<VV> Re: dog words

[djtcz at comcast.net]

> snip < 
> a set of dog clutches  (rollers) ....................

I think rollers are the sign of a sprag clutch.

I think a dog clutch has steel blocks or teeth that engage with pockets or another set of teeth.  Like how transmission gears are engaged/disngaged when shifted

--
Dan Timberlake

-------------- Original message -------------- 
>> 
> > Hokay folks, things are getting a bit confused here. 
> > A GM starter is made 
> > up of two major components (and has not changed a 
> > whole lot since 1914), 
> > the starter motor and the solenoid. 
> > 
> > When the solenoid fails, nothing happens (or maybe a 
> > click). Major failure 
> > mode after 40 years is a burned contact plate. The 
> > motor again has two 
> > major elements, the motor itself (armature, field 
> > coils, brushes, 
> > bearings). A rebuild usually consists of bearings 
> > and brushes though 
> > occasionally you will find a [shorted|open] armature 
> > or burned contacts on 
> > the armature. The other element in the motor 
> > assembly is the bendix drive 
> > in the "drive end". This unit slides on a splined 
> > end of the armature. 
> > 
> > On starting the solenoid pulls a stirrup assembly 
> > which moves the drive 
> > from the disengaged position into contact with the 
> > ring gear on the 
> > flywheel. Once fully pulled out and the gear is 
> > engaged, a contact is made 
> > in the bottom of the solenoid that energises the 
> > motor. As long as the 
> > motor is trying to spin faster than the engine, a 
> > set of dog clutches 
> > (rollers) connect the motor to the flywheel. and the 
> > starter spins the motor. 
> > 
> > To avoid spinning the starter at a speed greater 
> > than reasonable for an 
> > unbalanced assembly with smal plain bearings, when 
> > the motor stars, the dog 
> > clutches disengage, and the starter is not longer 
> > directly connected to the 
> > flywheel. 
> > 
> > When the rollers get worn, they no longer engage 
> > properly and may only turn 
> > the engine for a second or two before slipping. This 
> > is when you hear the 
> > starter speed up without turning the engine. This is 
> > more likely to happen 
> > when the bendix is hot and it heats up quickly in 
> > use. 
> > 
> > In general, the bendix drive is available as a 
> > separate part however the 
> > difficulty of removing a starter means that 
> > typically a general overall 
> > inspection will be made and brushes, bearings, and 
> > solenoid will be 
> > replaced along with the drive since the starter has 
> > to be disassembled (at 
> > least the nose piece removed) to replace the drive. 
> > 
> > More than you wanted to know ? 
> > 
> > Padgett 
> > 
>