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 Post subject: Starter not engaging
PostPosted: Tue Jan 15, 2019 12:14 pm 
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848cc
848cc

Joined: Thu Dec 06, 2018 12:08 pm
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Location: Sydney
Hi guys.
I've just finished wiring up my mini and the starter isn't engaging as it should.
The wiring diagram says that one terminal of the starter should get power from the switch and the second terminal should be grounded, however there is only one terminal on the old style starter. i'm reluctant to put a ground on the same terminal as the power unless that is the way to go.
I have rigged it up as per the wiring diagram without any ground and the starter spins, although not enough to engage.
The wiring should be fine as all the dash lights and the fuel pump are working.
Bellow is a link to the wiring diagram
https://www.minimania.com/images/wiring ... ring06.pdf


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 Post subject: Re: Starter not engaging
PostPosted: Tue Jan 15, 2019 1:07 pm 
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848cc
848cc
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Joined: Thu Sep 17, 2015 9:25 pm
Posts: 178
Location: Brisbane
Peter,
What model Mini are you working on, can I assume an early model with starter solenoid/switch inside the car on the floor?
The starter is earthed by being bolted to the clutch housing/engine.
Clive

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 Post subject: Re: Starter not engaging
PostPosted: Tue Jan 15, 2019 3:56 pm 
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1275cc
1275cc

Joined: Sat Feb 09, 2013 5:44 pm
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Location: Camden
petermk1 wrote:
.................
I have rigged it up as per the wiring diagram without any ground and the starter spins, although not enough to engage.
https://www.minimania.com/images/wiring ... ring06.pdf


Do you mean there is not enough power from the battery to spin the starter fast enough - or is the Bendix drive and gear sticking on the starter shaft?

The power lead to the single terminal post on the starter motor is a thick battery cable type lead, from either the push button switch under the floor for early minis or from the solenoid switch for key-start minis.


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 Post subject: Re: Starter not engaging
PostPosted: Tue Jan 15, 2019 4:12 pm 
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1360cc
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Location: Melbourne, VIC
A previous post of his says it's a 1964 model.

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 Post subject: Re: Starter not engaging
PostPosted: Tue Jan 15, 2019 4:29 pm 
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1275cc
1275cc

Joined: Sat Feb 09, 2013 5:44 pm
Posts: 2176
Location: Camden
The wiring diagram you have is a bit misleading as it shows 2 terminals on the starter motor with 1 going to earth. Most diagrams would show the whole unit as being earthed.
Don't add an earth lead ; as "cgo" said, it earths through the housings.


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 Post subject: Re: Starter not engaging
PostPosted: Tue Jan 15, 2019 4:45 pm 
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848cc
848cc

Joined: Thu Dec 06, 2018 12:08 pm
Posts: 20
Location: Sydney
Thanks guys.
Yeah its a 1964 850 mk1 and it is an old floor starter button without a solenoid from what i gather from the diagram and my research. I initially tried running a solenoid between the switch and the starter to avoid damaging the starter, and the starter barely spins, when I took out the solenoid as per the wiring diagram the starter spun much quicker however it wasn't quick enough to engage the inertia cog. I tried it with my daily's battery just to be sure but with much the same result.
I am using T H I C C battery cable from the batery to the starter.
And to answer bills question it seems there isn't enough power from the battery

Cheers


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 Post subject: Re: Starter not engaging
PostPosted: Tue Jan 15, 2019 5:50 pm 
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1275cc
1275cc

Joined: Sat Feb 09, 2013 5:44 pm
Posts: 2176
Location: Camden
You don't need to add a solenoid, as the push button switch is doing the same job directly as a solenoid would do electrically - it connects the battery power to the starter motor.
If the Bendix drive and gear at the end of the starter shaft is free to spiral up and down the thread it runs on, that is starting to sound like the starter has internal problems like worn brushes or bearings. Can you borrow a working starter motor to compare?


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 Post subject: Re: Starter not engaging
PostPosted: Tue Jan 15, 2019 7:10 pm 
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848cc
848cc

Joined: Thu Dec 06, 2018 12:08 pm
Posts: 20
Location: Sydney
The starter is brand new so there shouldn't really be any issue unless it is a factory error. As for the bendix drive being free to move up and down, I didn't check before installing it so that will be a good first step as it does sound like it is spinning pretty quick.
It is also possibe that both batteries are a little unhealthy as one has been sitting around for a while and my daily driver one is pretty old, I'll have to find my multimeter and give them a test.
Either way this has given me a good place to start. Thanks for all the help guys, I really appreciate it. If I still run into problems I'll repost on the thread.


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 Post subject: Re: Starter not engaging
PostPosted: Tue Jan 15, 2019 7:59 pm 
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1275cc
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Location: Wollongong
Check it spinning in the right direction. (I don’t know if it is even possible for it to run backwards unless faulty).

Is the car set up as neg earth or pos earth.



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 Post subject: Re: Starter not engaging
PostPosted: Tue Jan 15, 2019 9:07 pm 
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just to add a dumb question - have you fitted the earth strap from the engine to the body?

I'd be putting the battery in front of the car and getting the jumper leads out, connect the negative to somewhere on the motor that has good earth (like one of the flywheel housing bolt heads) and touch the positive to the terminal on the starter motor. If it doesn't spin then you have a dud starter motor. If you don't want to do it in the car, it's only 2 bolts to take the starter motor out and test it in a vice

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 Post subject: Re: Starter not engaging
PostPosted: Tue Jan 15, 2019 9:58 pm 
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1275cc
1275cc

Joined: Sat Feb 09, 2013 5:44 pm
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Location: Camden
Good advice from simon k for easy checking. It is sounding like a problem starter motor.
All starter motors work on Neg or Pos earth. They are not polarity sensitive so that is not an issue.

Where about are you in Sydney if you want help some someone?


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 Post subject: Re: Starter not engaging
PostPosted: Wed Jan 16, 2019 10:08 am 
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848cc
848cc

Joined: Thu Dec 06, 2018 12:08 pm
Posts: 20
Location: Sydney
Hey guys. that worked a treat. I took the plugs out and rigged it up and it cranked well. unfortunately water poored out of cylinder 3 and 4 although when i did a leak down test the compression seemed to be on the higher side of things. For now I'll crack on, drain the cylinders, hope for the best, e.t.c, but I'm thinking itll probably be a new head gasket job if not a busted engine.

Out of the pan and into the fire. thanks though guys, at least it cranks haha


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