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Starter Motor not Engaging


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Hi happy new year to everyone, and most of all lets hope its a healthy one.

Just tried to move the 4a out of the garage and the starter motor Bendix is not engaging just get the the whirring sound.

Have tried putting car in gear and rocking it, no good. Put a booster on the battery still no luck.

I had the starter motor, a standard original refurbished 5 or so years ago no problem since.

I remember when I took it off I turned the engine and inspected the teeth on the flywheel which all looked good.

I guess I will have to start by removing the S/M and inspecting it.

How can you tell if the ring gear be a bolt on or shrink on? is there any difference in the teeth?

Last thing I want to do is have to renew the ring gear on the flywheel big job I guess.

Any suggestions much welcomed.

Cheers Lee 

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HI Lee, happy new year to you,

re the starter, it sounds like the starter motor is functioning OK, my guess is the bendix has stuck. Engines always tend to stop in one of 2 places when turned off, usually as a piston comes up to compression, therefore each time the starter engages it tends to hammer the teeth in the same place on the ring gear. Easy check for ring gear missing teeth is to turn the engine over 1/4 turn which will bring a different part of the ring gear in line with the starter and try again. If it still does not engage it looks like starter out and check the bendix is moving easily. 

Sometimes also the starter solenoid contacts can become eroded and not pass a big enough belt of current through to the starter, so it may spin, but without that initial kick of inertia that is needed to flick the bendix gear into mesh. Same is true if there are bad contacts anywhere on the wiring from the battery down to the starter itself.

I would start by making sure all the battery (including the earth) connections are good. Likewise the connections on the starter solenoid, and the one on the starter itself.

Good Luck,

Ralph.

Oh, and if you have to take the starter out you should be able to tell if it is a bolt on ring gear cos you can see the end of the bolt holes in the flywheel.

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Hello again Lee

As Ralph has said most likely old dry or dirty grease has caused the Bendix to stick. I found this video that explains the principle of operation of the starter. May not look exactly like yours but way it operates will be the same. Take starter out, clean up the spiral bit (using turps or meths) so it runs freely. You may not even need to completely dismantle the moving parts. The video suggests using a dry lubricant. I have in the past used a tiny bit of thin oil as lubricant. Don't coat it in oil or grease because dirt will stick to it and it will seize up again.

https://www.youtube.com/watch?v=RhdSq4WOaDM

Good luck with everything.

Keith

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Got the starter motor off this afternoon and as advised the bendix was sticking so cleaned it up with meths.

Couple of questions, can I take the bendix unit apart by removing the split pin at the end of the very large spring or would I end up in outer space?

The top rear bolt was so hard to get to had to tape a spanner onto a long screwdriver to stop it turning must be an easier way,

Why is the return spring such a weak one ? as soon as there is a build up of crud on the spindle the bendix sticks.

Cheers for any advise

Regards Lee  

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Hi Lee,

 well done in sorting the the SM.

You should only require a light spring to push the bendix back as when the the engine spins up and the SM is de-energised the bendix will be spun away from the ring gear.  Just keep the bendix clean.

 

Roger

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10 minutes ago, RogerH said:

Hi Lee,

 well done in sorting the the SM.

You should only require a light spring to push the bendix back as when the the engine spins up and the SM is de-energised the bendix will be spun away from the ring gear.  Just keep the bendix clean.

 

Roger

Hello Roger - glad to see you 'advising' again.

Lee

As Roger has said the spring has to be light. I would recommend you leave the big spring alone and just keep the bendix clean. That means don't use grease or  lots of oil or dust will stick to it causing it to stick again. As for the difficult to get at bolts, I fitted a high torque starter motor and ended up making an inspection hole just so I could reach the fixing bolt from inside the car using a socket on an extension. Not ideal. Sometimes it is easier to access these things from under the car.

Keith

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Re, dismantling the Bendix, or drive gear, yes it can be done, see procedure courtesy of Haynes Manual

Ralph20220103_093603.thumb.jpg.8ba2a6811a24f87f65fc9ab4f016c6c9.jpg

20220103_093625.jpg

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Thanks Roger and Keith, I got underneath to remove the SM, I was surprised just how little dirt on the bendix guide will stop it from returning.

I will leave all alone and replace it as soon as I can.

May look at an inspection/access hole , did this on the side of the gearbox housing so now changing and re filling g/b oil a lot easier.

As time goes on its getting harder to climb about under the car.

Best regards Lee

 

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8 hours ago, Ralph Whitaker said:

Re, dismantling the Bendix, or drive gear, yes it can be done, see procedure courtesy of Haynes Manual

Ralph20220103_093603.thumb.jpg.8ba2a6811a24f87f65fc9ab4f016c6c9.jpg

20220103_093625.jpg

Could be bush 22 is worn to excess allowing the bending to deflect from where it should engage.   Have also come across bent shafts on high compression engines.

PM if you are going to restore repair the starter as I still have a small selection of NOS original Lucas starter motor spares.

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Thanks to all for your help / advise it proved to be just a build up of crud not allowing the bendix to return,

All working well now, might not be a bad idea to have a small hole in the flywheel casing so if it sticks again some dismantling fluid could be injected in.

Thanks Peter for the offer of spares I know where to come to in future if needed.

Cheers to all Lee

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