The Trials of Clovis

The origins of Clovis are shrouded in mystery. When I entered the story Clovis was merely a handful of parts salvaged from the Spyder graveyard at Splat-1 in Knoxville. Soon with a few improvised parts Clovis was once again functioning. A functioning Spyder is a wonderful thing but I knew Clovis deserved better.

A Palmer stabilizer was added to regulate the gas supply and about an inch was taken off the back of the top tube of the body. A slot was cut in the top of the gun and a clevis pin from the hardware store replaced the link pin. Now I could get the bolt out of the gun faster than my buddy with a Piranha. Now I had a visually distinctive Spyder, but Clovis still deserved better. That’s when the journey to low pressure began.

When I refer to low pressure I actually mean low pressure/high volume. Thinking of it this way it is easy to understand the two things you have to accomplish to get the gun to work at low pressure. Lowering the pressure is as easy as sticking on a regulator such as the Palmer Stablizer. The fun part is increasing the volume. This means not only increasing the volume of the valve chamber, but also increasing the ability of the valve system and the bolt to deliver the higher volume of gas.

Conventional wisdom seems to be to go out and buy AKALMP parts or Bob Long parts and slap them on the gun add a regulator from various manufacturers, a little tuning and viola, you have a fine and dandy well functioning and low pressure Spyder. There is a reason conventional wisdom is the conventional wisdom. Conventional wisdom is what a number of people have experinced to be true, and even though I have not put a gun together this way I have no doubt that this time the conventional wisdom is true. That was not to be the story of Clovis. Clovis was going to follow a much more difficult and darker path.

Like I said lowering the pressure is the easy part, getting the gas flow up is what makes going low pressure difficult. First you need a place to store that higher volume of gas, then the valve system must be replaced or modified to flow the higher volume of gas. To get a higher volume of gas through the valve you could take two approaches, speed up the flow of the gas to get more gas through in the same amount of time or simply modify the valve so the gashas an easier path through. Using the bigger is better attitude I’m just going to try to increase the capacity of the entire valve system.

Taking inventory of the parts I had laying around, and what I would need to go low pressure I found I had a female Palmer Stabilizer. A polished bolt from a SE, a chopped up valve body from a SE, and a shaved valve pin of unknown origins. The valve and pin resembles the graphics to the left and right. The valve body was hogged out as much as possible. The pin was already shaved in the middle, but some grooves were added at the head to help get enough gas to the hammer to cock the gun. The bolt was simply a SE bolt with the venturi piece removed, and the bore of it hogged out as much as possible. The hole on the bottom of the bolt was bored out considerably. The interesting thing about the bolt was the polishing job. To give the bolt to a nice shiny finish I had to take a lot of material off. Too much material. Now the bolt was nearly friction free as it slid up and down in the body, But it was not sealing well. A couple of swollen bottle o-rings fixed that problem. A Mad Man spring kit provided a variety of springs to play with and a borrowed low pressure volume chamber (you weren’t needing that back were you buddy) takes care of increasing the volume of the valve chamber. A 32 Degrees gauge mounted in the body was a nice finishing touch.

After considerable tuning I had a fine low pressure, 300psi, Spyder, well reasonably fine. Sometimes the gun would only cock when a ball was fired, and I had to use such a stiff main spring, that the gun was kicking quite a bit, kind of negating one of the reasons to go low pressure. At some point I decided to get a little more conventional and a turbo valve replaced the modified one. I kept working with the gun and using it and got it to were I was pretty happy with it except I was having a problem with double feeds and chopping balls. After careful examination it appeared to me that the ball detent was too far foward. So paying close attention to where the bolt rested, I drilled and tapped a hole and installed an autococker ball detent. This is one of the best modifications I believe I have made to Clovis. Of course now that I had a decent gun I couldn’t very well leave it alone.

A spare stock valve I had laying around was sacrificed to the gods of knowledge (ok I was just bored). Finding the largest drill bit that would still leave a save margin for the o-rings to seal a huge hole was drilled into the top of the valve. The front of the valve was drilled out to just a little smaller than the diameter of the cup seal. Then using variousDremel bits the interior of the valve was cleaned up and polished as well as possible. Of course I was unable to get the cup seal to seal now, but that’s alright. I had anticipated this. Using a conical shaped dremel bit the opening on the surface of the valve was carefully beveled. Now this is the clever part (or at least I thought so) – The cup seal was placed in the chuck of a drill and some polishing compound was applied to the face of the cup seal. Now I simply used the cup seal to polish the bevel on the front of the valve and at the same time shaped the cup seal exactly to the contour of the bevel. It actually worked! The cup seal seals fine. Stealing A trick from the Diamond GT’s I decided to drill some holes into the back of the valve to allow a source of gas for the hammer independent of the hole that the valve pin sticks through. Of course now that the lip is missing from the front of the valve and the cup seal actually goes into the valve somewhat. The valve pin sticks out of the valve more than it used to. The shaved valve pin was now sticking out far enough that it was not stable. It had a tendecy to wiggle around. This would either lead to the pin jamming in the valve or cup seal leaks. This was solved by substituting a Piranha valve pin.

I also wanted to try a different valve spring setup. This is the old setup on the left(the one that worked). The o-ring sealed the volume chamber in the body. The volume chamber had an indention on the end for the o-ring. The spring pressed against the washer which kept the o-ring in place on the volume chamber. The plastic washer also kept the spring from just slipping into the volume chamber. On the right is the way I am trying to get the gun to work now. Trying it with the old volume chamber there was nothing to keep the o-ring seated against the volume chamber so it would not seal. Not with loctite or sealing tape. So a new volume chamber was added that had a o-ring groove in the body of it, and it’s really shiny to boot. I guess I can return the old one now. A spacer is inserted into the volume chamber to give the tension needed on the valve spring, this may also become an easy way to adjust the valve spring tension once everything is worked out.

Well now the volume chamber seals so I prepare to test fire the gun. I place a ball in the power feed and pull the trigger. Poof, bang, zing. A ball flys out of the barrel and falls to the ground about four feet in front of me, right by the bolt. The clevis pin popped out of the hammer, the bolt flew out the back of the gun bounced of the bed of my truck and landed in front of me. It did it the next time I tried it to, imagine that. Now I have a set srew holding that clevis pin in place and the gun fires great, leading me to believe I had the bolt in upside down, but the times I’ve done that before the gun was a lot quieter( yeah, I know, I’m a moron). Anyway the gun is now firing 295-300fps at 400psi with a stock Piranha valve pin. Thats with a black main spring in the front of the gun and a red one in the back. It’s still loud, it still kicks, it still a gashog, but by God it’s almost low pressure again.