Fuel rack solenoid

[Jens]

I have a Synchro-Start mdel 1753 solenoid that I use for fuel rack shutdown when an error occures.

http://pj-power.com/page/17nef/GAC_Synchro-Start.html?gclid=CLedqOihtJ4CFQgtawodThFGmg
The solenoid looks like the one on the right side top pickure in the link above.

As you can imagine, there is a plunger that is in the solenoid. It gets pushed out by a spring that is underneath the rubber boot you see in the picture. Problem is, the rubber boot is the only thing that holds the plunger inside the solenoid. There is a small lip on the solenoid end of the boot which seats in a groove in the solenoid boddy. Unfortunately, this arrangement is insufficient to retainn the plunger. What I did was to take a band clamp and placed it around the boot where the boot connects to the solenoid body.

This worked great for a while until today
The rubber boot split at the solenoid and the plunger is no longer retained when the solenoid is switched off.

I wonder what other people do to retain the plunger. Is your solenoid plunger retained by more than the rubber boot ? If so, I would be interested in make and model of your solenoid. If you use an external device to retain the plunger, is it just a bracket to limit plunger travel ? Thoughts ?

Jens

[dubbleUJay]

Jens, I cant help you with your question, but I can say this, someone needs to devise a mechanism for these non-SOM Lister & 'roids to lift the exhaust valve and close the rack with one solenoid like on the original SOM's.
I was very lucky to find a 2ndhand one for a Start-o-Matic, but I would've made one if I didn't!
You've got a twin IIRC, but the same mechanics could just be extended
It should not be so difficult and I'll gladly give dimensions of the original if someone wants it. The manual valve lifting lever (Decompression) is already there for one mounting point and there is just one more place were the original solenoid on the  6/1 was mounted. Mine didn't have the hole, so I just tapped one for a 1/2" bolt.

Just of the top of my head, a piece of angle iron for a base, a 10mm round-bar or rod, mounted in 2x bushes onto the angle-iron, 3 levers coming off the round-bar, 1 lifting the valve, 1 pushing the rack closed and the last one connected to the solenoid to operate it

I'm going to run out of 2cent pieces. 

[BruceM]

Yes, I have the pneumatic valve lifter and rack compressor, easy for me as my Listeroid is dual use generator and compressor. 

A simpler electronic solution than a massive SOM solenoid type mechanism would be to use an RC servo for each. As in the SOM, the valve doesn't have to be lifted, just a spring loaded spacer or swing the manual lifter lever with a detachable arm so that manual operations are preserved. That can use a cheap servo. ($18). The rack takes 10 lbs of force to close at full stop, as I recall,  but that an be met with a giant scale servo ($40) with the proper linkage to maximize force at the end of travel.  To drive the two servos, I could throw a few lines of code for a Picaxe 08M (8 pin) chip ($3).  If someone wants it.   Then you'd just have one digital input which would control the servo position...open rack and release valve, or close rack and open valve.

[mobile_bob]

the syncrostart solenoids should be mounted in such a manner as to limit the free travel of the plunger
to where it cannot fall out or put undue stress on the boot,

also as you are probably aware it is imperative that you set the solenoid up so that it can fully retract
as this is what switches out the pullin winding over to the hold in winding.

if it cannot switch over from pullin to hold in the pullin coil will burn out in pretty short order, rendering the solenoid
useless.

bob g