MORE WILDCAT EXPERIMENTS

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Yesterday I received some parts from FX USA...Jessica seems to have everything in the parts department running very smoothly and efficiently now by the way. What a great gal!

I have a brand new valve seat, valve pin, valve return spring, etc., and also a new feeding pin (the pellet probe), and tomorrow they are shipping me a new brass barrel inlet. I ordered these parts because I have a few more experiments I want to do. 

One thing I am going to do is enlarge the transfer port in the brass barrel inlet, and also the transfer port in the pellet probe accordingly. Just to see if there is any change, and if so whether it is a beneficial or detrimental change.

I also wanted to look at the valve seat and valve pin in my hands and try to imagine if it would be possible to open up the valve seat hole a little larger, and yet still have the valve pin make a seal without leaking. And it won't hurt to have these parts for spares even if I don't modify the valve seat.

I also want to see what effect a lighter/smaller valve return spring will have...and whether or not it will allow less hammer spring tension and more open dwell time after the hammer hits the valve pin. 

I even thought about drilling the hole in the block larger to increase the airflow... I am guessing this is what FX did to increase the airflow on the new Wildcat MKII! Must have read my mind...

The one thing I had to get squared away before I could do any of these other things was to find the most efficient and consistent regulator possible. As you know, I solved that factor in the equation by having Huub create a Huma regulator for my Wildcat, and which fits and works perfectly in my Streamline also by the way.

I just like to tinker, but both of my rifles have the accuracy to make them worth the time and expense. If they weren't accurate I wouldn't even bother. I may purchase a Wildcat Mark II in March or April and transfer some the things I have learned over to it. I have proven that my Wildcat is capable of higher power, and that even at 900 ft/s these MKII pellets are accurate. Now I am hoping that by a little more experimenting and modification I can have this high power - 55 to 60 fpe - and yet be able to have a decent shot count to go along with it. Having my cake and eating it too, so to speak. We will see how it goes...

I have been asked about the dimensions of the valve seat, so I will put up a couple pics of it with my calipers below in a few minutes.

Always the best, Chuck
 
Here are a couple pics showing 8mm OD and 5.5mm ID of the .25 Wildcat valve seat...maybe I could use my Dremel tool to make the hole bigger?
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Watch out on the Arms race for power you cautioned me on last year. I'm tring to live in the lower 800 fps averages with heavies and 50ft/lb catagory Chuck and you keep filling my mind with this new information. I think it's great and will be watching your experimental mind at work. Keep the information coming I will try to hide in the hunting threads while you tinker. 
 
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I've never been able to do precise work on metal with Dremels. I would personally have a hard time evenly opening up the port with a free hand tool, and I'd be worried about marring up the valve seat.

If I were to do it, I would use a set of index/numbered/lettered drill bits, and enlarge with a drill/drill press and stick the part in a vice or jig.

Here's a download chart on drill bit sizes that might be handy if you go down this route.
http://www.smithbearing.com/images/pdf/ENG-FractionalChart.pdf

A #1 & 2 drill bit would slightly enlarge to 5.6-5.8mm ish, and lettered bits A, B, C, D would get you closer to 6mm. Whatever you do, please don't buy these drill bits from Hazzard Fraught (Harbor Freight) though.

 
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Yes Robert I still feel the same way too, but I just had to find out if it was possible to shoot these Heavies at higher velocity and still be accurate. What got me started was a story I read about the modified Edgun modified to shoot at 60 fpe and wondered if I could get my Wildcat and Streamline to do that too. And discovered that not only will they do it, but they will shoot the MKII like lasers all the way up to 900 ft/s. Now I am hoping to see if I can get them to give me more shots to go along with the power...but there are no free lunches. 

In the end I will more than likely set both of my rifles back down to around 830 ft/s, because I am only shooting paper it doesn't matter how much energy the pellet has when it hits the target... as long as I have the kind of accuracy you now have I am a happy camper. But one of the other reasons for the 55-60 fpe experiments was to see what effect it would have on the size of my groups at 100 yards. I already shoot tighter groups than a lot of the guys with powder burners do, which feeds my onery side. Hee Hee! ;-) 

I am thrilled that you have reached that Zen moment of oneness with your Wildcat which is the epiphany of all shooters I think.
Always the best, Chuck
 
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Good point trailryder, I'll agree with that. He would need to dress/polish after enlarging anyway, and though a high quality drill bit will leave behind a better finish than a Dremel, a reamer will leave a better finish behind than a drill bit.

The one benefit I can think of to argue for use of drill bits is cost though. It's cheaper to span a size range in drill bits than reamers, especially when we don't know what the target ID should be. But if you really wanted to be low budget about it, wrapping sandpaper around your existing drill bits is as affordable as it gets.
 
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Wow Jimmy that is a nice picture! Your right...from 4mm up to 5.5mm is a lot! I think maybe I should try enlarging the transfer ports first and see what happens...I can easily envision a slow leak at the valve seat if I don't get it right...and must think of how much to gain versus what to lose. Well off to bed for now, back to work tomorrow. God bless all!
Chuck
 
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And you know what else I just thought of? There is an o-ring on the outside of the valve seat...so how deep does the o-ring groove go? I would hate to start making the hole larger and accidentally go far enough to cut into that o-ring groove! Good thing I thought of that now...get your calipers out and measure the depth of that o-ring groove Jimmy. 
 
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Hey Robert, I have some numbers here that are going to make you feel even better about what you have accomplished with your gun so far....These are the numbers taken directly from Steve's new video review of the new Wildcat MKII...
Hi-887 ft/s
Lo-858 ft/s
Avg-873 ft/s
ES-29 ft/s
SD-6.76 ft/s
FPE-43
Shots-60
...and thanks for the hat tip by the way. My hats off to you too for what you did with putting a Huma gauge in the Wildcat air bleeder hole and the stock cutout. I have been thinking about that and am wondering about using a Forstner bit to make a hole in the stock big enough so that I can put a mm socket on the air gauge and screw it in the hole. It would look good but the drawback would be that I would have to remove the air gauge to remove the stock...so all things considered I think your idea is the best one of all.
Always the best, Chuck
 
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Watching with interest Chuck. Recently acquired a wildcat in 25 and there was a huma installed before I even sent 50 pellets down the tube. MUCH tighter extreme spread! Even managing 920's with a 140 bar set point.

Are you going to try one mod at a time and see what each of the results are? I'm most curious about the lighter valve spring. Earnest was getting 880 with the heavies with a heavy hammer and 155 bar with the stock smaller plenum. Wondering if a lighter valve spring will give more dwell and produce the same results.

Have fun tinkering!
 
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Chuck. Really interested in your Wildcat projects. Thumbs up. Just bought a 177 Wildcat to go along with my 22 and 25 wildcat. I've gotten so into the Wildcats since they came out that I'm seriously thinking of selling my Impact and Crown just for lack of use. In your opening up of the breathing don't underestimate the great effects of simply porting and polishing. Rounding the 90 deg corners, sanding out the existing machine markings and polishing to a mirror finish with Flitz and a dermal will give you another measurable step. Keep up the great posts. Sylvan
 
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