Valve pin on Marauder is stuck flush with valve body but no leak?

[HunterWhite]

As far as the stem shooting out, IMHO there isn't enough surface area to provide enough push to push it out.

The stem is 0.125", a pellet is 0.177".
I wouldn't spend too much time staring down into the tube.

Hunter

[SpeedyBB]

Okay, it's done. Picture attached, old is on the bottom, new is on the top. It was exactly what was guessed. Glad I got a new spring too because look at the amount of rust on the old one. Gun always gets pumped indoors with air conditioning but I guess Ohio humidity can still be too much. I had to re-use an old o-ring because two got torn on the gauge port hole when re-assembling, not happy about that, whether it leaks or not will be known soon enough. I used a dremel and carefully de-burred the inside of the gauge port hole, after that the o-rings slid right over it, wish I had known to do that from the start. How the factory got them in there without the same thing happening is beyond me. I used a little Trident 100% silicone grease on the o-rings when assembling.
Now here's the mystery, I'm pretty sure the gun is shooting harder now, and I didn't change the tune. I did some quick night testing with a flashlight aimed at the target, and I thought it sounded louder (I didn't forget to put the de-pinger back in). The amount of shots brought the pressure down more than it should have. Very strange. If this is the case I will need to re-tune I guess. I'll get the chrony out with it tomorrow if the weather is good and I'm feeling it.
I have covid, right now, confirmed. Six days in of symptoms. Pumping the gun up from nothing to 3,000 was tough, and I needed to take more and longer breaks than I otherwise would have. Also went to show just how much air is crammed into that tube to get it to 3,000 psi, it's pretty neat.

EDIT
Come to think about it, the gauge port o-rings shouldn't matter much. So I hope the one on the valve is a new one. Cannot remember.

[Motorhead]

YUP ... poppet stem driven right threw the poppet head !

[SpeedyBB]

YUP ... poppet stem driven right threw the poppet head !

Yep. Maybe all the moisture rotted it? But I am really wondering if it had a small tear for a really long time because I'm pretty sure the gun is shooting harder now. Either that or the new valve spring is weaker, but I doubt that.

Also, I re-re-thought it over, the gauge port o-rings ARE important as to stop air from leaking out of the gauge port hole, duh. Hasn't leaked yet in hours, so it's a good sign so far.

[Ribbonstone]

 Cool....sheared the top part of the poppet off...nothing it could have done but end up with the valve stem shaft about even with the face of the valve.

Usually they'll slow leak down the exposed pin shaft when that happens.....and it does happen.

As much as we think of Delrin as non-reactive, it really isn't immune from hardening...and a right angle (like the "step" in the valve poppet from large to small) is a stress collector.

[triggertreat]

I have hit those poppets with a heavy hammer tune as hard as any other power tuner has pushing a little over 75 FPE with my .25 Synrod.  I have never had one to do me that way.  So yes, that one may of had a flaw in it, or became overly hot while in the sunshine/heat.

[FuzzyGrub]

Thx for the follow up post.  Lots of rust on that poppet stem, as well as the spring.  How was the inside of the tube?  Near the front gauge block  o-ring is a typical problem area with high moisture conditions.

[SpeedyBB]

Tube seemed mostly fine, not perfect. Nothing that's alarming me, just signs that eventually the tube will need replaced. I saw orange so rust wanted to start somewhere, likely where the depinger was sitting. After pushing some rags through everything looked really polished and shiny except for one very small spot, there was one really little smudge (smaller than a dime) that might have been early surface rust starting where the depinger was. I didn't see any rust rings where the o-rings were, there was a tiny bit of orange on the gauge port o-ring though, but I think that was just collected as it pushed past that smudge left by the depinger since it was not around the o-ring but in one small spot like was seen on the depinger. There was no pitting as far as a flashlight could tell me.
There was a lot of filth in the tube, picture attached. There is the depinger after coming out which collected a lot of the filth, that congealed clearish white stuff that looks like salt was soft to the touch and could be broken apart in your fingers. Maybe it's congealed silicone oil that gets in there when I'm pumping? I'm not sure what it was. And you can see a little orange on it too. All in all I think the tube is fine for now, if it needs replaced down the road it's easy enough to do. It would be an excuse to switch to an aluminum tube anyway, taking more than a pound off the gun.
By the way, as for it getting louder, I took a look at the dowel I used to measure how far to push the depinger, and it had another mark on it from a previous project from who knows when that I accidentally used. Took the fill valve off and sure enough the depinger was not pushed in far enough, it had like four inches to go. The factory pretty much had the depinger sitting directly in the middle of the tube so that's about what I did plus a little more to hopefully clear that smudge. I'm about to test the gun to with the chrony to check the tune. Hoping it didn't somehow change.

[Ribbonstone]

tiggerheat:

Add the word "yet" and you're good.



Gauge blocks:

realize that they are open to the outside air between the two O-rings on the gauge block (through the tube hole for the gauge)….what happens there is unpressurized and not the fault of the fill air.


The inside of the valve (where that valve stem retrun spring lives) will see every bit of fill moisture pass though/collect on the spring...less moisture is going to take longer to rust it,but it will get rusted...it'swhere the drop in pressure/cooling/condensation would want to deposit it.

If you had not already put it all together, would tell you to "wax" (thin coat) everything inside with Silicone grease.

[SpeedyBB]

tiggerheat:

Add the word "yet" and you're good.



Gauge blocks:

realize that they are open to the outside air between the two O-rings on the gauge block (through the tube hole for the gauge)….what happens there is unpressurized and not the fault of the fill air.


The inside of the valve (where that valve stem retrun spring lives) will see every bit of fill moisture pass though/collect on the spring...less moisture is going to take longer to rust it,but it will get rusted...it'swhere the drop in pressure/cooling/condensation would want to deposit it.

If you had not already put it all together, would tell you to "wax" (thin coat) everything inside with Silicone grease.

Using the gauge port with old o-rings I used the trident grease and pushed it through the tube a couple of times, adding grease each time. How well that will work I don't know. There is definitely a thin layer of grease though. The inside of the valve and valve stem just got a thin layer of silicone oil though. Valve is brass so it'll be fine. The spring and stem will inevitably rust again though.

[AlanMcD]

Glad it is fixed.  I find two things amazing about that condition: 1) that the gun still held air like that at 2900 psi, and 2) that the stem was not pushed back down flush over time, as at 2900 psi there was about 35 pounds of pressure on that stem.

[SpeedyBB]

To me, what I could tell, it got pushed flush over three shots. So it did hold for a little bit.
And puzzling but I do have a 40 fps increase. I am going to leave it for now, although I hope that the hardcast crosman pellets don't foul my barrel at 880-890 fps. I just got a couple sub .25" groups at 25 yards and some shot some earplugs at 50 so it can still shoot straight at this speed.

[triggertreat]

Glad you are back in business!

I use a 3/4" wood dowel to work the HP tube.  One end has a hole drilled in it to cover over the valve stem when installing/removing it.  I put a rag or paper towel over the rod to clean out the tube.  I lube the entire tube with silicon grease afterwards the same way, twisting as I go for more cleaning/lubing power.  I have never seen any rust inside my two.  I hand pumped for a couple of years with a Benji pump with no kind of filters, but did that indoors in drier air, and was mindful of heat buildup and didn't push it.  I never trashed an O-ring in the hand pump either.  I think the silicon lined reservoir had something to do with no rust inside, or I may have just been lucky.  Either way, the inner components sure do slide in and out easily.