[Skip Fix]

Wiring a run stand what size should I use for both of these, as well as fuse amperage. Figured more traffic here than Electrical folder

[zippy]

12Ga to HEI 14 or even 16 to starter Sol. I actually have 16ga to my starter and works well for many years.
14Ga in house wiring is good for 15A, 12ga is 20A. Car, you can get away with a lot more.
HEI only takes 3-5A when running. Starting surge can go alot more, but its brief. Say 20A.
I'd fuse at 25 for HEI

[johnta1]

The wire to start the solenoid cranking or for the ignition wire on solenoid?

[Skip Fix]

Start the solenoid cranking.

[steve25]

You also need a give gauge of wire depend on how long it is, so it’s not just current related

I have a chart I will try to dig up.

[HWYSTR455]

So this is for an engine stand? Will it be used frequently?

Gauge is one thing, but quality is probably more of a concern if the wires are going to move around a lot.

If it's used a lot, it would probably be best to go up one size on gauge, and maybe even make short breakout harnesses in case you need to make diff connections on diff engines. If you're not sure, you could always add them later, but one larger gauge will make it last longer.

You could also use wire covering, like split sleeve nylon, instead of zip ties, which prevents multiple wire runs from being flexible.

For fuses, I would have to suggest solid state breakers. Those last longer and are easily reset.

Are you using a remote start sol for the stand? That would prob be a good idea, would only need to connect a power lead that way. If stock starters are used you can jump the terminals.

There's a bunch of 'kits' out there for test stand, you can do an internet search for something like 'engine test stand wiring diagram' to help get ideas.

Some of it matters how nice you want to make it too.



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[Skip Fix]

Probably 3-4 feet at max run from the key. I have a 4 fuse fuse box I was going to use to split off for starter/ignition and gauges and a fuel pump.
https://www.summitracing.com/parts/l...xoCWZEQAvD_BwE
radiator under the gauges and front of engine to gauges,
Rear will probably go to some of the extra scattershield holes. And this one is only a one starter pocket scattershield

[steve25]

Here’s a handy guide to print off and stuff in your crimp on connector box.

[Bill Hanlon]

Similar, but more comprehensive wire size chart.

[Skip Fix]

Amp draw for solenoid and ignition coils?

[johnta1]

The wire for the solenoid I would use at least 12 gauge. What factory was I believe. Solenoid draw can be around 45 amps or more.
Coil not for sure maybe a couple amps.

[Skip Fix]

Thanks .Trying to get this useable to see if I fixed the 455 rear main leak!

[steve25]

The initial hit at closing draws between 35 to 50 amps.

This is dependent on how much voltage your battery has on hand ( good old ohms law comes into play here big time ! ) and the temperature of the starter itself, as in the higher the temperature of the solenoid coil winding then the greater the resistance there will be that the circuits available voltage and current will have to overcome.

This is why many many decades ago before the availability of gear reduction type starters we used a separate Ford type solenoid mounted like Ford did on your wheel well or firewall, and we jumped out the one on the cars starter.


Once the GM type solenoid is engaged it only takes 8 to 15 amps of current, but you need to be set up for at least 40 amps and then see if that wire gets warm in use.

[Skip Fix]

Are there any 40 amp circuits in a car fuse box?

[johnta1]

I don't think so in the fuse box.
The A/C may be a big amp draw but has separate fuse. (like by the alternator)
Headlights may have a circuit breaker maybe?
Come to think of it there might be a circuit breaker for the rear defog in the fuse box. (uses an empty spot made for it)

[HWYSTR455]

Waytek has a bunch of circuit breakers ranging from 20-150a:

Here's a 60a:

https://www.waytekwire.com/catalog/c...-surface-mount

I say use a 100a, which gives you short protection, and less chance of a trip on initial hit.

Use quality wire & terminals. Waytek has a wide selection of terminals.

For wire, use GXL:

https://www.wirebarn.com/GXL-Automot...ot_c_1202.html

For batter and starter runs, use SGT or SGX:

https://www.wirebarn.com/Battery-Cable_c_1447.html

Can use braided split loom if you choose to, this place sells by the foot:

https://kwikwire.com/products/braide...om-by-the-foot

There are other sources and can shop it.

You can mount a Ford external sol on the stand, reducing 'hot' wires going to the engine, and use less wire.

You could also mount a regulator on the stand with a fuel psi gauge.



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[Skip Fix]

Thanks for the links.

[Schurkey]

HEI doesn't draw much AVERAGE amperage, but it draws a fairly heavy instantaneous load. Note that GM uses at least 12-gauge wire to the coil-in-cap distributor, and 12-gauge to the coil, and from the coil to the ignition module on remote-coil applications.

Kinda thinking the starter solenoid "S" terminal is also 12-gauge. If the solenoid draws 40 amps, it's for such a short time that 12-gauge wire is sufficient. I think the "R" terminal is smaller-gauge, but it's been so long since I've dealt with "R"-terminal wiring that I don't remember for sure. All of this can be confirmed by the appropriate Genuine GM service manual; or by simply looking at the original wire gauge size on the car.

My "run stand" isn't fused. Now you've got me thinking...

[Dragncar]

Ford solenoid and a jumper.