Talon valve mod (repost) – bodhisdad
I have done a couple of these mods to the talon valve have found it will yield at least 100fps to a stock TalonSS. I like the custom valves as well, but this mod gained me 100fps with a delrin retainer which i did not drill out the center of the retainer. I’m hoping for a litle more fps increase. Last mod went from shooting 16g JSBs 800fps to a little over 900fps with a 12″ barrel. Jon got over a 1000fps with a 18″ barrel and the modded valve, not bad at all. 75 gram hammer and full preload. Do it yourself and you have a custom valve which produces quite a bit of power at a fraction of the cost.
here is a new stock Talon valve ala FJR disassembled.
This is the stem with tophat removed ready for drilling
Here is the modded stem/tophat next to a stock one the porting of the stem does remove material but is hard to see via the eye, i also did some work on the two port holes ovaling and opening them up a bit. Needle files and diamond Dremel bits work well. Polished with fine miro sanding medium. This material works awesome and a link should be supplied. AAHHH Mike? As you can see the difference in the polished one vs. the stock one, no comparrison. I have to believe this helps in opening the valve due to less friction as the smoother surface is like butter compared to the stock one pictured you can even see the tool marks from machineing.
Here is the spring retainer top view and bottom view i drilled out the center and gained some space as you can see the difference in the photo.
I used the bit mike discribed for the funneling of the bottom. Talked with CygsX about this a while ago and as the photo shows the air flow will have a much easier time getting to the stem ports via a funnel vs. what stock configuration offers. Which is a flat inefficent hole on the bottom. The small tool in front, is a polishing device from dremel, worked great on the cavity as i ran it through the enlarged air passage. The tool is a rubber like material with a grit impregnated into it. The material does wear out quickly but is useful for areas such as this, as is the other sizes this bit comes in.
Have not tested this valve yet as AF has left me with a stem which has less then enough threads. I can only turn the tophat down to around .075 Confused Yaaa, i have talked with Denskin about this and will turn some threads later today, fill her and give you guys the before and after results. The pic below is a possible replacement spring if needed will test with factory spring first and see what numbers i get and with what hammer. The stock spring is the larger of the two.
Any replies, suggestions would be welcomed. Hope the pics help, if any wish to tackle this themselves the info is all here, and so are we. Pretty easy to do if you have the tools, a chrony for the tophat adjustment, and a set of feeler gauges. Feel free to PM me if you have questions as i’m sure Mike would help you out as well.
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Thanks so much for the help BD!! A lot to learn here. I do need to get a chrony. But it being Christmas, I had better lay low for a while.
Barrel or Chrony? Decisions-Decisions. I would have enjoyed testing the before and after. But I have a feeling the need,(Want) for a new barrel will win out first. Haa!!! 😀
Any one have a .22 18″ bbl. laying around for sale? Have a GTX. in .177 with less than one tin thru it. Has custom trigger in it. Not a bad gun at all, but I own a Talon. Who needs a springer? Haa! Mike
If you lighten the spring it gives more consistent shots from the start. I also went back to a stock hammer vs.75g . I got a variety pack from century spring and used one in which i could depress the tophat manually. Also turning in the tophat counteracts the loss of air.
Yeah, because the valve stays open longer and lets more air out, but the pellet has already left the muzzle. The pellet has to be accelerated with 1 large, quick burst of air, not a long strong burst. Thats my theory anyway.
You can put 4-5x weaker valve return spring if you enlarge valvestem to 8mm. Then you can have very big bore through the stem and transfer required air very quickly with shorter stroke.
Standard Talon’s valvespring is about 100N and I replaced it for 20N spring. 8mm valve stem with 4.5mm or so bore. It can shoot with 70bar (~1000psi) without valvedump.
What ever you experiment it is wise to writedown values to have concrete data to compare afterwards. Measure the pressure before and after string so you can calculate the air usage efficiency. Measure the velocity and calculate summed ME. etc.
I have special test-chamber setup with digital gauges now but when using standard tank and valve I use this kind of adapter to check the accurate pressure before/after. No need to open the valve with filling-pressure.
Yeah, because the valve stays open longer and lets more air out, but the pellet has already left the muzzle. The pellet has to be accelerated with 1 large, quick burst of air, not a long strong burst. Thats my theory anyway.
Those are some great pics of your operation, as well as some excellent results. I like that bored and polished valve retainer a lot!
I’ve been experimenting with shims under the tophat with good results…if you didn’t want to mess with cutting more threads? I posted them in the SS section…
Did you try the o-ring mod also? I’m definitely getting a good amount of blow by on my valves(they aren’t o-ringed yet).
It would be REALLY cool if you can take some chrony strings before and after if you change the valve spring to a lighter one(stock vs. light)… my first test this weekend showed the lighter spring was using a lot more air for the same velocity as the stock spring, like 18+% more air.
Definitely thanks for sharing your findings and nice instructions on how you did it. Jim.
Bodi
I did not replace my valve spring. What size are you using?
Looks like you did a great job. Glad your happy with the mod, i know i was when i did it. + or – 100fps additional velocity for a few hours work is well worth it. Just think add an 18″ barrel and you’ll gain around 90fps, 6″ shroud and your pushing JSBs at 990 or so Kodiaks at 930-920. One of the best mods a guy can do to a TSS rig. See if you can get a chrony, and feeler gauges could save you alot of air. Top hat setting on the last valve i did was set at .058 anymore and i didn’t see any increase in velocity so its just wasting air. would have turned it in further but ran out of threads. Glad i could be of some help.
The Stem was reamed out to 1/8″ and internally polished. The top hat Radius ed and polished. I didn’t have a smaller spring, so the out side diameter was ground and polished apx. .004 smaller in Dia. This made in noticeably lighter.
Even though the inside diameter looks hung in the pic, there is a very gradual radius entering the retainer. Because of th high finish, it in actually magnifies what you are seeing. I didn’t expand the ID. that much as the spring dia. blocks the edges as it is.
I thik this shot may show the radius a bit better. Mike 
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Well lyou guy’s talked me into it. I couldn’t resist. I did the valve mod yesterday, and “WOW”, talk about a mod that works!!! Man I wish I had a Crony! I do have several test I use. One is the old soft wood thing. The 12″ barrel world put a 14.3 CP at an averge of 1 1/4″ deep into the wood at 10 yards. It is now getting 1 1/2″. This was at 2600 lbs. fill. Filled to 2900, and it went 1 5/8″.
She is a bit louder now, and the front section of the LDC is a friction fit. Before, it never moved. Now it walks about 3/32 forward with each shot. Deffinately moving more air. What supprised me is that the shot count didn’t go down. In fact, it went slightly up. When sighted at 35 yards, it would drop apx, 1 to 1.5″ at 50 yds. Now she is is dropping only 1/2″ to no more than 3/4″. I swearer that it seems to group a little tighter. Propped on one knee for a rest, it shot 1/2″ by 5/8″ at 55 paces. (Apx. 55 yds). Can’t wait to see what she can do with an 18″ Barrel, and Kodiak’s. This thing is going to be a real Texas critter gitter for sure.
Please excuse my lousy photo skills, but I did want to post a few pic of the valve mod for you evaluation. A big thanks to BD, Body, and Dnc. Mike
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Thanks Guy’s! Still trying to make up my mind whether to go with an 18″ in .20 or .22 . Never wanted a .20, but since pyramid sent the .20 by mistake, I have learned to really like it. I was taking a look at the Theoben Rapid MFR-XP, our take-velocity chart at straightshooters.com. It is the only place I have see a side by side comparison of the BX of the .20 and .22 side by side. Seems the .20 is slightly better at retained velocity and energy. At least until you get to the Kodiak. in the .22 Cpl’s are better in the .20.
Bodhisdad, I used both. Have the factory shroud,(Frame) stuffed with perforated pvc, and thick scotch bright like pad, followed with baffles. To this I added a 3.5″ in length pvc 1″ ID, with additional 1.f chamber and the rest with additional baffles. Works very well so far. Had some clipping problems. Solved now. Just shot a .121″ Group with no tipping. This was only at 20 Yds. Seems to hold slightly under 1/2″ at 50 yards. Don’t have a bench. Just leaning across the top of the car. So far-so good.
I want to try your valve mod, and the longer barrel at the same time. should be good medicine for the Squirrels, Raccoons, and opossums here. Most shooting at game is at 50-75 yds. this is why I need the added velocity, and fpe.
Once again, thanks everyone! Mike
Good to see you here, also glad i could be of some help. If you have any questions on the valve mod let me know. I do know i got 1000fps with my 18″ barrel in .22 with the mod. Thank Adam for the shroud additions. Which one did you try??? The baffles or the PVC shroud? I feel the thick walls of the plastic help in reducing the report as it doesn’t resonate like metal. I’d still like one of ali but lack a lathe so came up with the PVC one. Once painted no one would know, if its quiet thats all that matters and its easy and cheap to build.
Knife,
Welcome and glad you found us. You are going to have a good time here. A 18″ barrel will give you a lot more power that is for sure.
BTW Love your Loveless style blades. I should have bought one of Bob’s knifes when he lived in Riverside which is not far from me.
Once again welcome!
Thank’s so much for posting this. I saw it on the other forum before it went tit’s up. A shame.
I have been playing with the .20 Talon I got in a few weeks ago. So far so good. Tack driver! Would like a little more punch though for these tough Texas Critters! I need to get rid of this .20X12″ Barrel and install a .22×18″. Just need to find a place for the .20 Still can’t believe how accurate it is.
Tried the shroud mods you suggested a couple of weeks ago. Worked just fine. Thanks again! MIke http://knifelegends.com/
My friend Mikemv is a pilot?? I think were getting close. All i know is its perfect for some of the fine tuning we do with our rigs. The pics say it all, i did the polishing by hand so as not to remove any material from the outside of the stem. One could chuck up the stem in a drill press and do it quicker, but could also remove a little to much and end up with a leaky valve stem.
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And Thank’s BO’s. Nope, no “o” ring mod. Wish I had a lathe. I would do it up. It would have to make it a bit quiter! Mike