Starter solenoid

[Scott Hersha]

I have a question about starter solenoids for my O-360 on my RV6. I need a new one. While removing/reinstalling my alternator feed line wire from my starter solenoid to replace my current sensor, I either cross threaded the 5/16-24 nut or just over torqued it, and stripped the threads on the brass stud on the solenoid. I can order a new one from Spruce or Vans (in stock) and it will take a few days to get here. OR - I can get one from NAPA that looks like the same thing this morning and be flying this afternoon.

From what I’ve read, the starter solenoid should be able to handle an inrush current of at least 300 amps, and should have silver contacts inside. The NAPA one is rated for 300 amps, but no indication about the silver contacts. Has anyone here had experience with automotive starter solenoids used on Lycomings?

 

[Dad's RV-10]

I have a question about starter solenoids for my O-360 on my RV6. I need a new one. While removing/reinstalling my alternator feed line wire from my starter solenoid to replace my current sensor, I either cross threaded the 5/16-24 nut or just over torqued it, and stripped the threads on the brass stud on the solenoid. I can order a new one from Spruce or Vans (in stock) and it will take a few days to get here. OR - I can get one from NAPA that looks like the same thing this morning and be flying this afternoon.

From what I’ve read, the starter solenoid should be able to handle an inrush current of at least 300 amps, and should have silver contacts inside. The NAPA one is rated for 300 amps, but no indication about the silver contacts. Has anyone here had experience with automotive starter solenoids used on Lycomings?

If you're asking about the Cole Hersee 24021 starter contactor, the one you can buy from Napa is the exact same part you'll receive from Van's.

 

[Scott Hersha]

If you're asking about the Cole Hersee 24021 starter contactor, the one you can buy from Napa is the exact same part you'll receive from Van's.

Thanks for the reply. Checking the Cole Hersee 24021, it doesn’t have silver plated contacts, same as the Echlin ST81 solenoid at NAPA (the one that is in stock at all NAPA stores near me). Copper or copper alloy contacts in both of those - so maybe it doesn’t matter. If I’m getting the exact same ones as what Vans is selling, and what I have had from the beginning, I might as well buy locally today.

edit: The Cole Hersee looks better than the Echlin but not in stock, so I ordered it from NAPA, to be delivered on Thursday (2 days) - not bad.

 

[bjdecker]

Don’t overthink this — or over buy. Cole Hersee / Littelfuse 24021 is just fine for the task at hand.

 

[lr172]

I have a question about starter solenoids for my O-360 on my RV6. I need a new one. While removing/reinstalling my alternator feed line wire from my starter solenoid to replace my current sensor, I either cross threaded the 5/16-24 nut or just over torqued it, and stripped the threads on the brass stud on the solenoid. I can order a new one from Spruce or Vans (in stock) and it will take a few days to get here. OR - I can get one from NAPA that looks like the same thing this morning and be flying this afternoon.

From what I’ve read, the starter solenoid should be able to handle an inrush current of at least 300 amps, and should have silver contacts inside. The NAPA one is rated for 300 amps, but no indication about the silver contacts. Has anyone here had experience with automotive starter solenoids used on Lycomings?

Most starter solenoids have copper contacts. Silver would be nice, but no one makes them that way. These handle the current just fine, they just suffer from pitting over time from the break portion.

 

[RWoodard]

They’re so inexpensive that I keep a starter contactor and a master contactor as spares on my shelf. Same thing with an extra start capacitor for my central air unit for my house, fwiw.

 

[bjdecker]

Most starter solenoids have copper contacts. Silver would be nice, but no one makes them that way. These handle the current just fine, they just suffer from pitting over time from the break portion.

+1 ^^ Correct. ^^

Mitigate the pitting with the use of Suppression Diodes or TVS diodes (aka "Snapjacks") to clamp the reverse current to < 20V or so.

 

[walkman]

Most starter solenoids have copper contacts. Silver would be nice, but no one makes them that way. These handle the current just fine, they just suffer from pitting over time from the break portion.

you might find a marine one, but unnecessary imho. been running with the same napa one for 15 years

 

[bjdecker]

you might find a marine one, but unnecessary imho. been running with the same napa one for 15 years

There's a whole cult bunch of folks who like the Blue Sea Systems continuous and intermittent relays. They have good reliability and the cost is commensurate with that.

 

[inktomi]

I'm going to be using a Gigvac GV21 contactor - https://www.mouser.com/ProductDetail/682-GV211BAX

Has the flyback diode internal. Gas sealed, can be installed in any orientation. Very low coil current. They're made for EVs and that sort of thing.

 

[Ruready]

I carry a spare continuous duty that way you can use it for the starter or the master
https://www.napaonline.com/en/p/TWD24213BX

 

[bjdecker]

I carry a spare continuous duty that way you can use it for the starter or the master
https://www.napaonline.com/en/p/TWD24213BXView attachment 121294

And there are your silver contacts -- more of a Master/Battery contactor application. The smaller terminals (10-32) are to energize the coil -- so it's different than the 24021 model.