[DeTomaso] starter electrical system problem

Jeff Cobb jeffcobb1 at me.com
Sun Sep 22 15:26:01 EDT 2013

The bendix.
All starters must have a bendix drive setup that allows contact only while cranking with the flywheel. 
Two types are: 
1-The centrifugal bendix drive type that old cars used sat on a helical cut spine arrangement of the starter shaft that shoots away from the starter against spring pressure and contacts the flywheel as the starter motor spins, a knee jerk reaction. Just rebuilt one last week on a 56 T-Bird. The flywheel speed will then overspeed the helical and starter speed and design will allow non gear interface.
2-The solenoid type that electomechanically shoves the gear drive into the flywheel and will mechanically deactivate by a one way spray clutch. That way the flywheel cannot turn the smaller gear into dust.

You can still use a Ford type non starter body mounted solenoid to fire a starter that has its own on body mounted solenoid, this will help cure a slow starter speed when hot and/or under heavy cranking loads. 
In the past we would convert Peugeot, Cadillac and Blazer diesels and high performance Chevys to this double solenoid configuration.

A Ford off starter body solenoid and relays are electromechanical relays. The mechanical contacts flow the higher amps once activated by the trigger feed.

When the solenoid is not mounted on the starter it acts more like a relay than it mechanical function when starter body mounted.
An automotive relay can rarely handle more than 50 amps whereas a starter solenoid/relay can handle hundreds of amp load.

Hope this helps

Jeff Cobb

On Sep 22, 2013, at 1:29 PM, Pantdino <pantdino at aol.com> wrote:

> Ok, for my education:
> Two things have to happen when you engage a starter motor:
> 1) the starter motor gear has to be engaged in the teeth of the flywheel
> 2) the starter motor has to turn
> AFAIK the starter motor is not engaged all the time with the flywheel.
> So what are you calling the thing that moves the starter motor gear out to engage the flywheel if its not a solenoid?
> -----Original Message-----
> From: MikeLDrew <MikeLDrew at aol.com>
> To: pantdino <pantdino at aol.com>; jeffcobb1 <jeffcobb1 at me.com>; boyd411 <boyd411 at gmail.com>
> Cc: detomaso <detomaso at poca.com>
> Sent: Sun, Sep 22, 2013 11:06 am
> Subject: Re: [DeTomaso] starter electrical system problem
> In a message dated 9/22/13 10 30 32, pantdino at aol.com writes:
>> The relay is on the firewall, while the solenoid is that big bump on the starter motor.
>> No?
> >>>No.  At least, No if you have a standard Ford starter.  A solenoid is a relay on steroids, and in a stock Pantera setup, the solenoid is on the firewall.
> From Wikipedia:
> "... a solenoid switch, which is a specific type of relay that internally uses an electromechanical solenoid to operate an electrical switch; for example, an automobile starter solenoid, or a linear solenoid, which is an electromechanical solenoid."
> Modern starters incorporate the solenoid onto the starter itself.  Some people will keep the stock Ford solenoid on the firewall and just use it as a trigger to actuate the solenoid on the aftermarket starter.
> If you have a stock Ford starter, that big bump is...a big bump.  I honestly don't know what it is.  But it ain't the solenoid.
> Mike

More information about the DeTomaso mailing list