• From: Baltimore, MD
  • Registered: 2010-05-20
  • Posts: 1,745

Topic: Junkyard source for solenoids

Anyone have any idea what sort of cars I'd want to look at to grab an easily accessible (i.e. up top, not buried down next to the starter motor) starter solenoid?

The later the model, the better - my local yards aren't exactly brimming in classic American Iron (or really even much in the way of 80's garbage) or I'd just go scout it out the hard way.

Or maybe one of you fine gentlemen has a castoff from your parts car that you'll let go for peanuts?

Backstory and reasoning follows:

So I've had a very nice winch fall into my lap and I'm working out how to mount it to my truck. The cutoff switch is borked (the switch bit is missing) so I have to fix that. This led to some other modification decisions (pull the control box off, stash it under the hood, replace the cutoff switch with a remote-triggered solenoid, toss the remote control plug behind the grille, run control lines into the cab...)

All of this is easy, except that solenoid in place of the cutoff switch - I don't have any of those lying around. The natural course of action here would be a starter solenoid. I could drop $11 at Summit Racing and get this: http://www.summitracing.com/parts/AAF-ALL76203/ or $20 on any random one at RockAuto, but I don't think that's within the spirit of this truck build (cheap and halfass at all times) so it's off to the junkyard.

Driver, Pit Monkey, Rod Buster and Engine Fire Starter
Team FinalGear
  • From: Rockville, MD
  • Registered: 2010-12-15
  • Posts: 1,155

Re: Junkyard source for solenoids

Try motorcycles. Most junkyards have a few bikes sitting upfront, and all the ones I've seen have solenoids sitting somewhere near the battery, separate from the starter. Just trace the big red wire coming out of the motor to wherever it's going to, and you'll see the solenoid itself.

K Car Stalker
  • sergio
  • Lemons Staff Stalker
  • Offline
  • Registered: 2009-04-30
  • Posts: 1,185

Re: Junkyard source for solenoids

Good answer! Most bikes have them under the seat or behind a side cover.
What about an old Ford soleniod? Those are on the fender.

  • From: Augusta, GA
  • Registered: 2009-11-11
  • Posts: 33

Re: Junkyard source for solenoids

Not sure what size winch you've obtained, but I would stay away from automotive starter solenoids.  I built a bank of them for my 8000 lb winch and was surprised how quickly they failed.  It wasn't the contacts that failed, it was the coil that got hot and melted.  Starter solenoids are designed for high currents but relatively short duration use.  A contactor, on the other hand, is designed with a 100% duty cycle in mind. If the usage time between cool off's is brief, they should last a little while.

BTW - Crown Vic's, LTD's, etc.. are an easy source.  Or let me know and I'll send you half a dozen for shipping.

Let's make better mistakes tomorrow
  • From: Baltimore, MD
  • Registered: 2010-05-20
  • Posts: 1,745

Re: Junkyard source for solenoids

It's an older Mile Marker somewhere in the 8-12klb range (no identifying markings to figure out the exact weight capacity, and I'm not exactly going to pull it apart to figure out the gear ratio)

So I guess the starter solenoid is out. Where can I steal a contactor?


(I also have a HUGE 10a/240vAC-rated solid state relay that would probably do the job, but I'm trying to save it for a rainy day)

Driver, Pit Monkey, Rod Buster and Engine Fire Starter
Team FinalGear

6 Reply by pastafarian (edited by pastafarian 2011-06-21 06:50 PM)

  • From: Augusta, GA
  • Registered: 2009-11-11
  • Posts: 33

Re: Junkyard source for solenoids

I've found some in the junk yard on vans with wheelchair lifts.  Most 12 VDC powered hydraulic equipment would have something suitable.  I'd look on ebay as well for used or surplus equipment.  You can always use the started solenoids, just keep a spare or two handy.

Your SSR is likely 240 AC rated on the trigger as well as the load side and would be very happy with 12V DC and the 10A rating would only hold the motor with no load.  A 8K series wound winch near stall will pull 300+ Amps.  One problem with SSR's is the heat production related to the load.  They must be able to dissipate the heat or will quickly fail.

I just re-read your initial post and I may have misunderstood the need.  Is this for the remote or the winch motor itself?

Let's make better mistakes tomorrow
  • From: Baltimore, MD
  • Registered: 2010-05-20
  • Posts: 1,745

Re: Junkyard source for solenoids

Winch motor itself. Or, rather, a power cutoff to the solenoids (I told you it was old) that control the motor.

Frankly, I'd just skip the cutoff altogether if it weren't for the unpleasant possibility that one of the control solenoids would burn out and fail engaged.

Driver, Pit Monkey, Rod Buster and Engine Fire Starter
Team FinalGear
  • From: Baltimore, MD
  • Registered: 2010-05-20
  • Posts: 1,745

Re: Junkyard source for solenoids

http://pic.phyrefile.com/e/ey/eyemwing/2011/06/21/rapidprototyping.png

Here's the proposed circuit.

The component under discussion is "CUTOFF". In the original circuit, CUTOFF is  racecar-type killswitch (but the knob is MIA) and the cab controls are not present.

Driver, Pit Monkey, Rod Buster and Engine Fire Starter
Team FinalGear
  • From: Augusta, GA
  • Registered: 2009-11-11
  • Posts: 33

Re: Junkyard source for solenoids

Ok, so this must be a permanent magnet motor with SPDT type contactors, assuming there are only two wires from the motor. If there are 4 wires or posts on the motor then it's series wound and will require 4 contactors since the field and armature both require power.  The item you are in need of should be sized equal to or greater than the two motor contactors pictured.   The "cutoff relay" isn't really needed, a standalone switch would be just fine (only has to carry the current draw of a coil).  If you have any questions feel free to give a call.

Let's make better mistakes tomorrow
  • From: Baltimore, MD
  • Registered: 2010-05-20
  • Posts: 1,745

Re: Junkyard source for solenoids

pastafarian wrote:

Ok, so this must be a permanent magnet motor with SPDT type contactors, assuming there are only two wires from the motor. If there are 4 wires or posts on the motor then it's series wound and will require 4 contactors since the field and armature both require power.  The item you are in need of should be sized equal to or greater than the two motor contactors pictured.   The "cutoff relay" isn't really needed, a standalone switch would be just fine (only has to carry the current draw of a coil).  If you have any questions feel free to give a call.

Yeah, the relay isn't necessary, but the switch circuit I'm hijacking already has one.

The motor is, according to specs, series-wound - I presume the additional posts are handled inside the waterproof enclosure - I only have two posts externally.

Getting ratings or detailed specs on the existing control solenoids/contactors/whatever doesn't seem to be possible - the only markings on them other than "12V" are very much Chinese.

The winch manufacturer lists a relatively low duty cycle - I'm considering modifying it so the cutoff is only closed when both the cutoff switch AND a control line are closed. That'll (probably) save the cutoff coil from overheating at idle, and the whole winch assembly's duty cycle is 10% anyway.

Driver, Pit Monkey, Rod Buster and Engine Fire Starter
Team FinalGear