STARTER MOTOR SPINS BUT DOESN'T ENGAGE

[RobH]

41 minutes ago, Rob Salisbury said:

the pinion is brought into play/mesh with the ring gear before the starter spins

I believe that is how all the 'high torque' starters are supposed to work too - on both four pot and six pot engines.  The internal contact doesn't 'make' to power the motor until the pinion has moved sufficiently far to ensure it should already be in mesh. 

 

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Edited December 12, 2022 by RobH

[John McCormack]

Having started this post 4 years ago I can now report I ended up fitting a hi torque starter. Problem solved.

I believe it was dirty contacts in the OE starter so the pinion wouldn't properly engage with the ring gear.

The ring gear teeth were worn down by about one-fourth of their full width, three-fourths still there. The hi torque starter works fine so it will stay that way until the box comes out when I'll turn the ring gear a 1/4 turn to have fresh teeth at the right spots.

[ntc]

On 12/12/2022 at 10:03 PM, BlueTR3A-5EKT said:

Am I dreaming this…?

the ring gear of a 6 pot can be pushed off the flywheel and thus away from the starter,  by the action of the starter bendix gear teeth not aligning every time with the flywheel teeth.   
 

Please advise  if this is wrong.
 

  On the 4 pot engine later flywheel the ring gear is bolted to the flywheel to stop this action.

 

Alternatively the crank thrust washers are about to drop out and the crank and flywheel are all moving away from the starter.

You wrong with the four stroke cycle the flywheel will always stop at three points.

[BlueTR3A-5EKT]

16 minutes ago, ntc said:

You wrong with the four stroke cycle the flywheel will always stop at three points.

Yep agree with that.

[astontr6]

On 9/27/2018 at 4:27 PM, John McCormack said:

Occasionally, maybe 1 in 5 times, when turning the key my starter motor will spin making a horrid noise and not engage the flywheel.

Sometimes it works next try, sometimes it takes a few tries. It has always started but one day it won't.

I have been travelling for 2 1/2 months with the car unused so I expect when I get home it will play up.

Removing the starter from a RHD PI is a job of work so I want to know the solution, if possible, before I do.

Solenoid, starter or ???

 

I would check the earth wire from the battery very carefully for condition and earthing points as that can play tricks like you describe. The S/ motor its self needs to be well earthed against the engine back plate, no rust or paint?

Bruce.

[RogerH]

On 12/14/2022 at 8:22 PM, ntc said:

You wrong with the four stroke cycle the flywheel will always stop at three points.

yes- on a 6 pot engine.

On a four pot - in twp places.

Not really to do with Four stroke cycle.

Roger

[ntc]

1 hour ago, RogerH said:

yes- on a 6 pot engine.

On a four pot - in twp places.

Not really to do with Four stroke cycle.

Roger

It’s called compression Roger 

[RobH]

15 minutes ago, ntc said:

It’s called compression Roger 

Yes that is the basic cause Neil but it doesn't matter whether the engine is a 4-stroke or a 2-stroke; compression occurs at the same point on the crank rotation regardless. I expect that was what Roger meant.