Positive connection under hood
 

With the battery in the trunk?

What are you guys doing to hook up a timing light , or get 12V to test equipment,

Thinking someone may have a more creative solution than my idea of using long booster cables laying on the ground to bring battery connections to the front on the car. Anyone use the + feed on the alternator or is that a bad idea?

Sorry if these are amateur questions.

How do you have your trunk mounted battery connected to your starter? Something like the below power distribution block can be used.

https://www.summitracing.com/parts/sum-900182

Run power from the battery + cable at your starter to the power block mounted wherever you need it. You can grab power for your test equipment there.

Once I accidentally got the power cable to my timing light cut by the fan I started to use the main hot on the back of the Alt.

My firebird has a power stud location at the passenger side radiator support. But I could also pick up power at the Ford Solenoid

probably should add a ford style starter solenoid in the engine bay. thats where i hook my light to and it will help your starter and give you a distribuion point for other voltage requirements

B+ feed on the alternator for me.

K

This. I have a timing light that runs off 2 D batteries but the Ford style solenoid is a good idea for several reasons as mentioned.

If you have a Ford solenoid on the fender like you should, right there grab it right on the Ford Solenoid.
AND your solenoid on the starter itself will last forever.

I normally use a battery starter pack to power the timing light.

The "Ford solenoid" on the fender doesn't work with typical permanent-magnet gear reduction (PMGR) starters. The starter doesn't disengage cleanly, so they tend to grind the flywheel and starter drive gear every time the key is released.

I do like them when used with the older-design, direct drive electromagnet starters.

The "Ford solenoid" on the fender doesn't change the way the solenoid on the starter works, it just supplies more voltage to it. They'll still wear, and they'll still burn the copper disc and contacts inside the solenoid.

Thanks guys, I think both the Ford solenoid and power post are great ideas and I will pick one or the other as a future small project.
I also appreciate the two proven quick solutions of a portable battery pack or the main + on the back of the alternator as I’d like to check the timing and adjust the carb with a tack under the hood.

Here's what I did:
 

Mounted the Ford starter relay on the firewall, near to where the necessary circuit wiring is for convenience. The plexi box is to prevent a problem if a wrench or something falls off the cowling onto the battery connections.

George

Nope, it does in fact help the solenoid on the starter last longer. Why ? Because the Ford solenoid takes the initial high amp hit. The initial hit is what burns/wears on a solenoids contacts.
It might be milliseconds but the Ford switch gets it first, saves the one on the starter. The first high amp big draw does not take place on the starters solenoid, its already happened on the firewall.
They work fine "as is" with a Summit/Denso gear reduction starter. I have had this setup since the 90s and it works flawlessly. Same ole starter drive.
The starter does in fact disengage cleanly and does not grind my ring gear ever. I have never replaced one on a Pontiac from damage.
And I am one of those guys who starts and shuts off his engine moving up in the lanes. I don.t want a hot engine by the time I get to the line.

For whatever reason you seem to like to "correct" me a lot.
Well, not only does the Ford deal work great, no damage. It does NOT supply more voltage, its the same. It supplies more potential current/amps to the starter itself.

I've always used the alternator positive terminal and run the timing cable through the hood spring so not to have the cable cut the fan blade.

Another back of alternator

Alternator

Not possible.

Aside from adding a minuscule amount of resistance which theoretically might soften the "high amperage hit", there's very little current flow (amperage) through the Ford solenoid contacts until the starter solenoid high-amperage contacts close. The starter solenoid is seeing exactly the same conditions as it did before (with one exception, later.) The starter solenoid is still engaging with battery voltage on one copper contact, the disc bridges the gap to the second (motor) contact, which is essentially a dead-short since the motor isn't turning yet.

Battery voltage into a dead short is going to be (for an instant) a high-amperage hit, just like it would be without the Ford solenoid on the fender. The contacts on the Ford solenoid are already closed before the high-amperage starter draw flows through them, while the starter solenoid closes "live", power on one contact, ground on the other. The only current flowing through the Ford solenoid contacts as they close, would be the low-amperage of the starter solenoid windings. Only after the starter solenoid builds magnetism, pulling the plunger, and snapping the copper disc into contact with it's mating copper lugs, does the full starter motor current flow though the Ford solenoid contacts.

What does the Ford solenoid do? The wiring layout with the Ford solenoid provides a higher-voltage, increased amperage power supply to the starter solenoid WINDINGS, usually eliminating the "failure to crank when hot" problem with the old Delco direct-drive starter motors. The vehicle wire harness, in particular the circuit connected to the "S" terminal of the starter solenoid via the purple wire becomes frail (high resistance, corroded wires, poor connections) which means the solenoid windings get poor power and therefore a weakened magnetic pull on the starter motor plunger. Since the purple wire is no longer connected to the starter solenoid, a short, high-capacity copper link connects the heavy battery cable to the "S" terminal, assuring that the solenoid windings have all the power they can handle. I've seen those links as a solid piece of copper barstock, and also as a very short copper multistrand wire. Either way, internal resistance of that link is as close to zero as my equipment can measure.

As a side benefit, the heavy battery cable connected to the starter solenoid is no longer electrically "hot" 24/7/365, somewhat reducing the chances of short-circuiting due to insulation failure, and setting the car on fire.

So, if there's a reason for the Ford solenoid helping to preserve the starter solenoid, it would be because the improved power via the short link to the "S" terminal causes the solenoid to engage more quickly, more forcefully. I suppose this could improve the service life of the copper disc and the contacts...but I think we're back to theoretical improvement not "real" improvements.

The "Ford Solenoid" does NOT work well on a GM/Delco PG260 PMGR starter. The starter is slow to disengage, grinds the flywheel.

So...I guess...it depends on the PMGR starter being used with the Ford solenoid. I thought the failure to release cleanly was universal with PMGR starters, and apparently I was wrong.


Not that I'd noticed. At least, not you in particular. But if you say so...


As said, compared to failing OEM wiring/connections, the wiring system used with the Ford solenoid can supply more voltage/amperage (power) to the starter solenoid windings via the very short copper link from main battery cable terminal to the solenoid "S" terminal. Because inserting the Ford solenoid into the heavy battery cable will inevitably add some tiny amount of resistance, actual power delivered through the bigass battery cable to the starter solenoid would theoretically be reduced...but probably not enough to measure, let alone affect actual operation.

^^^^^^^^^^^^^^^^^
What he said

I have used the Ford solenoid with a factory GM starter and with a mini starter and it has always worked great for me. Never had a problem with the starter not disengaging all the way as mentioned.

I personally do not favor connecting a large battery cable to the alternator output stud. The stud is relatively small mechanically. Just my opinion.

george