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Author Topic: I'm a rookie/ won't start on COOL days  (Read 3607 times)
Stone
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67 MCI 5A Challenger 8V71 allison MT644




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« on: November 05, 2007, 06:50:59 AM »

Hello I am a newbie to your board...I have had a bus for 4 years now as well as getting bus conversions magazines for 4 years.. I just decided to join the board...I AM A BUS NUT...

I got a question '  I have a 67 MCI 5A with an 8v71 non turbo.  Is has an air throttle for starters.
When it is around 45 degrees outside like today here in PA the bus will not start.
It has been this way since the day I got it..I can move the throttle by hand at the rear and give it fuel and still won't start...I have to use the engine block heater to start it on COOL nights...I could see if it was 20 or 30 degrees but 45?  The bus runs perfect when running and when it is warm it starts as fast as I touch the start button.   Can anyone tell me if there is a problem with my engine or is this normal at 45 degrees?
thank you for responding...Ron
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bobofthenorth
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« Reply #1 on: November 05, 2007, 07:06:00 AM »

I'd say that's pretty normal for a 2-stroke Detroit.  Better batteries might help but it sounds like the block heater is doing the trick.
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R.J.(Bob) Evans
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« Reply #2 on: November 05, 2007, 07:19:02 AM »

I have a 67 5A also and was having the same problem at about the same temp.  That is until I learned the simple technique of the bump and wait start (for want of a better name).  In weather below 45 hit the starter for 8 to 10 seconds then wait for 20 to 30 seconds before you try another 8 to 10 seconds.  This gives the warmed compressed air time to heat up the cylinder a little so the diesel will do the big bang thing.  This method has worked for me down to about 35 degrees but I still prefer using the block heater if I have the time.

Ed
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TomC
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« Reply #3 on: November 05, 2007, 07:43:19 AM »

If the engine is in good shape mechanically and in proper tune (it can sound alright but be out of timing for cold start) it should start unaided down to the 30's.  Meaning- your engine is worn so compression is lacking to the point that makes it hard to start below 45 degrees.  The only real solution is to have the engine overhauled (overhauled=replacing worn out items; rebuilt= replacing all internals with new).  Also, as stated, a good precision tune up can do wonders.  Make sure you have winterized your fuel with water suspending stabilizer.  Good Luck, TomC
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Tom & Donna Christman. '77 AMGeneral 10240B; 8V-71TATAIC V730.
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« Reply #4 on: November 05, 2007, 07:49:11 AM »

I read on the board that most just use 2 group 31 batteries and on a 24v system thats not enough when its cool.a 8v71 should start easy at 45 degrees one other problem we ran across on the 8v71 was the re builders even DD use turbo pistons on NA engines lowering the commpression making for harder starts
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Stan
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« Reply #5 on: November 05, 2007, 07:59:04 AM »

The biggest deterrent to cold weather starting is cranking speed. You are fighting thick oil and reduced battery capacity. Good batteries and a good starter are required. With a slow moving piston, too much heat is lost to the cold cylinder walls before the piston get to the top.
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DavidInWilmNC
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« Reply #6 on: November 05, 2007, 08:54:24 AM »

I don't have much to add, but my MC-8, also with an 8V-71, will start with no block heater down to the upper 30's - the coldest I've tried it.  It'll start easily in these temps even after sitting for 2 months without running.  This particular engine has around 30,000 miles on it since being rebuilt.  I now use 2 Group 31 batteries (all connections are clean and tight).  I haven't started it in these temps with the 31's, though; I switched from the 8D's back in the spring.  I do have a solenoid that'll jump between the house and starting batteries if it's an issue.  My 8D's are only 2 years old and kept charged (as are my 31's now).  What size / age / condition (kept charged) are your start batteries?

David
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Tom Y
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« Reply #7 on: November 05, 2007, 09:31:53 AM »

Ron, I can't add to the comments but was intrested in what part of Pa you reside?  Tom Y
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Tom Yaegle
Stone
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67 MCI 5A Challenger 8V71 allison MT644




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« Reply #8 on: November 05, 2007, 10:35:42 AM »

Ron, I can't add to the comments but was intrested in what part of Pa you reside?  Tom Y
Tom I am in Washington Pa . I see you are in Warren . I sure would like to stop over some time and see your bus ..As well as make some bus nut friends...At this time I do not have any friends that are into buses.... Grin
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Stone
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67 MCI 5A Challenger 8V71 allison MT644




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« Reply #9 on: November 05, 2007, 10:41:06 AM »

I don't have much to add, but my MC-8, also with an 8V-71, will start with no block heater down to the upper 30's - the coldest I've tried it.  It'll start easily in these temps even after sitting for 2 months without running.  This particular engine has around 30,000 miles on it since being rebuilt.  I now use 2 Group 31 batteries (all connections are clean and tight).  I haven't started it in these temps with the 31's, though; I switched from the 8D's back in the spring.  I do have a solenoid that'll jump between the house and starting batteries if it's an issue.  My 8D's are only 2 years old and kept charged (as are my 31's now).  What size / age / condition (kept charged) are your start batteries?

David
  Hello David my batteries are 8D and the were new this July. I am new to replying to these messages so I hope I am doing ok........ Undecided  thanks to all that replied......Ron  (nick name STONE )
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zimtok
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« Reply #10 on: November 05, 2007, 03:00:08 PM »

With my 6-71 anything below 55deg I turn on the block heater for at least an hour if not 2 hours before trying to start it.

Your batteries will thank you....
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1960 PD4104-4971 - Memphis TN

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« Reply #11 on: November 05, 2007, 03:09:20 PM »

There is one other factor that comes into play when you use the crank and wait (is that anything like crank and pray??) method. You warm the batteries when you load them during the first try.  Then when you crank the second time, they are able to produce a little more voltage during the second try.  Sometimes, during severely cold weather, warming a battery by leaving the headlights, loading the battery for a couple of minutes prior to starting, will make a  difference. FWIW
Dennis   
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Blue Ridge Mountains of VA   Hi Yo Silver! MC9
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« Reply #12 on: November 05, 2007, 03:14:02 PM »

Have NOT read the prior posts, soossss if I duplicate....ops.  Try this old trick learned from the mists of time and space.  If your MCI has a manual pull-to-stop cable, leave it out in the "off" position, then crank the mill for about 10 seconds.  Then push in the cable to the "run" position and crank normally to start.

This technique lets the cylinders heat up from the mighty compression ratio of your mighty Detroit.  Might do the trick.  If not the first time, try it up to 3 times, then let the starter cool for about 3 minutes.  You mill may start with this trick employeed.  Then again it may not.  Block heaters for suress.  Smiley Smiley Smiley
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Stone
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67 MCI 5A Challenger 8V71 allison MT644




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« Reply #13 on: November 05, 2007, 04:34:14 PM »

Have NOT read the prior posts, soossss if I duplicate....ops.  Try this old trick learned from the mists of time and space.  If your MCI has a manual pull-to-stop cable, leave it out in the "off" position, then crank the mill for about 10 seconds.  Then push in the cable to the "run" position and crank normally to start.

This technique lets the cylinders heat up from the mighty compression ratio of your mighty Detroit.  Might do the trick.  If not the first time, try it up to 3 times, then let the starter cool for about 3 minutes.  You mill may start with this trick employeed.  Then again it may not.  Block heaters for suress.  Smiley Smiley Smiley
  I did ask' and you did respond but I got this thing about not cranking the starter more than 2 or 4 seconds at a time   so I end up using the block heater....I just thought there may be an easy fix or a trick you folks know that I did not....thanks again....It is nice to make some bus nut friends.....
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mikelutestanski
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« Reply #14 on: November 05, 2007, 05:07:40 PM »

Hello:    Mike from Dunnellon fl..  72 mci 7     Have a relative in Washington Pa  .. south of Pittsburg.. (same town ??)  hope to be up there next spring. Will get in touch  if it is all right with you..  FWIW  always used the block heater for 2 hours when back in upstate NY.  never failed  45 or below .     Happy Bussin    mike   
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Mike Lutestanski   Dunnellon Florida
  1972 MCI 7
  L10 Cummins  B400R  4.625R
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