Weak starter motor?

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Mr B
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Weak starter motor?

Post by Mr B »

Evening all,

So go to start my car and at first she cranks quickly but then she starts cranking in what I can only describe as spasms - as if the battery is going flat, this happens regardless of what battery is on the car, I adjusted the timing thinking she may be a bit too advanced but nope still the same, it's a 3.1 Essex V6 with Powermax pistons which I believe have much higher compression than stock pistons. Weak starter motor?

What do you guys think?

Wayne
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Mc Tool
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Re: Weak starter motor?

Post by Mc Tool »

Aye Wayne , my pinto does the same ,usually only for the first cold start of the day. I est my comp to be about 9.75:1,it doesnt really hack 96 fuel ,even with timing set a 4deg , goes much better on 100+. I have tried 2 different starters and eliminated battery/lead faults too. I think one of them gear reduction hi torque starters is the go , they sound real cool to πŸ™‚
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Re: Weak starter motor?

Post by Mr B »

Mc Tool wrote: ↑Sat May 22, 2021 11:27 pm Aye Wayne , my pinto does the same ,usually only for the first cold start of the day. I est my comp to be about 9.75:1,it doesnt really hack 96 fuel ,even with timing set a 4deg , goes much better on 100+. I have tried 2 different starters and eliminated battery/lead faults too. I think one of them gear reduction hi torque starters is the go , they sound real cool to πŸ™‚
Hi MC,

Thanks for replying, the high torque starter motors are good, the only issue is that they don't have the provision on them that sends 12 volts to the coil under cranking conditions, easy enough to wire in a separate switch in though.
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stevemarl
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Re: Weak starter motor?

Post by stevemarl »

Mr B wrote: ↑Sun May 23, 2021 10:33 am the only issue is that they don't have the provision on them that sends 12 volts to the coil under cranking conditions, easy enough to wire in a separate switch in though.
Just use a relay from the starter so it switches automatically?
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Re: Weak starter motor?

Post by Mr B »

stevemarl wrote: ↑Sun May 23, 2021 11:29 am
Mr B wrote: ↑Sun May 23, 2021 10:33 am the only issue is that they don't have the provision on them that sends 12 volts to the coil under cranking conditions, easy enough to wire in a separate switch in though.
Just use a relay from the starter so it switches automatically?
Steve,

Correct me if I'm wrong but on the standard starter motor there are small wires that go to the solenoid, am I right in saying that one of those wires is in fact a feed of 12 volts from the solenoid to the coil under cranking conditions ?

Cheers

Wayne
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Mc Tool
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Re: Weak starter motor?

Post by Mc Tool »

Yup ,that terminal is internally connected to the switched side of the solenoid ,must be a way to get to this part on a hi torque starter .......or stick a 12v coil on it .
Trouble is ,is that these starters aint cheap ( for a good one )and Id sorta wanna know it had enough porridge before I buy it πŸ€”. Im going to need one for my Rover Capri .....just for clearance ......and I might have gone a bit silly with the comp ratio on that engine too @ 10.5:1, at least with grover all I have to do is change head gaskets and I can drop that to 9.75:1. πŸ˜€
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stevemarl
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Re: Weak starter motor?

Post by stevemarl »

Mr B wrote: ↑Sun May 23, 2021 8:56 pm there are small wires that go to the solenoid, am I right in saying that one of those wires is in fact a feed of 12 volts from the solenoid to the coil under cranking conditions ?
That`s correct, one will be from the start switch to energise the solenoid, the other will be to the coil, bypassing the ballast resistor wire
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Re: Weak starter motor?

Post by Major_Tom »

Battery earth to block gets my vote. Stick a jump lead from neg to bellhousing and see if that helps.

If not, stick a lead from positive to starter solanoid live and try that.
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Re: Weak starter motor?

Post by Peter-S »

Major_Tom wrote: ↑Mon May 24, 2021 9:34 am Battery earth to block gets my vote. Stick a jump lead from neg to bellhousing and see if that helps.
That's exactly how I resolved a similar problem on the 2.8. Everything seemed clean and tight but the jump lead proved otherwise. Changed the earth lead after that and all was fine.
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