Starter solenoid and HEI current draw
 

This is for a pre-85 Camaro with carbed V8. I would like to know how many amps the fuses are on the starter solenoid and the HEI coil.

I wish I had a factory wiring diagram. I can figure it out if I had one. Can someone help me? I'm running custom wiring because I don't have a factory harness.

Thank you very much.

Re: Starter solenoid and HEI current draw
 

fusable links


use the ones on the car already


the HEI doesnt pull much, a 25 amp will work fine


this is what we use on the old points to HEI conversions before 1975

Re: Starter solenoid and HEI current draw
 

I wish I could. Like I said above. The car has nothing. No wiring. Nothing. If it had the factory wiring I would use it.

Thank you very much! That's exactly what I needed to know.

What about the starter solenoid? Would 30A suffice?

Re: Starter solenoid and HEI current draw
 

I measured the solenoid on a 1.4L engine once and it drew 40A so I would imagine a V8 starter draws at least that much.
Fusible links are available, or you can make them yourself. The general rule of thumb is that you use a 2" piece (or longer) of a guage 2 (or more) smaller than the wire it's protecting. The links you buy are insulated with something better than the usual PVC. If you get some silicon/ fiberglass insulated wire (for iron/ oven/ heater appliances) it should be safe.

Re: Starter solenoid and HEI current draw
 

Thanks for the info. You know I'm not big on fusible link. Right now I have everything running through the cabin and protected with fuses.

Unless I see some major advantage to fusible links my fusebox setup should be okay. My main issue is I don't want fusible links inside the cabin.

Re: Starter solenoid and HEI current draw
 

Yeah, you are right in not wanting those links inside the cabin.. Therefore they are placed in the most inaccessible location in the engine bay, down by the starter where they don't cause fuss if they smoke.. Hehe, no, the real reason is that you want the protection as close to the power source as possible, before the wire enters a loom or goes through the bulkhead. Also, fuses are generally not available in as high ratings as links, and they tend to blow quicker and are more vulnerable to corrosion. I guess the main reason the manufacturers used them is that they'd be cheaper than fuses w/ holders, but I highly recommend you protect the wiring (close to the starter).

Re: Starter solenoid and HEI current draw
 

For now I have a 30A fused relay sending current to the starter solenoid when the key is turned to start. I'm not sure how many amps the starter solenoid can handle but I'm guessing 30A should be adequate unless someone says otherwise.

The starter is wired straight to the battery. I see a lot of cars with this setup from the factory.

If I should put a fusible link between the battery and the starter please let me know.

Re: Starter solenoid and HEI current draw
 

It's impractical to fuse battery-starter. It would require a 400A fuse and would lead to a lower cranking voltage. The fusible links in question are placed in the wires coming off the starter before going into the car.
It's better to have the solenoid current coming straight from the battery through a relay like you have done, rather than having it like original through the ignition key. A 30A fuse may hold for a while but will eventually fail.
It's the solenoid that draws the current in question, and the fuse that may or may not handle that current, depending on the amount of time it flows.
An ordinary slow fuse can handle twice its rated current for 20 seconds before it blows. Repeated shorter overcurrents will also eventually wear it out.

Re: Starter solenoid and HEI current draw
 

If 30A isn't adequate, how much should it be then?

Re: Starter solenoid and HEI current draw
 

Ok there is NO fuse going to starter to battery for one thing it would need to be like 100 amps or better. B/c starter draws quite a bit and i know if you keep turning the starter it will draw up to 100 or more. Just go to the parts store buy you a cable with top post and connect it. Trust me you don't want a fuse. Its totally fine without one it.

Re: Starter solenoid and HEI current draw
 

That's what I have now. I was asking about the fuse for the starter solenoid.

Re: Starter solenoid and HEI current draw
 

I would believe the one for the starter selenoid would be 30 amps like you said. B/c it has like 16 or 12 ga wire on that. It would be any more than 50amps i know of. I almost betting it would be 30amps. I am pretty sure. i thought you were talking about the battery to starter boy lol. that would givin you grief.

Re: Starter solenoid and HEI current draw
 

The start signal wire (from the ignition switch to the start terminal) draws less than 15 amps in a good condition starter.
If a 30 amp "would eventually fail" for this duty, I'd have a whole lot more remote starters coming back, since they can be fused as low as 20 amps. ;)

I'm not a fan of fusable links either, and are rarely seen on newer cars as well, with the underhood fuse boxes, that can contain fuses upwards of 80A in some cases. I've seen a few imports that had 120A fuses for the alternator.

Re: Starter solenoid and HEI current draw
 

Thanks for clearing that up. I'm running a 10 gauge wire to the starter solenoid with a 30A fuse.

A lot of cars come from the factory like this so I'm guessing I'll be ok.

Thanks again for all the help. I think I have all the answers I originally asked for. You all have been a great help.

Re: Starter solenoid and HEI current draw
 

No problem glad that i could help. have fun and keep posted if it worked.

Re: Starter solenoid and HEI current draw
 

Thanks for all the help so far.

I think right now I'm going to run 0/1 gauge from the battery to a 300A fuse, to the starter, then to the alternator.

I also have another 0/1 gauge from the battery to another 300A fuse and then to a power distribution block. The HEI and starter solenoid is each getting 30A fuses.

Right now I have a 2 gauge one wire from alternator to starter and battery. It's unfused. I'm not sure I'm comfortable with this setup so that's why I'm going to 0/1 gauge and 300A fuse.

Re: Starter solenoid and HEI current draw
 

If I get this right you're going to feed the chassis electrical with 1/0 wire and a 300 amp fuse. The 300 amp fuse is virtually useless as any of the wiring downstream will melt before it burns that fuse out. Even the 1/0 wire is rated 285 amps max so it would probably hold just as long as the fuse. The idea behind fuses and links is that they are the weakest part of the system so they will go first when overloaded. Protecting the wiring and components. The factory feeds the chassis electrical with #8 protected by #12 fusible links. Fusible links are used instead of fuses here because they can withstand a little current overdraw without failing-they can take a little heat but will be the first to go if something shortd to ground. The starter battery cable never gets fused so it can draw maximum battery power.
Anyway, that's how I understand it. I could be wrong but I thought I'd share my opinion.

Re: Starter solenoid and HEI current draw
 

Thanks for the comment. I'm still designing the circuit so nothing is final yet.

I understand a 1/0 AWG wire is rated for 285A for chassis wiring. I may actually use a 250A fuse instead of a 300A.

Each component has its own 5-30A fuse so I anticipate the main feed wire will never reach 300A, but the 300A fuse is there in case the main wire shorts to ground.

I understand that the starter needs to draw as much current as possible, but I'm a little uncomfortable with a 2 AWG unfused wire connecting the starter straight to the battery. Should the starter fail or the wire gets short for whatever reason, that wire has no protection.

For now I have it like this:

(+) battery terminal - very short 1/0 AWG wire - 300A fuse - 1/0 AWG wire - 300A battery disconnect switch - 1/0 AWG wire - distribution block

The distribution block branches off to the starter and one-wire alternator with another 1/0 AWG wire. The distribution block also feeds power to the accessories with a 1/0 AWG wire.

Of course each wire that draws current from the accessories feed wire has its own fuse and is as short as possible before connecting to the fuse.

Any additional comment is welcome.