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Tech / General EngineIs your car making a strange sound or won't start? Thinking of adding power with a new combination? Need other technical information or engine specific advice? Don't see another board for your problem? Post it here!
Hi guys.
Im finishing up my zz6 crate engine with first intake combo and was planning on useing my stock 305 starter. Only problem was i damaged the solinoid when i removed it so im going to have to replace it with a new one. From what iv seen online stock gm starters have 3 connections on them but my original only had 2, strange maybe because its a hei distributer i have no idea. Anyways the new mini starters seem to only have 2 connections on them aswell so im wondering if i can use a mini starter ?.
I have no idea about wireing but it looks like my original had a purple signal wire and the rest were on the other terminal im guessing power.
Any help would be awsome.
Pretty much all starters only have 2 connections. The other "connection" is an external jumper cable from the solenoid to the actual electric motor.
The two connections you have will be for the battery cable (large diameter) and the fusible link wires that feed the accessory circuits - that's the big-un with the M8 nut on it.. The other small connection will be for ONLY the purple solenoid wire - this is what actually engages the solenoid - that's usually a tiny nut or a spade.
That looks repairable - needs to solder on a spade or something..... but I would highly recommend a mini starter. One of these will do for ya:
..... From what iv seen online stock gm starters have 3 connections on them but my original only had 2, strange maybe because its a hei distributer i have no idea.......
Yes indeed , pre HEI distributor GM vehicles did in fact have two small connections to the starter (along with the big one for 3 total) , instead of the one small connection seen on our third gens . Our one small connection , as you know , is labeled "S" and has the purple wire connected to it that energizes the solenoid when you turn the key to start . On GM cars old enough to have points (non electronic ignition) the other small terminal was labeled "R" and it's purpose was to supply full battery voltage to the ignition coil while the starter operates . In normal running the coil was supplied power through a resistance wire , it's this resistance that the "R" terminal eliminated during cranking , ensuring a hot spark for easier starting . Once the engine started and the starter solenoid disengaged , the "R" terminal stopped supplying full battery voltage to the coil , which went back to being powered by the resistance wire .
Even if you ended up with a starter with the extra terminal , as long as that starter is exactly the same as yours except for the extra terminal , you can use it just fine . As usual your purple wire will go to the "S" terminal , and nothing will go to the "R" terminal .
Last edited by OrangeBird; Jun 4, 2019 at 02:15 PM.
Interesting RE: The ballast resistor bypass being in the starter solenoid. Wonder why they didn't just use the 12v to the starter motor for that? Seems like it's the same thing......
What they did was , the coil was designed to work on 10.5 volts , the normal voltage a 12 volt battery sags to while supplying the power to the starter to crank the engine over . The ballast resistor (a resistance wire for GM & Ford and an actual ceramic resistor for Chrysler) accommodated the 3 volt difference between the coil's 10.5 need and the running car's 13.5 (ish) supply . My only possible guess as to why they would use the solenoid to switch the ballast in and out of the circuit would be that the "R" terminal gets it's power from the same copper ring in the back of the solenoid that hits the contact that drives the starter motor itself , being that close to where the big amps are would mean the least loss possible when every volt counts .
Right..... I guess I meant the ~4AWG wire that goes from the solenoid to the motor. That BIG terminal with the external cable..... well now that I'm thinking about it perhaps that was internal not external like a modern mini-starter. You know - that 2.5" long wire that connects the solenoid output to the electric drive motor? If that was internal on those old starters then yeah I can see why you would need an R terminal to get at it.
Interestingly my mom's 56 Buick Roadmaster has a resistor mounted on the coil. Looks like it's made from nichrome wound wire. I actually chased down a new old-stock one for it as it was suffering from age related deterioration.
GD
Last edited by GeneralDisorder; Jun 4, 2019 at 06:32 PM.
Right..... I guess I meant the ~4AWG wire that goes from the solenoid to the motor. That BIG terminal with the external cable..... well now that I'm thinking about it perhaps that was internal not external like a modern mini-starter. You know - that 2.5" long wire that connects the solenoid output to the electric drive motor? If that was internal on those old starters then yeah I can see why you would need an R terminal to get at it.
Interestingly my mom's 56 Buick Roadmaster has a resistor mounted on the coil. Looks like it's made from nichrome wound wire. I actually chased down a new old-stock one for it as it was suffering from age related deterioration.
GD
Hi GD , The reason they couldn't do that is that the ignition coil would backfeed through the starter's windings when the starter was not engaged . The R terminal is the "cold" side of the switch formed by the copper washer and the heads of the studs that become the threaded terminals on the outside back of the solenoid . The coil has to have power in both crank and run , whereas the starter motor has power in crank only , hence the isolated R terminal that is exclusive to the coil .
Thanks everyone for all the info. Now i can get this starter replaced.🍻🍻
I'm happy to have been able to help . The biggest thing for small block chevy starters is how many teeth on the transmission they are to engage to (something like 153 teeth VS 168 ? teeth , not sure on the exact numbers) and the bolt pattern where they bolt up to the block , straight in a line or offset . Rest assured if it's dimensionally correct (same # of gear teeth and same bolt pattern) and has the extra terminal you'll have no problem .
Hi GD , The reason they couldn't do that is that the ignition coil would backfeed through the starter's windings when the starter was not engaged . The R terminal is the "cold" side of the switch formed by the copper washer and the heads of the studs that become the threaded terminals on the outside back of the solenoid . The coil has to have power in both crank and run , whereas the starter motor has power in crank only , hence the isolated R terminal that is exclusive to the coil .
Oh yeah that makes sense! I hadn't though of the coil feeding into the motor windings when the motor isn't energized. That would make for a really interesting effect I bet. For a short time anyway.
Sorry just checked back in.
Been busy with a fuel leak in the fuel rail. I damaged the rail accidently due to over tightening the fitting in the end of the rail and im waiting on new ones arriveing from first. thanks for all the info its been a massive help. Im in australia so i got a hi torque mini starter from a local place
