56 Starter Relay

[BJK]

Found a few posts mentioning starter relays, and one talking about a conversion from a generator to an alternator. While that thread (early 2005) talked about my problem it wasn't specific on the solution.

I am converting my 56 Roadmaster from a generator to a one-wire alternator. When making this conversion I assumed that the Generator Regulator is no longer needed since its primary function was to control the behavior of the generator.

As previously mentioned, if you eliminate the Generator Regulator, you have an 18 guage Light Green wire running from post #3 on the Starter Relay to no-where. Previously this ran to the GEN post of the Generator Regulator.

According to my shop manual, when the current regulator portion of the Generator Regulator is not operating (no or very low current flow from the generator) the contact points are closed which results in the generator field circuit being directly grounded. Since the Light Green wire above is connected to the GEN post, this means that this wire is supplying ground to the Starter Relay when the Generator is not operating.

From that description I assumed that I could eliminate the Generator Regulator and then connect the Light Green from Starter Relay #3 to ground. When the "push-to-start" circuit is activated, power is supplied to Starter Relay #4. By grounding #3, I will have achieve the same result as originally designed and the magnet in the Starter Relay will cause the relay to close allowingcurrent, being fed from the ignition switch to #1 on the Start Relay, to flow to my starter solenoid via #2 on the Starter Relay.

In the thread from early 2005, folks stated that they "eliminated" the connection to #3 (starter relay ground). They also stated that they relied on the vaccum relay, which is part of the "push-to-start" circuit to cut power to the starter once vaccum build up.

Just a couple of quesitons.

1) Does anyone agree with my view that I only need to ground #3 on the Starter Relay for that circuit to work properly?

2) Does relying on the vaccum switch to cut power to the starter, since this is already part of the neutral safety switch circuit, make anyone think I will have problems later? I can see that if I loose vaccum with the engine running this switch will close and I will have current flowing to the starter relay which would now cause the starter to engage, where in the original system the current flow from the alternator would have prevented this.

3) Am I wrong about not needing the Generator Regulator?

4) What did I miss?

Thanks in advance for suggestions/comments.

Bob

[rcull]

This may be what you are looking for...

http://www.buicks.net/techref/ftecref14.html

[BJK]

Rcull,

Thanks for the pointer but the info there is for a three-wire alternator. It does a good job of decribing the changes needed to support it but it doesn't help me with my Start Relay issue.

Also the 4-wire description of the Voltage Regulator isn't close to the 5-wires I have on the old 56 Generator Regulator.

Bob

[rcull]

Mmmm...

I don't know, but the '57 wiring diagram shows only a 4 terminal regulator with a five wires. The 14 red and 10 red are tied together.

It appears the 18L Green which to the starter relay is the power wire which should always have power after the key is on. You could check it by disconnecting it and checking for power at the relay terminal, I expect that terminal is hot, if not turn the key on and check it again. It supplies power to activate the relay in the circuit for stating the car with the accelerator switch (probably grounds the relay).

Probably if you find a battery junction block there is a smaller wire which runs to the RUN side of the starter solenoid. Try hooking the green wire here or go directly to the run side of the solenoid.

If you doing this without tools, when everything is disconnected, hook the batt back up. Have someone hold the accelerator pedal in the start position, nothing should happen touch the green wire wire to terminal one and the starter should engage.

Remember, that's just what it looks like to me with the '57 manual

[BJK]

rcull,

Sorry for not getting back to you -- you were right about the fact that the green wire is part of the circuit that closes the relay that sends power to the starter solenoid. If I ground this wire I get a starting car -- without ground nothing.

After playing with it, and studying the 56 wiring diagram more, I decided that it would be a wise thing to put this ground on a switch for the time being. When I want to start I close the switch (provides ground to the starter relay) and after it is started I open the switch (removes ground).

Since the "push to start" mechanism relies on vaccum, I became concerned that if I "stepped on it" I might get a situation where I loose enough vaccum where the starter relay might try to do its thing. Since I wasn't too keen on the idea of my starter trying to engage a running engine I decided the switch was the best "temporary" solution until I can devise a better ground that would open when the engine is running.

Thanks for the advice.

Bob

[Jim Carmichael]

The green wire is the back up safety for the vacume switch and cuts power to the starter when the generator is charging to prevent just what you mentioned. It is a good idea to do as you said and put it on a switch but there is a way to do it automatically however I don't remember which post that was in.

[BJK]

Jim,

I searched and didn't find any mention of an automatic way to sense power to "open" this ground circuit. I would REALLY appreciate it if you keep it in the back of your mind and let me know if you do come across it.

Thanks
Bob

[soulbrother]

I did that conversion three years ago on my 1955 Special and have since been relying on the vaccum switch to cut out the starter when engine is running. Never had a problem with it!
There is a way I found out to use a couple of relays to get the charging signal to cutout the starter switch circuit if not using the old relay. I wired it up on my other Buick -55, a Century and it works perfect!
If I find the wiring diagram I made for it I´ll get back to you!

[BJK]

Hey soulbrother,

Would much appreciate the wiring diagram.

Good to hear that the vaccum switch isn't as sensitive as my meter claimed it was. Maybe I am being just a little over-pairinoid there -- but I've had starters stay engaged in the past on a running engine and just imagining the noise again makes me cringe.

Thanks
Bob