Ford Solenoid Hot Start installation instructions, Mark Henry's method Options

[ndfrigi]

thank you for sharing!

[jim_hoyland]

Great write up- Admins, please add this to the Classics
One question: how is the Ford solenoid different from using a 50 amp relay. Many hot-start kits and threads in The Garage use the smaller relay. Just curious as to the pros and cons... (IMG:style_emoticons/default/smile.gif)

I don't want an argument as to which is better but this is my logic:

1/ I've been doing this forever, not about to change. Before me guy's like Gene Berg have been doing it since the 60's, so this has been a mod done for over 50 years.

2/ The Ford solenoid is waterproof, at least damn water resistant, the SPST relay is not at all. So you must mount the bosch horn relay in the engine bay, run wires through the grommet, tap into a power source, use a fuse, drill a mounting hole and cut the factory wire or at least make an extension/adaptor.

3/ the SPST relay may be 30-50amp which should be enough on paper, but it still has very small contacts. The Ford solenoid must be rated for at least 500 cranking amps, likely much more.

4/ I've personally only had one failure, one that was so badly corroded after 8 winters that the bracket/bottom rusted right off at the rivets and the solenoid literally spilled it's guts in my hand when I took it off.
I've replaced several perfectly good looking SPST relays with a ford unit.

Thanks for that clarification; makes good sense. Is there a part # for the type of solenoid you used above ? I'M going o switch out my "horn relay" for the Ford relay as y let your excellent write up

[SKL1]

Thanks much Mark- on my way out to the garage...

[Mark Henry]

I added a point about running the wire, make sure it doesn't touch the starter, as it could eventually rub through the plastic covering.
I've never seen it happen, but better to be safe than sorry.

[stinkindiesel]

Thanks Mark!

I mounted mine using a couple of hose clamps around the solenoid, but I like your method better.

Gary

[GeorgeRud]

I wonder if there's another design that would allow the solenoid to mount utilizing both ears rather than one? As the one side is at a constant +12 volts, I'd be concerned about vibration eventually causing the solenoid mount to crack and create a mother of a short if that terminal contacted the grounded metal. Perhaps a bracket using two of the transmission to engine mounting bolts would make a sturdier, vibration resistant design. Yes, I am a belt and suspenders type of guy, but have witnessed what happens when a battery positive terminal touches the metal of the body firsthand.

Still, great write up on the wiring for the solenoid.

[914GT]

A few more things to consider...
I like to use wire with a high-temp insulation around the engine. Some of the primary wire from the local auto store has PVC insulation that can melt pretty easy so make sure it can't get too close to hot parts. I like Teflon insulation, or maybe put heat shrink tubing over the full length for extra insulation.

I don't trust crimp terminals for anything high current or vibration. For some extra reliability you can wick some solder into the terminals.

The protective caps on the big terminals is really a good idea not just in case the relay came loose. An exposed terminal to the battery can be dangerous if you accidently got a wrench or screwdriver across it. I know someone who got his watch band on a starter solenoid terminal and it took a long time for the severe burn on his wrist to heal up. Of course he shouldn't have had a watch on in the first place.

[EdwardBlume]

Nice work Mark! Classic for sure.

[HalfMoon]

Genius level hack.
Good on ya Mark!
(IMG:style_emoticons/default/beerchug.gif)

[Mark Henry]

I wonder if there's another design that would allow the solenoid to mount utilizing both ears rather than one? As the one side is at a constant +12 volts, I'd be concerned about vibration eventually causing the solenoid mount to crack and create a mother of a short if that terminal contacted the grounded metal. Perhaps a bracket using two of the transmission to engine mounting bolts would make a sturdier, vibration resistant design. Yes, I am a belt and suspenders type of guy, but have witnessed what happens when a battery positive terminal touches the metal of the body firsthand.

Still, great write up on the wiring for the solenoid.

I've never had an issue and one car I did, a summer DD, has had the same repair for close to 25 years without being touched. If you're worried about the nut coming loose just use some red loctite on it.
Same with the wires, since the solenoid is attached to the tranny it doesn't see a huge amount of vibration. If the solenoid was screwed to the body then I'd worry about the connectors and vibration.
I've also never seen heat as an issue as well.

Not my first rodeo, I've done this mod countless times since around 1990.

[Harpo]

Nicely done Mark

[Mark Henry]

Thanks everyone (IMG:style_emoticons/default/bye1.gif)

Just to calm some peeps fears I did some housekeeping on my install and made it even better. I shaped the main battery cable so it runs right beside my wires, then I zip-tied the whole bundle together.
So that's a 3 gauge and two 10 gauge wires tied together, the thing is almost like a solid pipe. If the nut holding the solenoid on was to come loose the solenoid still isn't going anywhere.
Short of something catastrophic, like an axle failure, I'd say it's now bulletproof.

[Mark Henry]

I know I've said I dont like to cut factory wires, but this is all part of my custom /6 conversion harness.
This is the custom end of the engine harness I made from an salvaged main harness and pins from an old relay board. My /6 engine is total plug and play with about 6 connectors and the relay board has been deleted.
The harness stays on the engine for R&R.

[SKL1]

Finished installing the new "Ford" part- got it from Amazon for $20 shipped prime. A little different than the one above with only one small terminal- works great. Car cranked right over.

Thx Mark.

[GeorgeRud]

Now that looks very sturdy and it's a beautiful write up.

[Rob-O]

Great write up. And to think, the money you spend on the solenoid will prevent you from having to purchase six Chinese made ignition switches over the next year and a half...

It's a win-win.

[Mark Henry]

I added a link to this thread in my signature. (IMG:style_emoticons/default/smile.gif)

[jkb944t]

Mark--very impressive write up/ conversion. Somehow I missed this earlier so thanks for sharing.

Jeff B

[11tenths]

I bet the Cap'n would approve, but Slits would still bitch about something...

I miss them a lot, but your posts go a long way towards filling the gap they left.

Nice job (IMG:style_emoticons/default/beerchug.gif)

Cheers- Harry

[moorepower]

The Ford solenoid is a great idea, and works with most applications. I would soldier the joints to keep from corroding and assure a long term connection. I worked on Brown trucks for 25 years so I can attest to the solenoid, but also the upgrade to solder as well. I really like the liquid electrical tape over the studs and any wire exposed to the elements as well.