ron and kristins starter comparisons..

[MDV Maria V]

Hello Here is the image of the old starter, teeth are the same, solonoid appears to be the same but pos and neg terminals are reversed from the other starter solonoid.  the teeth on the new starter and the teeth on the flywheel are a bit chewed up as they are not engaging (this is in response to a question posted on teresa's thread, earlier regarding the banging sound we were hearing when starting up new starter.  We were asked to start a new topic so will post our intro next!  Thanks for your help.  Background of our issues are to be found on Teresa's thread, we will repost them here! 

[luvrbus]

When did GM change to negative ground from the positive ground was it at the beginning of the 4106 or later in the run, weren't all 4104 GM positive ground ? thinking he may have bought a positive ground starter or maybe a 24 volt

good luck

[robertglines1]

Answer Cliffords point first! then ck to see if this starter gear is going into the flywheel further than the original starter.=the hard thump when enguaged

[TedsBUSted]

As far as I can think of, a starter motor wouldn't be polarity sensitive in any way that could affect engagement, could it? I believe that either solenoid terminal could be configured as "power" and "motor" without causing engagement issues.

A CW vs CCW rotation drive gear would have the opposite edge of the tooth beveled to lead during engagement, but the drive would also freewheel in the opposite direction.

Some motors require a spacer between the motor end and flywheel housing.
How 'bout a picture of the two starter's drive ends, side by side?

After confirming an exact match with the original motor, I would say that Ron and Kristin's next step would be to energize the installed starter's solenoid, without energizing the motor, to check the drive engagement.

Ted

[TedsBUSted]

Thanks for the welcome!  Ok, here is a mystery that we are hoping to solve...From Evernote:
Bus notes as of 5/03
Symptoms of exisiting bus issues: annendum as of 3 weeks ago
Start of  bus  was hard as if batteries were low.  Amp meter on dash showed heavy discharge, as in pegged the needle on discharge side of guage at low RPM.  
When motor was at high RPM, it was charging.  Turned off bus, could not restart.  Starter solonoid hit hard, would not turn over engine.  Separated house and coach systems and determined house system not of issue but never reconnected two systems.
Very slowly and systematically went through electrical system looking for dead short, with voltmeter.  Multiple minor issues found.  Put in new set of brand new 8D coach batteries,  still would not start coach.  Roll started, fired right up, ran well, voltage meter still full discharge. Turned off bus, would not restart. After turning off bus and trying to restart, solonid does not click or make any sound whatsoever.  Spent several days looking for and running down several issues:
1. ignition switch corroded and not turning off completely, minimal amount of power running through at all times
2. all switches on dash faulty, not performing properly or shutting off- corrosion
3.  went over electrical system, eliminated all wires that were not being used.  Re-sautered new ends on all wires in question.  Found one wire with total dead short.  When disconnected, rest of system appeared to not be shorting out
4.  Put new starter in , old starter was bad.  Wire with dead short disconnected..of unknown origin, location at service panel next to driver seat.
5. started bus, bus starts well, total discharge on meter, wire with dead short still disconnected-
with bus not running there was no discharage on batteries when wire with short was disconnected but total discharge when bus was started.

Next issue:
installed rebuilt starter originally in a 4106 w 8v71.  Starter sounds like someone is randomly beating on it with 4 lb sledge hammer when engaged, stops when disengaged.  Were there different starters for different busses? Without having counted the teeth, they appeared to be the same, rotation is correct...getting ready to tear apart again..aargh, so hoping for advise soon!

Sorry, I replied before I read the above from the "other" thread.
Now that I know it's an '06, with a practically inaccessible starter  motor, I'll retract my suggestion of engaging just the solenoid. Instead, careful measuring will have to be done on the bench.

So R&K, does the engine start now, but with a terrible "clanking" during crank?

[happycamperbrat]

Here are the 2 starters side by side for comparison

[TedsBUSted]

Glad to see that the original motor didn't get away, that's good.
Do not surrender it until the cranking problem is solved.

I'm almost positive that the "flag" connector and solenoid configuration aren't a concern here.
I'm betting on a mismatch at the drive end.
Could we see the drive ends pictured side by side?

---

[happycamperbrat]

If this isnt a good enough pic, I can retake

[TedsBUSted]

From here, the drive gears look different. The flanges also look to be slightly different and "clocked" differently. The mounting flanges are  just different enough that there could be mounting interference with some applications. But the big issue would be tooth count of the drives. Count the teeth, looks like a mismatch from here.

Instant and final starter failure is relatively rare. Since the engine seemed to have been cranking fine before the various electrical issue cropped up and drained the batteries, I'd be tempted to give the original motor a bench test with a known good battery.

Ted

[happycamperbrat]

Thanks Ted! I will tell them in the morning. I think they might be asleep now. But I think Ron said he had counted the teeth and they were the same.....

[TedsBUSted]

They may be the same, it's hard to tell for sure from the pictures, but in all likelihood some difference on that end of the starter is causing the problem.

good luck

[fe2_o3]

Could the solenoid be kicking out and reconnecting? I had an old chevy do that and it ate the ring gear...Cable

[happycamperbrat]

Well, if it is the wrong starter........ umm, any idea where they could get another for less then $500.00? That was what Napa had quoted him.....

[zubzub]

Buddy has so many electricity issues.....is he even sure the  original starter is toast?  Bench test it.  I have quasi rebuilt a starter on the side of the road, redressed the commuter end, , dressed the solenoid contact points, lubed moving bits etc....took maybe an hour tops...has worked great since then....since he has an extra starter there he can scavenge brushes...solenoids/whatever from one to the other.

[happycamperbrat]

I think youre on to something there zub!