[TR] Yeah, I know, the Overdrive...Again....

[Reihing, Randall S.]

Recently I had occasion to work on a 1980 Oldsmobile Cutlass with GM's failed diesel engine. The starter was unresponsive and I traced it to the factory original solenoid. When I removed it's cover I discovered two sets of very heavy duty brass contacts whose purpose was to complete the electrical path through the coil so the relay could function. Interestingly the solenoid was using only one half of the set of dual contacts for the electrical connection to the starter. The way the relay was constructed allowed me to simply reverse,or switch the contact points themselves around so the active side of the solenoid relay now had two brand new contacts for the electrical path to the starter. Once the "good" contacts were in position the solenoid energized and the car instantly started.

Randall Reihing
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From: Triumphs [triumphs-bounces at autox.team.net] on behalf of Randall [tr3driver at ca.rr.com]
Sent: Sunday, July 23, 2017 9:30 PM
To: Tom Walling; triumphs at autox.team.net; TERRY SMITH
Subject: Re: [TR] Yeah, I know, the Overdrive...Again....

> Cars built back when your TR3 was don't have diodes anywhere in them.
> Heck, even the radios were tube-type not the new-fangled transistor kind.

Quite true, I did not mean to imply the diode was original in any way. The diode is purely a workaround to the problem I had.

My guess is that the original relays used a different contact material that was more resistant to the effects of the spark. Perhaps silver or even gold plated silver. Tungsten is another possibility.

Today, solid state diodes are common and cheap. Many automotive relays even have them incorporated, to protect Solid state ECU drive circuits. So I'm guessing that even the reproduction relay I got used less expensive contacts that are less resistant to arcing.

But all I can say for sure is that it worked for me.

If you are worried about a concours judge spotting it, you could always hide it under the solenoid cap. At the relay was just a lot easier place for me to access. And my TR3 is definitely a driver, not a show car.
-- Randall
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