Marauder build!

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Raden1942

Raden1942

Member
Feb 15, 2018
1,757
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California, United States
Ok so I am off to a slow start on the marauder build but I am waiting to find a marauder with a green mountain barrel to minimize cost of buying a tj or lw blank. Anyway I have a couple questions. #1 a member here is giving me a jsar valve for a 25 cal marauder. Does that fit OK with gen 1 marauders? I have only worked on gen 2 so have no idea the difference between them. #2 is there an aftermarket air tube that is light like the jsar aluminum tube and also rated to fill to 3600 to 4500. My plan it to throw a reg in there and fill to around 3600 for a few extra shots. Is there a carbon fiber option out there? I'm not really trying to have a 1700 dollar marauder so maybe this is too much to chew but I'd like to know my options. Otherwise the jsar tube is on the list. Thanks fellas I know alot of you have been in my shoes right now. I have the cash to buy an air arms s510 or similar high end kit but I am getting stir crazy and need a project!if any of you have a marauder that has a green mountain barrel you want to let go for a decent price give me a pm! 
 
I personally fill my aluminum tube to 3450 max (normally do 3250)...that gives its a yield safety factor of 2.2 (7600 psi)...and a burst safety factor of 3 (10640 psi). Now this is just my own personal opinion, but 2.x times the yield and anything over 3x burst is quite safe, for me...to each their own... Others prefer to use 2.5x for yield and 3.5 for burst...


Use the above advice at your own risk, as I do...



Honestly, why not just go with an avenger/liberty if you want a tinkerers gun. If I didn't have my marauder, and wanted a pcp right now to tinker on, it would be my choice...side lever, longer barrel, more adjust-ability, already regulated. Add plenum volume, peek poppet and some porting, and a proper baffle system and its done...for A LOT less than building a marauder...I opt out of the new avenger only because I don't want to put in a bunch of work to have two identically performing rifles, so I'll stick to the marauder I already put the money into....just my 2c.



Ps..Avoid the SS valve, its being given to you for a reason, plus it's best reserved for highly advanced pcp users that can can retrofit hot fixes where needed, now if that is you, then continue on, but imo you're much better of with a properly ported valve with a reduced peek poppet + stem...it saves both money and headache. I actually use either less, or identical spring rating to all the SS users I've spoken to and seen post their spring/hammer data...while sporting .225" porting. (7.7 lb/in for up to ~62 fpe, 6 lb/in for up to ~45 fpe, 5 lb/in for up to ~25 fpe)
 
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Hmm I have done many modifications to my marauder a 177 regulated field target and it was terrible until I tuned it and polished the barrel for hours. Now it's super accurate. That being said i am no expert. I just got into pcp's 2 years ago but have been tinkering the whole time.I trust the guy who is sending the valve to me. He actually never put it in his gun. I don't think he's giving me trash he couldn't use. That being said i didn't know the valve was a pain to use. I was under the impression that putting it in and installing a Hdd and turning it down all the way would maintain speed or even increase it and get better shot count. What exactly makes this valve a pain in the ass? Thanks guys 
 
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Just as a matter of never being called an elitist ... To this day still have 2 marauders, a gen 1 and a gen 2. Both ridiculously modified and done so on purpose and not an O'poop what have i done project with $$ regret .. On purpose !! The platform is that solid IMO.



AS too the OP's last question on whats the PITA with JSAR balanced valves ? 1st cold shot stiction where the o-ring/s required with the design are reluctant to break free after sitting a spell. Typically takes 1-3 shots to gets them freed up and sliding smoothly. Harder to get the valves to seal in general due to 1 or 2 o-rings that could leak along with reduced seat pressure because the balance chambers total area reduction has the pressure within the valve holding the poppet down greatly reduced.

Then the FACT that balanced valves tune a lot lot differently than a conventional knock open valve ... requiring often LESS hammer mass LESS spring rate required LESS stroke.

In any combination .... they have to be set up correctly to not be air hogs, tho done correctly there simply AWESOME !! ... For higher power tuning primarily.



1591466691_2378667985edbdac3ea6ef8.69884990.jpg
1591466723_13707521385edbdae3cc00e7.30398157.jpg


BOTH these have custom balanced valves in them ... 1st a Gen 1 action that serves double duty, when fitted with a .177 barrel and tune adjusted @30- 35 ft lb !! and when fitted with a .22 barrel i tune at @ 35-40 ft lbs. 2nd a gen 2 that again serves double duty, fitted with a .25 cal barrel adjusted to @ 58 ft lbs and can use the .177 barrel where again @ 35-38 ft lbs. Either gun can hang accuracy wise with my RAW, DAYSTATE, WAR or JSAR guns no problem !





Scott S
 
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Instead of asking why not, ask why to install a valve that introduces more points of failure or variation in strike needed to operate the valve nominally..resulting in looser extreme spreads than conventional (note Motorhead went away from balanced valve in his F/T rifle, as well as OldPro in his own raptor...that is kind of a hint)



I won't get into all the in's and out's...I've spread my knowledge around many different threads covering this topic, and its too long winded to repeat. My basis is not biased nor uneducated, as I support balanced valves and their evolution 100%...and have personally contributed to their advancement.
 
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BTW the reason I chose marauder is that parts are widely available, I know the gun well as I already stripped mine down multiple times, and the aftermarket parts for it are cheap and available as well. I don't really know the Nova Vista but it's not really my thing.
Click to expand...



Fair enough, I can't argue your point and in fact support it for the fact there is little part support for the Liberty/Avenger and if you're not up to the task of sourcing/fabbing yourself, then marauder is a better tinkerers rifle.



The conventional / stock valve can be ported much larger than anyone really needs with very minor care and modification (opening breach slightly for larger tp that fits the entire recess for tp on barrel and valve) If you want to tinker, buy 2 valves from crossman, and play around, (its like 50-55 shipped) and you'll probably learn some cool things. Learn to make your own poppets (very easy with drill/dremel) and you can have a conventional valve that operates very similarly to a balanced valve in small bores, while retaining a potentially very tight es with a low maintenance valve that has only 2 seals to concern you with, the outer o-ring and the poppet, as opposed to a third dynamic seal that when setup to be tuned on the down slope, needs maintenance to be consistent, or a lot of buffer to remove the inconsistency...which is absolutely unnecessary when you can match the performance 1:1 with a conventional valve setup correctly in small bores.



My old valve at .213" ports ran a .25" poppet that was incredibly easy to open...my .225" ported valve with .276" poppet requires a bit more energy but not terribly so, in fact I simply just increased my hammer weight around 20% to compensate for the larger seat/poppet od and retained the same ease of cocking that my current springs give.
 
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Yea the Green Mountain .25's went away actually IIRC near 2 years ago.



Matt is correct that In my personal JSAR raptor mini ( Which is only tuned for >20fpe operation ) for Precision Field target use no longer has the balanced valve in it.

ONLY reason doing so was that of wanting / tuning for the absolute best in consistency and low ES values. The valve as a balanced configuration is made for POWER and simply put ... did not need or want power. End of story there.



Scott S
 
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I found a marauder gen 2 from 2014 with green Mt barrel an hour away from my house. It's only 240 bucks! I will get it and try out both ways mentioned here. I will attempt to educate myself on the balanced valve and if it doesn't work out I will mod the valve. If I screw something up 55 bucks is a cheap fix. On a different line of questioning does the jsar aluminum air reservoir require any polishing or work or just throw the parts in there with a little divers grease as I normally do? I usually do some corner rounding and polishing to the inside of the standard crosman tube. Thanks guys I think thats is about it. I might have gotten into a can of worms with this balanced valve. Didn't know what a balanced valve was before this so I got some homework to do. 😊 Thanks guys
 
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While I'm not a tuning expert, have been using a 1st gen SS valve regulated in my Mrod since they were introduced.

With both Audrius regulator and now upgraded to a Huma.

I have it set now 150 bar and 45fpe with .25 Hades.

Never really had the striction issues after the valve broke in. My first couple months I did notice the fps on the 1st shot low, but I thought it was a regulator issue, and since it wasn't that high of a fps difference, I just kept shooting.

One day it just stopped, and has been a non issue. I do have another valve to back this one up if it were to fail.


 
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Fingers crossed you have one of the more functioning, less problematic versions of the balanced valve...and as you said its really a cheap easy fix if you find it not suiting you.


Great find btw! Lucky duck. 240$ with Grn Mtn? That'll do!



Just setup my mrod last night for a 24 shot 60 fpe tune and a 32 shot 57 fpe tune @ 1975 psi regulated. No balance valve needed, all modified stock valving. 50 gram hammer and 9 lb spring with little preload on the 60 fpe tune, 50 gram hammer and 6.3 lb spring with decent preload for the 57.
 
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