C7 Starter Solenoid Napa Part#

[GCecchetto]

Not in the parts spread sheet and a search didn’t return any useful results, so curious if anyone has a Napa part # for the starter solenoid? My truck has a C7, not sure if the starter and solenoid are the same as 3116/3126 motors. Thanks

 

[GeneralDisorder]

The auxiliary solenoid is a Prestolite SBC-4401E-1

NSN 2920-01-361-5802

https://www.ametekswitch.com/products/solenoids-list/plastic-case-solenoid-sbc

I would clean and inspect ALL your starter, solenoid, and auxiliary solenoid connections before straight up replacing the unit. There's one wire in particular that runs from the auxiliary solenoid to the 1/2" stud on the starter and it's only a 14 AWG wire so they used a really mismatched ring terminal and it's not very strong. Mine was mostly torn in half.

 

[GCecchetto]

The auxiliary solenoid is a Prestolite SBC-4401E-1

NSN 2920-01-361-5802

https://www.ametekswitch.com/products/solenoids-list/plastic-case-solenoid-sbc

I would clean and inspect ALL your starter, solenoid, and auxiliary solenoid connections before straight up replacing the unit. There's one wire in particular that runs from the auxiliary solenoid to the 1/2" stud on the starter and it's only a 14 AWG wire so they used a really mismatched ring terminal and it's not very strong. Mine was mostly torn in half.

All of that wiring is new, just done before we left Maryland, but given how many things I have had to redo, that doesn't mean there isn't an issue there. The problem started just after returning home and it was something that was just a once in a while thing. Press the starter button, nothing would happen, release and repress the button or sometimes just hold it for a few seconds and it would start. it's slowly gotten worse and as of yesterday, it's pretty much a no crank situation. Just heading out to do some testing with my multimeter and see if the solenoid can be changed without removing the starter. Also the small solenoid, which I believe is called a contactor, is not the proper military part, but rather something likely from napa.

 

[GCecchetto]

Okay, the contactor is bad. Shorting across it and it fires right up.

 

[GeneralDisorder]

Okay, the contactor is bad. Shorting across it and it fires right up.

Not necessarily. And probably not likely given someone obviously already encountered this problem and didn't solve it with a new one.

It could be getting insufficient current across the coil to pull it in hard and fast and make a solid connection between the high current contacts.

Contactor; Solenoid - same, same. The term "Contactor" is typically used for high current applications and is more frequently used in AC equipment. Many contactors incorporate multiple sets of contacts, under/over current protection and phase imbalance...... The manufacturer (Ametek/Prestolite) calls this a solenoid and it's rated at 100A. The military TM calls it the Auxiliary Starter Solenoid.

 

[GCecchetto]

Not necessarily. And probably not likely given someone obviously already encountered this problem and didn't solve it with a new one.

It could be getting insufficient current across the coil to pull it in hard and fast and make a solid connection between the high current contacts.

Contactor; Solenoid - same, same. The term "Contactor" is typically used for high current applications and is more frequently used in AC equipment. Many contactors incorporate multiple sets of contacts, under/over current protection and phase imbalance...... The manufacturer (Ametek/Prestolite) calls this a solenoid and it's rated at 100A. The military TM calls it the Auxiliary Starter Solenoid.

I was getting zero volts through the relay, and the click when it was triggered was pretty loud, so I was pretty sure it was engaging but bad. New part installed now and it fires right up. Now to either replace it with the proper military part and relegate this part to being an emergency spare, or maybe I'll do some searching and see if I can find a part of significantly better quality.

 

[GeneralDisorder]

I was getting zero volts through the relay, and the click when it was triggered was pretty loud, so I was pretty sure it was engaging but bad. New part installed now and it fires right up. Now to either replace it with the proper military part and relegate this part to being an emergency spare, or maybe I'll do some searching and see if I can find a part of significantly better quality.

Interesting - could definitely be a bad replacement I suppose. I would open it up and inspect.

I guess that begs the question - why was it replaced the first time and now the truck is on solenoid #3. Don't hear about many issues with the factory unit.

 

[GCecchetto]

Interesting - could definitely be a bad replacement I suppose. I would open it up and inspect.

I guess that begs the question - why was it replaced the first time and now the truck is on solenoid #3. Don't hear about many issues with the factory unit.

I don’t know for sure if there was an issue with the original. It, along with the original starter, was in the truck when I test drove it months ago and it fired right up. The guy had a whole list of stuff he was replacing to assure it was a reliable truck/ Mechanically it is, but there are some niggles to sort out for sure.

 

[GeneralDisorder]

Huh. I'm still rocking my original starter at over 15k miles and no signs of issues. I did pick up a spare new one when one popped up cheap off a surplus crate engine but haven't needed it.

 

[GCecchetto]

I don’t know for sure if there was an issue with the original. It, along with the original starter, was in the truck when I test drove it months ago and it fired right up. The guy had a whole list of stuff he was replacing to assure it was a reliable truck/ Mechanically it is, but there are some niggles to sort out for sure.

Like I say, guy had a list the “preventative maintenance” that was being done and I don’t know if it was all because he thought it needed it or not.

On the bright side, the truck runs like a mule and it seems all the big stuff is mechanically sound. Door gaskets are supposed to deliver today, so hopefully I get at least one door done after work. Supposed to get wet tomorrow and hang around a few days, so work will be limited. Just ordered a new cab lift pump tank, gasket, MWME air dryer, and exhaust brake. Mine is rusted up solid. Think I will install a pyrometer as well, since I'm running the 370 HP tune, I would like to know what my EGT's are.

 

[GCecchetto]

So, as I said, I have no idea why the original starter and auxiliary starter solenoid where changed out, but I'm pretty sure this is the cause of the failure of the replacement aux solenoid.

 

[GeneralDisorder]

Not if it worked intermittently. Turning that stud will rip the tiny coil wire off the head of the stud and render the solenoid completely NMC (non mission capable). Once you do that it never works again or makes any noises - intermittent operation while hearing it click internally means the main contacts aren't seating or are burnt. If the replacement is that cannister style you can easily pop the lid off any see for yourself what failed.

 

[GCecchetto]

Not if it worked intermittently. Turning that stud will rip the tiny coil wire off the head of the stud and render the solenoid completely NMC (non mission capable). Once you do that it never works again or makes any noises - intermittent operation while hearing it click internally means the main contacts aren't seating or are burnt. If the replacement is that cannister style you can easily pop the lid off any see for yourself what failed.

Yea, I'll get around to it eventually. I saved the failed part. The solenoid is engaged buy the small studs, so I was thinking possibly one of the larger studs partially rotated and damaged the connection but didn't completely break and it eventually gave up from the current draw through what was left of the connection.