Author Topic: My "new" challenger  (Read 4953 times)

Offline Lin

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My "new" challenger
« on: November 13, 2007, 10:10:45 PM »
Howdy,
     It has been a couple of years since I posted here.  At that time I only had my 1967 Superior w/ the Toroflow engine.  I still have it but have not driven it much although it is in fine running condition.  Anyway, I just bought a previously converted 1965 MCI 5a Challenger.  The conversion was probably somewhat professionally done a long time ago.  The former owner took good care of the house side, but there seems to be a reasonable amount of deferred mechanical stuff.  There are a whole pack of air leaks.  After fixing several of the moderate ones, the bus will hold some air for almost 20 minutes now!  One of the problems I am trying to solve is a problem with reverse.  I have an 8v71 with a 4 speed Spicer.  When I put it into reverse, the bus bucks and jumps.  You have to get off the clutch fast to stop it and can not use it for control without it bucking again.  The former owner believes it should do that; sounds nutty to me.  I know the clutch probably needs some adjusting, but doubt that will solve that problem.  Any ideas?  Another immediate issue is that the high beams on the right do not work.  At first it was only the high beam light itself which I took off to try to get the part number (24volt) to order one at a parts store.  However today I found that the high beam on the low beam light is not working either.  I guess I may have done something while fiddling with other stuff.  Is there an obvious answer for that or do I have to start tracking wires.  Another question:  There is no tach and I would like to have one.  There is a space big enough on the dash that is circular and has the original group of warning lights on it (low this, high that, lav emerg, etc).  The little red dot lightat the center comes on when the power switch is turned on.  Other then that, I do not know if the rest of it works and wonder if it is worth the space anyway.  Anyone familiar with that that could give advice.  One last thing, is there room to put an automatic transmission behind the 8v71?  Someone told me that it probably won't fit, but I thought I've seen buses for sale that had it done.  All info greatly appreciated.  Thanks, Lin
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Offline edroelle

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Re: My "new" challenger
« Reply #1 on: November 14, 2007, 05:29:53 AM »
In an MCI 5, you can either put an Allison 640 series behind an 8V71, or I think some have put an Allison 740 behind a 6V92T - which would make a nice powertrain.

Ed Roelle
Flint, MI

Offline Stan

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Re: My "new" challenger
« Reply #2 on: November 14, 2007, 05:47:58 AM »
First off, if you don't have service manual and parts book for your bus, get them.

The MC-5A 24 volt headlight system is straight forward. Power goes from the headlight switch to the dimmer switch and then to the left headlights. Jumper wires across the front of the bus to the right lights.

The indicator panel in the dash has a lot of information. Along with low air pressure, low oil pressure, high water temperature, it has indicators for brake lights and signal lights that don't come on if you have a light not working (burned out bulb). Put your tach somewhere else.

You can put a 600 series Allison (644 or 643) between a 8V71 and the drop box but not a 650 series.

I can't help you on the reverse clutch problem.

Offline DavidInWilmNC

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Re: My "new" challenger
« Reply #3 on: November 14, 2007, 07:05:18 AM »
My headlights have been converted to 12 volts (I'd recommend this for ease of bulb replacement).  I started getting weird things like one high-beam would work, the other side's low-beam would work, etc.  It turned out to be a bad connection.  The plug that connects to the back of the bulb itself  was (and still is) old and slightly corroded.  I need to replace all of those sockets - thanks for the reminder!  I found it by jiggling the wires while the bezel was removed and the bulb was loose.  As to the reverse problem, I know revers is a fairly high gear and not particularly easy to control on my MC-8.  It's like it's either on or off ... not controllable like in 1st.  It kind of reminds me of starting out in 2nd gear.  A tach sure would be nice (so would the automatic trans); I'm thinking about adding one at some point, too.  Good luck with it!

David

makemineatwostroke

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Re: My "new" challenger
« Reply #4 on: November 14, 2007, 07:30:20 AM »
Lin, the 644 Allision will not bolt up direct to the bellhousing on a 8v71. i did this set up 11 years ago on my MCI 5 that I had  and by the time that you buy the adapter ring,the spacer ring,flex plate,drive shaft ,yoke and shifter tower and cable it cost a couple of thousand dollars plus the transmission.Like Ed said the 6v92 and 740 would be the best bet being that the set up is easy to find at a good price now.I did not like that 20mph reverse is why I changed

Offline Lin

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Re: My "new" challenger
« Reply #5 on: November 14, 2007, 08:14:30 AM »
Thanks for the info so far.  It appears then that the reverse was designed to be extreme then.  What does a swap to 6v92 + 740 cost?  This 8v71 is supposed to have had a recent top end rebuild and seems to run beautifully.  It would be a shame to waste it. 

Does anyone know a good bus mechanic in the Santa Cruz/ San Jose, CA area?
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Offline TomC

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Re: My "new" challenger
« Reply #6 on: November 14, 2007, 08:53:52 AM »
The jumping and bucking in reverse maybe a clutch problem, but more than that a broken engine mount the torques up in reverse, but stays put in forward.  Good Luck,  TomC
Tom & Donna Christman. '77 AMGeneral 10240B; 8V-71TATAIC V730.

Offline RJ

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Re: My "new" challenger
« Reply #7 on: November 14, 2007, 09:25:46 AM »


Does anyone know a good bus mechanic in the Santa Cruz/ San Jose, CA area?


Lin -

Go see Dan Smith at Royal Coach Tours in San Jose.  Their office/yard is on Stockton St, just south of Taylor.  Dan runs one of the finest charter bus outfits in the Bay Area, and is an avid busnut, too.


As for reverse - remember, these things were really only designed to back out of a flat parking stall at a bus terminal, not the kind of use bus conversion folk tend to have.  Lots of fine clutch control is essential.  However, you still might have the powertrain checked for bad motor mounts, or you could have oil on the clutch disc, causing grabbing.  Does it grab in 1st, too?

FWIW & HTH. . .

 ;)
RJ Long
PD4106-2784 No More
S13406 1978 MC-5C Converted 6V71/MT-644
S14947 1980 MC-5C Shell 6V92/HT-740
Cheney WA

Offline Tony LEE

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Re: My "new" challenger
« Reply #8 on: November 14, 2007, 12:37:16 PM »
"As to the reverse problem, I know revers is a fairly high gear and not particularly easy to control on my MC-8.  It's like it's either on or off ... not controllable like in 1st."

The specs for my MC8 show gear ratios of

1st 4.3
2nd 2.33
3rd 1.36
4th 1.00

and reverse 6.00

so reverse is 50% slower than first???  or am I missing something.

Offline Lin

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Re: My "new" challenger
« Reply #9 on: November 14, 2007, 08:45:50 PM »
This was a good start.  As suggested, the headlight problem was straight forward; just a broken connector.  I don't know why I assumed it would be something esoteric.  I like the broken motor mount suggestion because it makes good sense and will have that checked.  Maybe by Dan Smith in San Jose if I can get over there soon.  I will have more questions coming up, but having this board has made the process much less stressful.  Thanks

By the way, the gear ratio in my 1st is 4.25 and reverse is 4.34.  Apparently, just because reverse and 2nd are in the same place does not make them the same gear as the former owner believed.
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Offline lyndon

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Re: My "new" challenger
« Reply #10 on: November 14, 2007, 09:28:27 PM »
I was thinking motor mounts, too, because I think that's the only thing that makes sense in reverse only. Any clutch issue would  be a problem in forward gears, too, wouldn't it?. But I've only experienced the motor mount problem in smaller vehicles. Would a bus engine have enough torque to jump from a broken mount in a normal start? Maybe you could find a safe way to have someone watch the engine with the doors open while you try reverse. I would think it would be rather obvious, if that's what is going on.

Don
Don
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Offline Lin

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Re: My "new" challenger
« Reply #11 on: November 14, 2007, 11:06:09 PM »
I am not sure who I would get to stand in the back while it bucked into reverse.  Sounds like a new extreme sport to me.
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Offline lyndon

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Re: My "new" challenger
« Reply #12 on: November 15, 2007, 01:40:51 AM »
I am not sure who I would get to stand in the back while it bucked into reverse.  Sounds like a new extreme sport to me.

Well, maybe just off to the side a little.

If it's a motor mount, I would think that you could even hold the brake, slip the clutch a bit, and it would be fairly evident to the observer (when the engine tries to stand up on its side). Might be a bit of extreme sport for the engine, though.

Don
« Last Edit: November 15, 2007, 01:46:03 AM by lyndon »
Don
1988 MC-9

Offline Tenor

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Re: My "new" challenger
« Reply #13 on: November 15, 2007, 04:58:17 AM »
Can you put a video camera in the bay and film what happens when you go to reverse?  Some duct tape, bailing wire, bubble gum....  Saftey first!

Glenn
Glenn Williams
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1968 MCI 7 Ser. No. 7476 Unit No. 10056
8v71
4 speed Spicer

Offline Busted Knuckle

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Re: My "new" challenger
« Reply #14 on: November 15, 2007, 07:10:16 AM »
I am not sure who I would get to stand in the back while it bucked into reverse.  Sounds like a new extreme sport to me.

Lin bring it to our shop, we've done much worse! LOL! Some of the long time regulars may remember what I'm refering too! Back long before Dallas came to our place, we had a DINA that had a front end problem that NO ONE could find! And if you can't find it, you can't fix it! LOL! I won't get into detail as to how we found it, but rest assured with determination there are ways!
;D  BK  ;D
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KY Lakeside Travel's Busted Knuckle Garage
Huntingdon, TN 12 minutes N of I-40 @ exit 108
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;D Keep SMILING it makes people wonder what yer up to! ;D (at least thats what momma always told me! ;D)