starter motor binds

[why]

1965 3000, for many years now, if car is driven and then sits so temp about 130deg or higher, when I turn key I get the attempt to start whir from starting motor as if weak battery, sometimes just the jiggle of pushing clutch in and out, or always with the more aggressive taps on front of start motor with wheel nut hammer it turns over and starts just fine. new brushes etc. Decided maybe it was binding and I did not center it right last time I had it apart or that it needs lots of grease on end of shaft bushing so just took it out to redo the two long thin bolts to make it sure they are tightened evenly and to put grease in that end cup, and I noticed: The copper colored part that the brushes go up against, for about 15% of its circumference is clearly not round, but has a little up down flatish spot on it, barely discernible visually, but noticeably if run finger around circumferenc. Could that be my problem? What would cause it? Anything to do other than replacing starter or just carry on with occassional hammer taps if car not left long enough to cool.
Thanks, Jay Glass

 

[Michael Oritt]

Remember how often we would see Dave Russell's quick and responsive posts to questions such as this, often with illustrations and pictures.

Dave, if you are reading this: We miss you and wish you well.

 

[Randy Forbes]

Gear-reduction starters work miracles on Healeys.

I've now put them on one (1) MGBGT and my Healey. They start the car so fast, it scares you.

Beats getting the hammer out...

 

[Bob_Spidell]

If your starter motor spins rapidly but doesn't engage the flywheel it's probably a problem in the Bendix gear. I've also heard about, but not experienced, a problem with hot starters due to a heat-soaked field coil (but that causes the motor to not turn). The "copper colored part that the brushes go up against" is called the commutator, and should be round but I don't think that's your problem. I also think the "when hot" issue is a coincidence; I think it's the Bendix gear else tapping the motor or pushing in the clutch would have no effect (also wouldn't affect a flat-spotted commutator).

On the bench, check the Bendix spiral/worm gear mechanism for smooth operation. There's also a light spring behind the bendix pinion gear that often breaks. While you've got the unit apart, have an electric motor shop turn the commutator, and make sure the insulation between the lobes of the commutator is slightly below the lobes (you can cut them down with a hacksaw blade).

 

[BOBBYR]

Hi Jay,
I had the same problem about 4 months ago. Anyway ,the problem turned out to be the bendix was getting stuck in place on the starter shaft.After removing it from the engine, I cleaned the bendix with carburator cleaner. The bendix on my starter was loaded with old oil and grease and dust from the clutch assembly. After cleaning it and working the mechanism by hand with some light oil, I got it freed up pretty good.Before putting it back in the car I cleaned off the excess oil with compressed air. I haven't had a problem since.I hope this is a help to you.
Good Luck,
Bobby R

 

[why]

Bob: thanks for the description but the starting motor does not spin, that is the problem, you get just the very brief little sound of it trying to turn the engine as if the battery is very low. For about 6 years the only time it happens is during that heat range. I did not mean holding the clutch down, simply a sharp push to the floor and then quick foot off release will sometimes solve the problem. After a few taps with hammer it functions as it does when cold, just fine. Jay Glass, Laguna Beach, '65 3000

 

[BOBBYR]

Hey Jay,
As you can tell, I didn't realize what problem you were having with this starter.I guess you only have two options. I do like the gear reduction starter. In my case, I'm into keeping everything stock or original.You might want to contact Moss or British car specialists for some parts to rebuild that starter.I'd be interested in hearing from you, when you figure out what the problem is. Thanks for your response and good luck.
Bobby R

 

[Bob_Spidell]

Two guesses: the out-of-round commutator or broken-down insulation on the field coil windings.

 

[why]

thanks to the Bobs for the comments, the fundamental fact is that when cold, very hot or just warm, the starting motor worked fine,it is hard to imagine a signficant flaw that would match this set of facts. Over about a six year or more period,time after time when in that magic 120-180 deg zone,tapping specifically on the end of the case at the front would make it start. I took it apart and it was very neat and tidy since I have been doing this about once a years for the past many years as I would have a new idea of what was wrong. All electrical checks were fine, new brushes,etc. etc.(car 47,000 orig miles, I put about 750/year on it with weekly drives) This time I simply packed the cap on the end with grease and put it all back together, doing my best to tighten the two screws that hold it all together evenly. One shot result: it now spins on start from cold faster than I can recall, we had a cool day so over an hour lunch it went down to 120 and fired right up. Oh by the way, I learned the cap can be pulled off in situ, no need to take it out of car, weighs a ton, lower nut a nightmare, and then take it all apart to put in grease.

 

[Rob Glasgow]

I had a similar problem with my BT7. Starter would spin freely 95% of the time. However, SOMETIMES, if the engine was very hot, it would either only click or turn a partial revolution. If I repeatedly pushed the starter button or the car cooled off, it would spin.
Turned out to be the battery cable connections. Cleaned both the battery and starter ends and the cut-off switch connections. Hasn’t had the problem again in 5 years. Also, make sure your battery is up to it.

 

[Michael Oritt]

Also check the ring gear--it may be cocked slightly on the flywheel.

About a year after buying my wife's 3000 we began to have a problem with starting, but was always able to eventually get past what seemed like a point of bind.

After having the starter rebuilt, then installing a new solenoid and eventually a gear reduction starter without solving the problem I examined the ring gear through the starter hole and saw that it had split and moved slightly on the flywheel.

A tack weld worked for a while but eventually I had to pull out the transmission and fit a new ring gear.

 

[why]

Rob, many thanks, sounds exactly like my problem--the dreaded "oh, they all do that"-- a high resistance somewhere was my operating principle for first several shots at fix, but never went further downstream than connection at starter, will trace backwards to battery and cut-off switch--maybe tapping battery posts and cutoff switch would at least save me from moving hammer from boot to engine compartment.

 

[why]

Rob: Thanks, the battery and shut-off switch had been cleaned recently, I cleaned the terminals on the solenoid and now have 5 starts at hostile temp range and worked every time. Expect a bit of a bind in starter (thus hammer tap helping) put demands on current flow through high resistance at one of the solenoid terminals, heat probably exacerbated one or both of willingness to bind and terminal problems, boy, can feel the lowered anxiety when I take it out.