starter question

[fortyniner]

Will those sexy gear driven starters work in the vdrive buses like a 4106? With the "cooler" weather the 12v direct drive starter in the 4106 aint cuttin it. The 4905 with 24v starter spins like a top and fires up fine even in cold weather.

-Tom P.

[buswarrior]

Age/condition of your battery cables?

The creeping green and black plague adds up over the years.

I saw 6 year young battery cables on a big fleet Prevost powdered right through under the factory heat shrink.

No fun changing a starter and get the same performance afterward?

happy coaching!
buswarrior

[fortyniner]

Cables including ground are new with fresh clean ends. Batteries are not quite two years old. New master switch also.  Starter had some work done on it according to receipts. Cables get hot when cranking and it cranks slow. Starter is real hot too. I was just going to convert to 24v but a modern starter would save a lot of effort if one is available. The only ones I found are all cw rotation but I was thinking we needed ccw rotation.

[gus]

Hot cables and starter almost certainly mean high resistance in the system or low batteries. My guess is low batteries. Age has nothing to do with it, condition is the key.

Maybe your new cables are too small, the originals are huge.

The stock starter properly wired will do the job easily.

[bobofthenorth]

The answer to the OP's question is that the gear drive starters are physically much smaller than the old style starters they replace so they will fit wherever the older starters fit.  Personally I'm a big fan of the gear drive starters even if you don't NEED the higher torque.  The gear drive starter is much lighter and therefore easy to change but my experience has been that I don't need to change it.  I was changing my 42MT more often than I was changing oil.

However as others have identified, a gear reduction starter is not a replacement for adequate cables and batteries.

[dickegler]

Hi Tom,

I don't know anything about the gear drive starters, but my first Eagle was always slow to roll over and start.  I finally determined the PO had  apparently installed a 24 volt starter in a 12 volt system.  You could not wipe the grin from my face when I installed a 12 volt starter and she whipped over and started right up.

There were so many things done backwards on that conversion that it was not much of a surprise that they had screwed the starter up too.  I learned never to assume anything previously done was correct

maybe that'll help

keep on bussn

dick egler

[fortyniner]

These are good ideas. The cables are the same size as the old ones so maybe the batteries are failing. I guess swapping them out with the ones in the 4905 is worth a shot. Id still like to know
if the new gear drive starter will fit the left hand rotation motors since theres a chance its not up to snuff.

Bob, is your bus engine right hand or left hand rotation? I believe all the old GMs were left hand rotation so the starter would have to spin ccw.

-Tom P.

[bobofthenorth]

I always forget that some of these engines turn the wrong way.  The Delco site says CW only.  There is a Mitsubishi equivalent - maybe they do CCW but its probably not that likely.  I don't suppose there's a whole lot of call for CCW starters any more.

[Lin]

I had a start problem recently.  It hesitated a bit before turning, but then would start up.  I went through everything before attacking the starter itself.  It got so hot that one of the battery terminals melted.  That convinced me that there was a massive draw from the starter itself.  We had it rebuilt and it sings.

[RJ]

Tom P -

Yes, you need a CCW starter for the V-drive, unless you've got an S-50 powerpack in it.

Pulling the starter is a PITA on the 6V & 8V engines - using the access hatch from inside is a good thing.

A long extension may help get the one hated nut loose, so you don't have to remove the exhaust manifold.

Any competent electric motor shop should be able to rebuild the unit for you, they're quite simple, actually.  Just make sure the bendix drive is in good shape.  Oh, and don't forget to tell them it's a CCW unit!

But before you go thru all this, double check the batteries, or swap over the ones out of your other bus, to see if that improves things.  One bad cell that's drawing the rest down, but only under load, might be the cause.  Besides the voltage, check the specific gravity, too. 

It also could be, if you've got to turn the engine over a lot before it starts, that it's tired and not the starter??  I've seen 8V71s fire off in less than one crankshaft rotation, and others that you've got to nurse along several times to get them running.  Temp affects them, too - it's been cold.  Got a block heater?

No need to convert to 24v for this, a good 12V starter will spin the Detroit nicely - with adequate batteries providing the "umph."

FWIW & HTH. . .

[06 Bill]

Fortyniner   The starter in my 06 took to spinning real slow no matter what I did. Bottom line was there is a small
jumper strap on comm. end brush holder that had burned through. Fabbed a new and heavier one and all is fine.
                           06 Bill    4106 2147

[fortyniner]

Digging through old receipts I see several for starter repair including one that says starter had wrong fields installed! I have a bad feeling about the starter but Ill get a battery hydrometer and check cells this weekend.
Ill update this thread when I eventually get it figured out.

-Tom P.

[jjrbus]

My Hero Jerry Jenkinson aka Sojourner posted this step by step diagnosis, maybe it will help? Worked for me.

ice of you to help. Spinning Jim may still need you or who ever is closer for extra hands to do this and repair.

If I were there to witness & diagnose your problem, I can find your problem. For not being there I will try to give you step by step and hope I didn't miss any. Let us know what you're finding. Am not surprise it something else that not been reported.

Here are few steps to diagnoses starter & solenoid & bendix & relay before solenoid & NC (normal close) fuel pressure switch problem: Please use an analog meter only...so you can watch needle to be steady or erratically like a loose connection or dirty relay's points for diagnostic reason. Alligator clip on both test leads to get a good sable connection. Set meter range at 30 volt DC or the next higher scale.

Before the tests, the batteries should be at 80% or higher state of charge for diagnostic checks but not cranking voltage test unless full state of charge.

I attached a wiring circuit with numbers which label each test points.

A) NC fuel pressure switch:
1) Hook + test lead to #7 and – test lead to #8...while cranking, it should read 0 voltage until it starts.. If it erratically or full battery voltage before engine run...bad pressure switch. Hook up + test lead to #8 and – test lead to chassis GRD... it should read 0 voltage until it starts. If it erratically or full battery voltage before engine run...poor ground wire or connection.
2) If fuel pressure is higher then 8 psi @ cranking speed...checks for restricted return fuel line flow. It will cause the starter to shut down automatically.

B) Starter switch relay before solenoid:
1) Hook up analog meter + test lead to #6 and – test lead to chassis ground...it should be at battery voltage while cranking. Otherwise if it erratically meter movement....bad starter button switch or wire connection.
2) Hookup analog meter to solenoid coil post (#5) (it the same + from battery post) with + lead and – lead to (#4) pressure switch. Watch voltage meter for steady cranking voltage reading while hold down the start switch...if it 0 voltage while cranking is good. If it does erratically while using either front or rear starter switch mean bad wire connection to or in the relay or bad relay points.

C) Solenoid:
Hookup analog volt meter with + test lead to + post (#1) of solenoid and – test lead to starter's + post (#2). Watch for meter goes to 0 voltage while cranking...that is good. But if it erratically...bad connection either in solenoid's contact switch or starter's brushes or wire connection. Take it to repair shop for further testing or replace both solenoid & starter motor with warranties.

D) Bendix Drive:
1) Wrinnninnnn noise (spinning) mean over run clutch is slipping, mean a bad bendix drive.
2) Very loud gear clashing before fully engage...either worn gear's teeth    or    starter is spinning before fully engage...solenoid connecting link is out of adjustment or worn out. Replace both solenoid & starter motor with warranties.

E) Starter Motor:
Hookup analog or digital volt meter to solenoid's + post (#1) and the – lead to engine's ground. Watch for voltage dropping at the beginning & during cranking.  If the voltage is below 18v with a fully charged 24v system and growling noise mean starter bearing is worn out to cause armature to rub on field poles. Replace both solenoid & starter motor with warranties. If no growling noise...check power source for weak & "hot" (high resistance) connection of both the + positive & - negative. While cranking with fuel shut off, it should never have more then .5 volt drop between #1 and starting battery's + post. Same way with grounding between engine to battery – post of no more then .5 drop. Under size wire or cable will cause greater voltage drop as well old cable with a few broken strands from too much vibrating and/or corroding.


Whatever you do about getting parts replacement, always take the old one with you to the store same or newer version.

FWIW

Sojourn for Christ, Jerry

http://www.busconversions.com/bbs/index.php?action=dlattach;topic=9118.0;attach=9325

Original post    http://www.busconversions.com/bbs/index.php?topic=9118.msg90500#msg90500

Hope this helps   JIm

[fortyniner]

Ok, I think Im in trouble now.Can the starter be unbolted working from the access panel? I Pulled bus onto driveway to clean the concrete pad. When I went to move it back it refused to crank then solenoid didnt even engage. Rapped on started and it briefly engaged then nothing.

So bus is stuck in the dirt driveway and wont start so I cant get under it and Im having the dickens getting to the bottom starter bolt. Ive pulled the exhaust manifold but cant get socket and extension on the bottom bolt. Feels like some bump on the block is in the way.

Anyone know if it can be unbolted from the access panel?

-Tom P.

[buswarrior]

put the easy ones back in, so the weight of the starter isn't binding the hard one.

happy coaching!
buswarrior