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Starter Solenoid Failure
Ivan - 27/2/21 at 02:32 PM

In fifty odd years of driving I have never had a starter solenoid failure - now I have had two in as many years on the same starter. Symptoms are that starter motor runs continuously without bendix engaging as soon as ignition is switched on. Have checked bendix and it works smoothly and easily without sticking.

Anybody know why this might be happening. Battery is fully charged and more than adequate power leads to and from motor so low voltage not a likely problem.

This is happening on a high torque geared starter for a Chevy V8. The first time I thought it might be the country of origen (Unbranded) the second time not so much as it is a Unipoint one and looking at my third one (A bosch one) it looks like they both come from the same factory..

[Edited on 27/2/21 by Ivan]


steve m - 27/2/21 at 03:44 PM

Starterman on here is the best person to ask, he will be along soon


Ivan - 27/2/21 at 04:55 PM

Thanks - looking forward to his comments if he replies. One of the things I just thought of is to put a voltmeter across thew main terminals of the solenoid to check voltage when starting. The only place where their could be a weakness causing current drop is in the main battery cutoff switch.


starterman - 27/2/21 at 06:09 PM

First thing I'd check is your voltage and the condition of your terminals. If they are all good then I'd maybe try a relay before the solenoid. I get quite a few of these type of issues on agricultural and plant machinery.


02GF74 - 27/2/21 at 08:25 PM

Bendix starter use centrifugal force to throw the thingy so it engages with the teeth in the flywheel.

Higher torque is achieved in 2 ways, either by a larger motor or by gearing down.

I don't know what starter you have fitted, but the high torque starters I've seen ue same size motorbut gave a gearbox t be geared down. Gearing down means the final drive turns slower hence lower force and probably where the issue lies.
. Check the bendix is in good condition, no burrs or wear and lubricated with light oil.

Check and clean all power connections, fit an earth from motor to the battery terminal.


Ivan - 28/2/21 at 10:03 AM

Thanks for input all - I will check voltages at battery and starter when cranking - the starter is a high speed motor geared down to increase torque (one advantage is it weighs half of old starter - it really spins the motor very well. Standard starter wouldn't spin the highish compression 500+hp stroker motor. (383 Cu Inch Chevy V8.)


02GF74 - 28/2/21 at 06:13 PM

^^^ it can't spin it as fast as the original as that would defy the laws of physics.


rusty nuts - 28/2/21 at 07:10 PM

quote:
Originally posted by Ivan
Symptoms are that starter motor runs continuously without bendix engaging as soon as ignition is switched on.



[Edited on 27/2/21 by Ivan]


Do you mean when the ignition key is turned to the start position ? or just with the ignition turned on ?
If it is the latter you have a wiring or ignition switch fault


Ivan - 1/3/21 at 04:22 PM

The wiring is direct from battery to cutoff switch at the back of the car close to battery (Less than a foot from battery) then cutoff switch to solenoid +ve terminal (No ignition switch in between). The starter switch is wired to third terminal on solenoid and when activated closes the circuit across the solenoid to activate the starter motor and the bendix.

Yes the starter spins the engine faster because it is a high RPM motor geared down to provide extra torque whilst still spinning the engine faster than the old starter.

As best I can tell the contacts in the solenoid are stuck closed even though the solenoid coil is un-powered thus feeding power to the starter motor but not activating the solenoid coil and hence activating the bendix. This happens whenever the main feed from battery is switched on and has nothing to do with the ignition switch. The coil in the solenoid only activates when the starter switch is turned on.

[Edited on 1/3/21 by Ivan]