[tc]

I am going to use a relay to power my starter solenoid. I could use a 60 amp bosch style relay or the bigger ford type. If I use the ford style (that is called a solenoid), I see some that are rated at 15 amps.

200 amps would be needed, if used to power the starter with a jumper to the starter solenoid and that 200 amps would pass through the ford style relay. Even the starter solenoid could draw 30 amps when hot if wired only to the starter solenoid.

So, what does the amp rating ( 15 amps ) on these ford style relays ( solenoid ) mean? Do I need to find one with a 200-250 amp rating?

[stellar]

The 15 amps is probably the draw. (what it takes to energize the solenoid) As you said the delco solenoid on your starter can draw 30 amps or even more. If you are only going to use a relay to energize the delco solenoid at the S terminal the 60 amp bosch would be fine. If you want to use the ford solenoid to do the same thing it would also be fine, but a bit of over kill. If you want to connect the S terminal to the positive terminal at the starter solenoid, you will need to use the ford solenoid. This will make the heavy wire to the delco solenoid from the ford solenoid dead ( no voltage) until the ford solenoid is energized through the ign switch. The ford solenoid can carry well over 500 amps to feed the starter and solenoid.

[tc]

Thanks
I have a bunch of 40 amp bosch style relays. Do you think it's hard on the relay if the current draw is 30 or even 35 amps.
Also, do you know of a good place to buy a connector for the bosch relay? Something mountable, to easily pull the relay to prevent starting the engine?

[b-man]

My Ford solenoid never let me down, that along with 2/0 welding cable to make my battery connections. I used a copper buss to connect the solenoid to the hot cable.

Always started with a flick of the key no matter the weather, used a stock recurved points distributor and a stock coil too.

This was my daily driver for 5 years and 30k miles, a 455 with 8.2:1 compression with the 068 cam. It was as reliable in daily use as a stock Pontiac, because it was.

Never even so much as lifted a valve cover, how it should be.

[george kujanski]

I added the Ford-type starter relay to my '67, primarily because I didin't want a hot bettery cable going down to the starter past the exhaust manifolds. Additionally, it provides a handy access point to bump the starter when doing some maintenance.

Another story... I have a '91 Allante with the dreaded Italian electrical system....not as bad as Lucas, but switches going bad, etc. In any case I was having a problem with the starter solenoid triggering using the key normally, So I added a BOSCH relay to drive the starter solenoid directly from the battery, controlled by the key circuit. Fixed the problem by the key circuit not needing to pass the 15 Amps or so required by the starter solenoid. Now it just operates the coil of the Bosch relay, prob less than an amp.

BTW, a while back I bought a package of the relays along with plug-in harnesses. I can check later today if I kept the invoice.


George

[tc]

I can buy these, but would like a mountable relay harness.. I can make something to encase the harness. The harness's I have seen have small wires on them. This harness list as:
60/70/80A @ 14 VDC
Coil Wires - 18 AWG, Contact Wires - 13 AWG
Why such small gauge wires for high amperage rating?
Also, is this relay enough amps? The open/close ratings?

[Bill Hanlon]

The wiring chart I use says that an 80 amp load needs a minimum of 10 AWG wire and no more than 5' of length.

That said, the relay would probably melt if pin 30 ever had anywhere near 80 amps flowing through it.

Most of the high amperage cube relays I've seen proudly advertise on the case that they are 30, 40 or 60 amp capable. Yours has no such advertising. Usually the amperage rating will be something like 40/30 where the higher current rating is for the normally open contactor (87) and the lower rating is for the normally closed contactor (87a).

[tc]

The amperage rating is on the relay. open-60/80, close-40/70. I suppose the close rating is high enough for 30-35 amps a hot starter solenoid could draw.

My mini starter states to not put a jumper between the motor wire stud and the solenoid wire stud. Don't know why as both of those studs draw voltage from the battery-same source. Guess I could google why. That is the reason I am looking at a relay instead of the ford style solenoid connected to the starter motor.

[stellar]

I didn't know you had a mini starter. If the mini states not to jump the sol.Pos post to the S post it is probably a permanent magnet starter. The permanent magnet starter can stay engaged for a few seconds after releasing the key. If you have an electromagnet starter you should be OK.

[Bill Hanlon]

Sorry TC. I should have paid more attention.

[tc]

No problem, happy for the help. This is all new to me. Wish the connector shown above had larger gauge wires on it.

[Geoff]

With the purchase of the Ferd sol, you get a free dynosaur.....
Big, ugly & overkill. The GM starter pulls about 55 amps on the pull in winding & about 30 amps on the hold-in winding. Most mini starters use less than this. I use a Bosch type relay. I have one on my GTO, 60 amp contact rating.

[Geoff]

Just to follow up on my previous post....
My understanding is the the horrendously horrible Ford sol was reqd with the Ford Folo-thru starter. This starter did not have the usual sol mounted on the starter sol, hence the need for a separate heavy duty sol to switch the heavy starter current.

[tc]

Another question. The terminal with the two tabs shown below, would have the ignition switch attached one tab. Can I hook up a push button switch, to crank the engine from outside the car, to the other tab? That would put 12 volts back into the ignition switch wiring when I push the button, is that ok?

[Bill Hanlon]

If the other side of your push button switch was hooked to 12v that was available when the key was off, yes it should cause your starter to engage and turn. The engine should start as long as you hold the push button in and quit when you release the button.

[DogMeister]

I'm using a Ford-style starter relay (solenoid) on my 2nd GTO, worked for years on my first one, completely eliminated the hot start issue. I wouldn't use one of those little Bosch-style ones. Go big or go home.

[tc]

Even if I used the ford style, I would have the same question. Using a push button ( to crank, not start the engine, key off ), one wire to the battery and the other wire to the same post ( ford solenoid or relay ) the ignition switch wire is hooked to. Pushing the button would cause voltage in the ignition switch wiring ( going backwards? ) all the way to the ignition switch. Will that hurt the ignition switch or neutral safety switch on my auto shifter? Do I need a diode on the ignition switch wire that triggers the relay?

[DogMeister]

Originally Posted by tc

Even if I used the ford style, I would have the same question. Using a push button ( to crank, not start the engine, key off ), one wire to the battery and the other wire to the same post ( ford solenoid or relay ) the ignition switch wire is hooked to. Pushing the button would cause voltage in the ignition switch wiring ( going backwards? ) all the way to the ignition switch. Will that hurt the ignition switch or neutral safety switch on my auto shifter? Do I need a diode on the ignition switch wire that triggers the relay?

They make an auxiliary switch that attaches to the Ford solenoid so you can crank it from the engine compartment, ignition on or off. You can also jump the terminals with a screwdriver. People have been doing that since the system began. Never heard of it causing an issue. The current is going to take the shortest route. If the ignition/starter switch is open (not on) no current is going to flow to it.

[Goatracer1]

I think you are over thinking this. You are not replacing the starter solenoid. All you are doing is by passing the start circuit from the ignition switch to the solenoid on the starter. You can do that with either the Ford unit, a Chrysler starter relay or an after market relay depending on how you wire it. The Ford unit just eliminates the purple wire to the terminal on the starter. Using either of the other two ways you still need that wire but now it runs from the relay not the starter switch.

[Bill Hanlon]

Originally Posted by tc

Will that hurt the ignition switch or neutral safety switch on my auto shifter? Do I need a diode on the ignition switch wire that triggers the relay?

I don't think it would "hurt" anything unless your car has a manual transmission. If it did, have a stick it might hurt you when it pinned you between the bumper and your garage wall.

A diode would solve the problem of backfeeding the IGN2 circuit of the ignition switch.