MTFCA Forum

I have what I guess is a curiosity question, reviewing voltage used for the starter circuit.
Previous to knowing better, I used 12 volts on two well driven cars for years, without any modification to the starter. Both cars had alternators.
We ran both of these cars for many years without damage to the bendix spring. Both cars started very easily and quickly when the starter button was pushed. Both cars were equipped with starter solenoids.
My question is: is damage done to the spring on initial engagement of the high voltage start or is it done as the result of the starter being engaged for more than a couple of seconds? I wouldn’t think so; but does the solenoid some how “cushion” the initial bendix engagement thus reducing the damage to the spring?
Our two other cars run on six volts, start easily and quickly and use a solenoid. The bendix springs appear to have little or no issues with this set up, basically as new, with the exception of the solenoid. Main wires from the battery to the solenoids and to the starters are as supplied by the vendors, regardless of the voltage being used. All the above mentioned cars are equipped with z heads.
Thanks
Tom

The initial contact with the ring is what causes the damages, because it is much faster and hits much harder. It can damage the spring and also the gears.
Norm

"...does the solenoid some how “cushion” the initial bendix engagement..."

Tom,

I don't believe it would have any effect.

Using a solenoid would not "cushion" the starter action when applying 12 volts to a 6 volt starter. It would prevent stepping on the starter by mistake and would assure a positive electrical and mechanical engagement. A failure to step firmly on the starter switch, or a starter switch in poor mechanical or electrical condition, can cause poor engagement, multiple engagements, or aborted starts, which increase wear on the starter assembly. A solenoid will give a quick, positive starter engagement every time, which will extend the life of the starter assembly and prevent ring gear damage. Using two identical 6 volt batteries in series with a tap on the connection between them could provide a split 6 and 12 volt system. 12 volt charging equipment would be necessary, and a solenoid to allow connecting the starter to the 6 volt tap would be advisable. More trouble than it would be worth, I'd think, besides the expense and space it would require.