 2003 - 9:06 pm:   

my 5c has a 6v92t the turbo fits on top if you raise the blower deck
chris

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