Marauder 2563 Valve mods
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Marauder 2563 Valve mods
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Topic: Marauder 2563 Valve mods (Read 2523 times))
PakProtector
GTA Senior Contributor
Posts: 2890
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Real Name: Douglas
Marauder 2563 Valve mods
«
on:
February 24, 2013, 12:53:44 PM »
hey-Hey!!!,
I have a modified 2563 valve in a reg'd 22 cal Marauder. Throat is .234, exhaust, sleeve and barrel port at .152 IIRC. I ran a 28 g Motorhead hammer. Reg is set at ~1k9 psi. It took all the preload to get to 825 with JSB heavies, and delivered 34 shots off a 3k fill. Gage block is a A2AG opened job from Dave.
I tried a 3/8" plenum extender of 3/4" PVC and got maybe 5 more FPS off a 15.89 gr's 800 fps tune.
Took it apart and opened the valve's cap to flow air around the spring and while I had the poppet in hand, I took its OD down to just a wee bit more than the seat impression. I left out the pelnum extender and re-assembled...and found it shooting 780...grrrrr. I have no idea why shrinking the head diameter of the poppet would *COST* me speed....any help?
Next step will be a .250 throat and .160 exhaust port on a de-sleeved 2263 valve in concert with the opened cap. Power plant is destined for a 20 cal top end with a max port in the barrel of .150. Gotta get it working for the 22 cal first though...
cheers,
Douglas
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Ann Arbor, MI, USA
My most valuable friends are the ones who will tell me I am wrong.
More valuable still are the ones who go to the trouble of making me see it.
rsterne
Member 2000+fps Club
Bob and Lloyd
GTA Senior Contributor
Posts: 26958
GTA Forums Person of the Year 2017
Real Name: Bob
Re: Marauder 2563 Valve mods
«
Reply #1 on:
February 24, 2013, 01:09:37 PM »
Can't help on the speed loss, my guess would be the lower plenum volume, but you said you only gaine 5 fps, so why lose 40?.... That's assuming you have the same state of tune everywhere else....
I wouldn't go that large on the throat for a .20 cal, even taking the exhaust port larger than the barrel port may lose you a bit rather than gain.... Using a bigger throat (and therefore sealing surface) than you need will just require a harder hammer hit.... I have been getting great results by just matching the areas on everything to the barrel port area.... with maybe a 10% larger area on the throat (seat minus stem) area....
Bob
«
Last Edit: February 24, 2013, 01:49:34 PM by rsterne
»
Logged
Coalmont, BC, Canada
🇺🇦
Dominion Marksman Silver Shield - 5890 x 6000 in 1976, and downhill ever since! 🇺🇦
Airsenal:
1750 CO2 Carbine, .177 Uber-Pumper, .22 Uber-Carbine, .25 Discovery, 2260 PCP 8-shot Carbine, 2260 HPA (37 FPE), 2560 HPA (52 FPE), XS-60c HPA in .30 cal (90 FPE), .22 cal QB79 HPA, Disco Doubles in .22, .25 & .30 cal, "Hayabusa" Custom PCP Project (Mk.I is .22 & .25 cal regulated; Mk.II is .224, .257, 7mm, .308 & .357; Mk.III is .410 shotgun and .458 cal), .257 "Monocoque" Benchrest PCP, .172/6mm Regulated PCP and .224/.257 Unregulated, Three regulated BRods in .25 cal (70 FPE), .30 cal (100 FPE) & .35 cal (145 FPE), .257 Condor (180 FPE).
PakProtector
GTA Senior Contributor
Posts: 2890
yes
Real Name: Douglas
Re: Marauder 2563 Valve mods
«
Reply #2 on:
February 24, 2013, 01:29:53 PM »
Recall that on the Marauder valve the seat diameter is set a wee bit more than .250...so increasing the throat up to that point does nothing to the sealing area. Now the 2263 sleeved valve the seat is flat, but still having a conical zone down to the smaller seat, so until we get bigger than the top of the cone, throat diameter change has no effect on seat pressure.
I have a 2563 valve with a stock throat, exhaust and sleeve in the other 22 cal, and it shoots near 900 on 2k and only drops off 'quickly 'cause of the Staley O-rings...and that with a 40 g hammer. Recall that Motorhead's valve is huge in comparison, and he gets an off-reg surge( though it is small ) that delivers another 10 shots...
A in my 25 cal, a 2563 valve( the OE gold one ) with stock cap, and .152 exhaust, sleeve and .234 throat runs 880 fps with kings on shot #16 near 2k pressure.
cheers,
Douglas
cheers,
Douglas
Logged
Ann Arbor, MI, USA
My most valuable friends are the ones who will tell me I am wrong.
More valuable still are the ones who go to the trouble of making me see it.
rsterne
Member 2000+fps Club
Bob and Lloyd
GTA Senior Contributor
Posts: 26958
GTA Forums Person of the Year 2017
Real Name: Bob
Re: Marauder 2563 Valve mods
«
Reply #3 on:
February 24, 2013, 01:49:11 PM »
Your performance increase with the big throat is on a gun that isn't ported to the maximum, so every time you make it breath a bit better, you gain a little.... My comments about hogging out the ports were aimed at your stated goal, which was a .20 cal.... with a 0.150" barrrel port.... Just because it works great on a .45 cal doesn't mean there isn't a better soluton on a .177.... At some point, the added volume between the valve seat and the pellet just costs you (initial) pressure at the pellet without any benefit from flow.... Have you ever hogged out the valve on a 1377? ....
Bob
«
Last Edit: February 24, 2013, 01:51:45 PM by rsterne
»
Logged
Coalmont, BC, Canada
🇺🇦
Dominion Marksman Silver Shield - 5890 x 6000 in 1976, and downhill ever since! 🇺🇦
Airsenal:
1750 CO2 Carbine, .177 Uber-Pumper, .22 Uber-Carbine, .25 Discovery, 2260 PCP 8-shot Carbine, 2260 HPA (37 FPE), 2560 HPA (52 FPE), XS-60c HPA in .30 cal (90 FPE), .22 cal QB79 HPA, Disco Doubles in .22, .25 & .30 cal, "Hayabusa" Custom PCP Project (Mk.I is .22 & .25 cal regulated; Mk.II is .224, .257, 7mm, .308 & .357; Mk.III is .410 shotgun and .458 cal), .257 "Monocoque" Benchrest PCP, .172/6mm Regulated PCP and .224/.257 Unregulated, Three regulated BRods in .25 cal (70 FPE), .30 cal (100 FPE) & .35 cal (145 FPE), .257 Condor (180 FPE).
PakProtector
GTA Senior Contributor
Posts: 2890
yes
Real Name: Douglas
Re: Marauder 2563 Valve mods
«
Reply #4 on:
February 24, 2013, 02:55:24 PM »
Never messed with a 1377( or even owned one). I understand what you're saying on the port size, and I think I'll give the huge 22 cal valve a try before I leave it alone for a while. I think I'll try the OE, 79 g hammer...
cheers,
Douglas
Logged
Ann Arbor, MI, USA
My most valuable friends are the ones who will tell me I am wrong.
More valuable still are the ones who go to the trouble of making me see it.
PakProtector
GTA Senior Contributor
Posts: 2890
yes
Real Name: Douglas
Re: Marauder 2563 Valve mods
«
Reply #5 on:
February 24, 2013, 03:52:46 PM »
hey-Hey!!!,
The 79 g hammer gave the predicted results that lead to the implementation of the light hammers in the first place. Am going to try the light hammer again with the set-screw travel increaser. I may try it with two, one slightly longer to add a wee bit of mass...but I suspect Bob has it right and the 20 cal will behave differently...come on LW and deliver my barrel to Jim Gaska...
Logged
Ann Arbor, MI, USA
My most valuable friends are the ones who will tell me I am wrong.
More valuable still are the ones who go to the trouble of making me see it.
PakProtector
GTA Senior Contributor
Posts: 2890
yes
Real Name: Douglas
Re: Marauder 2563 Valve mods
«
Reply #6 on:
February 25, 2013, 06:03:36 PM »
hey-Hey!!!,
I think I now have an idea about what is going on. I put in a 10# spring and with minimal preload I got 880 fps out of 15.89's. On a fill to about 2k6 psi I got 20 shots on reg, and another 10 as reg pressure dropped off( with the light hammer). I suspect if I had kept shooting at the lower hammer energy I would have seen a small surge at lower pressure...so, as hammer energy goes up, the shot string curve peak also goes up in pressure and the peak gets higher...so it is a matter of matching them up.
cheers,
Douglas
Logged
Ann Arbor, MI, USA
My most valuable friends are the ones who will tell me I am wrong.
More valuable still are the ones who go to the trouble of making me see it.
rsterne
Member 2000+fps Club
Bob and Lloyd
GTA Senior Contributor
Posts: 26958
GTA Forums Person of the Year 2017
Real Name: Bob
Re: Marauder 2563 Valve mods
«
Reply #7 on:
February 26, 2013, 12:10:10 AM »
Any surge in velocity should occur just after you go below the setpoint.... If the hammer strike is too high, the velocity will drop off immediately below the setpoint.... If it is significantly too light, the velocity will increase below the setpoint, peak, and the fall off.... When it's "just right" the shot string just continues past the setpoint with hardly any change in velocity, because you are tuned for a peak in the bell-curve just 100 psi below the setpoint or so.... so you get an extra 200-300 psi before the velocity drops off....
Bob
Logged
Coalmont, BC, Canada
🇺🇦
Dominion Marksman Silver Shield - 5890 x 6000 in 1976, and downhill ever since! 🇺🇦
Airsenal:
1750 CO2 Carbine, .177 Uber-Pumper, .22 Uber-Carbine, .25 Discovery, 2260 PCP 8-shot Carbine, 2260 HPA (37 FPE), 2560 HPA (52 FPE), XS-60c HPA in .30 cal (90 FPE), .22 cal QB79 HPA, Disco Doubles in .22, .25 & .30 cal, "Hayabusa" Custom PCP Project (Mk.I is .22 & .25 cal regulated; Mk.II is .224, .257, 7mm, .308 & .357; Mk.III is .410 shotgun and .458 cal), .257 "Monocoque" Benchrest PCP, .172/6mm Regulated PCP and .224/.257 Unregulated, Three regulated BRods in .25 cal (70 FPE), .30 cal (100 FPE) & .35 cal (145 FPE), .257 Condor (180 FPE).
Motorhead
Field Target Shooter .... Stand em up Shoot em down
GTA Senior Contributor
Posts: 17762
2019 GTA Hall Of Fame Recipient
Real Name: Scott
Re: Marauder 2563 Valve mods
«
Reply #8 on:
February 26, 2013, 12:25:55 AM »
Douglas,
Have received some more data from another tuner I have been working with in an attempt to dupicate my test results using the 28 gram hammer at 1850# regulated pressure using the .177 / .22 valve MODIFIED.
It would seem when he did the mods near to a T .... this resulting string was the reward being SOOOO close to my original result data it's spooky !
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Northern California ... Old Hangtown
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Marauder 2563 Valve mods