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Author Topic: MC-9 / 8V71 Woes  (Read 30204 times)

Offline BlueScarecrow

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MC-9 / 8V71 Woes
« on: December 27, 2009, 01:50:38 PM »
Recently purchased an MCI MC-9 Crusader II on eBay. I'm finding that it is going to need a lot of attention, but I've fallen madly in love with my MC-9 and I'm willing to go the extra mile.

One issue is the Detroit Diesel 8V71. It blows both white smoke on start-up and also black smoke. The other day after I started it up and ran it for a couple of minutes and it "Ran Away" for about 3 seconds. That scared the heck out of me. I don't want to lose my MC-9 with the engine going ballistic.

Haven't heard a lot of positive things about the 8V71 other than it is a very powerful engine; I already know that. It uses a ton of oil and I want to get away from that problem too.

I've talked to many truck drivers and they are all talking about the Cat C-13.

Anyone have any ideas? :-\

Thanks!


Mike
N9EWS
« Last Edit: December 27, 2009, 02:01:18 PM by BlueScarecrow »
1983 MCI / TMC MC-9 Crusader II - DD 8V71  Located in Scottsdale, AZ  85252

Do you think that's air you're breathing? - "The Matrix"

Offline Kwajdiver

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Re: MC-9 / 8V71 woes
« Reply #1 on: December 27, 2009, 01:55:41 PM »
Mike,

Welcome to the board,,, I see this is your first post.  I also have a MCI-9 and love it.  I'm not your engine expert, but a lot of guys here on the board will be glad to help.  It will take a while to get all the bugs out of your bus.  Hang in there.... and knock them down one at a time.

I'm sure help is forth coming.

Post some photos of you bus.

Bill
Auburndale, Florida
MCI-9
V-6-92 Detroit, Allison 5 spd auto
Kwajalein Atoll, RMI

Offline WVA_NATIVE

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Re: MC-9 / 8V71 woes
« Reply #2 on: December 27, 2009, 01:57:50 PM »
BK loves them CAT'S you cans ask him and also Tom C. is my first choice for anything engine related.

WVaNative

Online luvrbus

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Re: MC-9 / 8V71 woes
« Reply #3 on: December 27, 2009, 02:01:38 PM »
Mike your 8v71 ran away because of fuel and oil build up from long periods of idling run that baby and don't idle for long peroids may 1 or 2 mintues at most then check the air cleaner if you still have a lot of black smoke have somebody run the rack and set the injector timing and check the injectors one may have blown a tip  and fix your leaks, it blowng black smoke it is not burning oil.
A question for you how much oil is dripping from the air box drains from each side and do you know what oil the PO has in the engine they will smoke,leak more and use more oil with 15/40 oil
The 8v71 will be around when the C-13's are long gone the enjoy your trip.  

good luck
« Last Edit: December 28, 2009, 04:33:32 AM by luvrbus »
Life is short drink the good wine first

Offline James77MCI8

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Re: MC-9 / 8V71 woes
« Reply #4 on: December 27, 2009, 02:03:26 PM »
I have an 8V71 in my 8 and have no problems with it. The white smoke on start up is normal for a two stroke DD. The black smoke could be caused by a clogged intake filter , incorrect timing or any number of other things. The run away that you described could be caused by the rack hanging. Find you a good two stroke DD mechanic and have the rack run. Others here will be helpful with a diagnosis also.  

Things I have learned here about the two stroke:

1. Do not idle the engine for long periods
2. If you are going to start it. at least take it for a run so that the engine will reach operating temp.
3. Allow the engine to seek its own oil level. Overfilling will result in oil being blown out.
4. Keep the air filters clean.
5. Keep the fuel filters clean.
6 It is a DD drive it like you are mad at it.
77 MCI 8
8V-71 4 spd

Offline Depewtee

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Re: MC-9 / 8V71 Woes
« Reply #5 on: December 27, 2009, 02:21:47 PM »
Mike,

Welcome to the board and nice garage!  The bus ain't bad either.  I am fairly new to the board also and have learned a lot from reading what these wise ones have to say.  My bus is an '84 MC9 with a 6V92T.  It has taken some time to get used to the DD, but now I think it is a wise choice for our buses.

Brian S.
Brian Shonk
Fort Walton Beach, FL (Florida Panhandle)
1981 Prevost LeMirage Liberty Coach
1984 TMC MC-9

Offline BlueScarecrow

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Re: MC-9 / 8V71 Woes
« Reply #6 on: December 27, 2009, 02:24:05 PM »
Thanks gang for all your wonderful replies.

When I'm on the Interstate and I get it in 5th gear... the motor flattens out and gets real quiet. I look down at the speedometer and it's at 78 mph. Yow!

I am looking for a mechanic here in Phoenix. And I'd like to be present during the rebuild as I have no experience with diesels, but I would love to learn. I'm a very quick study.

Read a post once where a fella said that if you have an DD 8V71, put your hand in the jamb and slam the door. That will put you in the right frame of mind for driving it. LOL :D

Thanks!


Mike
N9EWS
1983 MCI / TMC MC-9 Crusader II - DD 8V71  Located in Scottsdale, AZ  85252

Do you think that's air you're breathing? - "The Matrix"

Offline James77MCI8

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Re: MC-9 / 8V71 Woes
« Reply #7 on: December 27, 2009, 02:25:14 PM »
Nice Bus and garage!
77 MCI 8
8V-71 4 spd

Offline James77MCI8

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Re: MC-9 / 8V71 Woes
« Reply #8 on: December 27, 2009, 02:26:35 PM »
A DD purrs much better than a Cat!
77 MCI 8
8V-71 4 spd

Online luvrbus

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Re: MC-9 / 8V71 Woes
« Reply #9 on: December 27, 2009, 02:36:41 PM »
If you can attend the rally in Quartzsite Jan 21-23 Don Fairchild will be there and tell you what you need before taking to somebody like WW Williams.
If you need a 2 stroke mechanic Berry Machinery in Chandler has a couple of good ones if they have time to work on the bus.
Here in Mohave Valley Az where I live A&A Diesel is a good shop at fair prices I know Andy is good he thinks the 2 strokes were the best ever built.



good luck
« Last Edit: December 27, 2009, 02:56:20 PM by luvrbus »
Life is short drink the good wine first

Offline Dreamscape

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Re: MC-9 / 8V71 Woes
« Reply #10 on: December 27, 2009, 02:44:47 PM »
Nice coach!

You will like the 8v71 once you get it out and drive the heck out of it, that's what they like. They've been around a long time and will be for many years to come. We have one also in our Eagle, it lacks power when climbing long grades but that's the only downfall. It's plenty fast on the straights as you found out. Our blows white and blue until she warms up then it's good to go, black if I have my foot into it. The cost of a re-power is way out of my league, but a rebuild isn't cheap either. Run what you got, have the rack run and check the injectors as others have mentioned. You can burn a lot of fuel for many years for the cost of a rebuild.

I'm assuming since you've had it a short while you don't have many miles behind the wheel. Take it out for a spin and get used to her, she will reward you with years of service. Just use the correct oil, get some manuals, find a good DD mechanic and you'll be happy. Sure you can hot rod it if you have the money, Don's the man for that.

Have Fun,

Paul
Becky and Paul Lawry, On The Road
Travel Blog - http://dreamscapetravels.wordpress.com/
Bus Blog - http://dreamscapesilvereagle.wordpress.com/
______________________________________________________

Our coach was originally owned by the Dixie Echoes.

Offline buswarrior

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Re: MC-9 / 8V71 Woes
« Reply #11 on: December 27, 2009, 03:56:53 PM »
You are a sitting duck to be taken advantage of.

If you get told you need a rebuild, and you will, how are you going to know it's the truth?

And what constitutes a rebuild, in the mind of the guy about to screw you?

As part of your diagnosis, the above mentioned "tune up" procedures will help a reputable shop determine the health of your engine along the way.

You need the advice of a reputable shop, and driving the coach 1000 miles to get to that shop is money and time well spent for a busnut. We have no way of recouping the costs of shoddy workmanship like a commercial operator does.

So, busnuts, where should he take this coach for some TLC?

happy coaching!
buswarrior
Frozen North, Greater Toronto Area

cody

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Re: MC-9 / 8V71 Woes
« Reply #12 on: December 27, 2009, 04:04:25 PM »
My thoughts are to hit Q and let don check it over, if needed there will be a line of very qualified BUS mechanics ready and willing to stand right beside don and you will get an honest apprasial on the condition, I see it's a church bus, did they tell you how many miles on the rebuild?

Online luvrbus

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Re: MC-9 / 8V71 Woes
« Reply #13 on: December 27, 2009, 04:17:22 PM »
If he wants the bus serviced and a check over take it to Michelangleo of Phoenix they own MCI's and are great people but I don't think they do engine work but there they will let him watch and explain the different systems.
Andy or Bill do you have the phone # I can not find it in the search here.
Mike a word of advice don't take your bus to Desert West or Taylor in Phoenix been there done that.   


good luck
Life is short drink the good wine first

Offline Busted Knuckle

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Re: MC-9 / 8V71 Woes
« Reply #14 on: December 27, 2009, 04:51:12 PM »
If he wants the bus serviced and a check over take it to Michelangleo of Phoenix they own MCI's and are great people but I don't think they do engine work but there they will let him watch and explain the different systems.
Andy or Bill do you have the phone # I can not find it in the search here.
Mike a word of advice don't take your bus to Desert West or Taylor in Phoenix been there done that.   


good luck

Clifford,
Funny you should mention Desert West  >:(

They were the lien holder on the first bus we ever owned ('90 Setra S215 HDH) and had it repossessed prior to us buying it. Between them and their agent one of them tried to screw us out of the $15,000 we'd paid and thought they could dup us into paying double in order to receive a clear title. A phone call to the AZ & MO (where thier agent was from) States Attorneys Offices brought a clear title screeching to our door unannounced by FedEx straight from Phoenix less than 48 hrs after the call was made.

I've said it once, and I'll say it again. When it comes to who knows who in the bus world Clifford knows the goods on all of 'em good and bad! (never seen him make a bad call yet!)

So Mike take Clifford's advice and trust your bus with it, and trust me you'll never go wrong listening to Clifford! 

Welcome and enjoy yer bus! And HAPPY NEW YEAR! (now take that bus for a spin and go to Quartzsite and meet up with some of the best busnuts you'll ever meet and you'll have plenty that will give you a hands on education right then & there!) FWIW
;D  BK  ;D
Busted Knuckle aka Bryce Gaston
KY Lakeside Travel's Busted Knuckle Garage
Huntingdon, TN 12 minutes N of I-40 @ exit 108
www.kylakesidetravel.net

;D Keep SMILING it makes people wonder what yer up to! ;D (at least thats what momma always told me! ;D)