”hi can anybody tell me the latest Belleville washer setup on the fx impact please? I need to know how many there are, what are the sizes and which order they go. I took mine out and they fell everywhere. Silly me. Thanks Jim”
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Latest fx impact Belleville washer setup
- Thread starter Sagaris
- Start date
Just a suggestion, but next time you're working on something like that, take a picture of it with your cell phone before you tear down these sub assemblies.
I started doing that years ago when working on my motorcycles.
I started doing that years ago when working on my motorcycles.
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If I recall correctly, crown and impact are the same.
Maybe my Crown reg. topic is of any help:
http://www.airgunnation.com/topic/fx-crownimpact-regulator-mod-tutorial/
Maybe my Crown reg. topic is of any help:
http://www.airgunnation.com/topic/fx-crownimpact-regulator-mod-tutorial/
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You can’t take any pictures till you take the reg housing out and the washers stick to the housing as well as been on the piston as well. They fall out so easy.
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Hi mate your post is very helpful and I will give a read. Do you know the washer sizes? I’m sure my old fx impact had 0.3 and 0.4 mm washers but I don’t know the thinkness and the new ones. Thanks
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You are correct, I now recall the Impact has got B.V. washers of different sizes.......
(Sorry, sold my Impact over a year ago, and at the age of 43, it's hard to keep up with everything:--P )
However, IMO it is useless to use washers of different sizes, as the thinnest (thus weakest) ones are flattened first.
The Crown has got 0.4mm washers, the Impact a mix of 0.3 and 0.4mm.
The AOA video at 10:15 contains your answer
(however, I read somewhere that the Impact reg piston got a update and some of them have a 2mm longer shaft, so yours might be different.
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Thanks for the reply, my setup is the latest with the longer piston. I have 16 washers as standard so it’s just the order they go and I don’t know if they are all the same thickness on this one or not
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I wouldn't be surprised if the stack of the latest Impact is the same as the one of the Crown.
That would mean 16 BV washers of 0.42mm thickness.
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Ok thanks for the information. I have something to maybe go on now. I will update you if I find out for definite mate. You have been a big help thankyou 
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I can confirm that the newer Impacts have a longer piston and 16 BV washers configured as such; ()()()()()()()(), as Wetherby has indicated in his Crown reg tutorial. A friend has both the Crown and latest Impact and the reg internals look identical.
Wetherby's tutorial is essential for those who require a higher reg pressure, I have been testing washer order, quantity and stack length for a lower pressure, think 125 bar and less.
While I am no expert, I have a suspicion that the standard 16 washer setup is too strong for lower reg pressures and too weak for higher pressures. The spring stack works in opposition to the regulated air volume, helping to keep the piston away from the sealing surface or/and reducing the pressure on the sealing surface.
After inspecting all of the orings in the sample Crown that I have access too I concluded that they were all in pristine condition and that they were adequately lubricated from the factory resulting in no leaks, however I was still getting about 5 bar of upward creep over a 15 minute period, resulting in the first shot landing low. This pattern led me to believe that the piston seal was at fault.
I speculated that reducing the spring tension would help create a better seal of the piston under lower regulated pressures, Wetherby was the inspiration and deserves the overall credit, but what I did was remove two washers, still creeped, then another two, this reduced the stack length by about 1,2 mm, so as per Wetherby I shimmed the difference with shimming washers I have lying around for RC helicopter builds, but you could just turn down the appropriate washer.
This procedure has resulted in much better refresh times and the reg looks like it is now stable at around the 125 bar mark, even if I leave it under full pressure overnight. As a disclaimer I need to point out that I have a spare piston and a set of 28 brand new BV washers in case I broke or stuffed something up. Every gun is different, how the washers react under load and under different ambient and pressurized conditions is also different so please do not do this for higher reg pressures!
The Crown I played with is set at 125 bar, the hammer spring has been adjusted on Max to provide 874 FPS shooting JSB .25 25gn getting around 104 shots from 250 bar.
Wetherby's tutorial is essential for those who require a higher reg pressure, I have been testing washer order, quantity and stack length for a lower pressure, think 125 bar and less.
While I am no expert, I have a suspicion that the standard 16 washer setup is too strong for lower reg pressures and too weak for higher pressures. The spring stack works in opposition to the regulated air volume, helping to keep the piston away from the sealing surface or/and reducing the pressure on the sealing surface.
After inspecting all of the orings in the sample Crown that I have access too I concluded that they were all in pristine condition and that they were adequately lubricated from the factory resulting in no leaks, however I was still getting about 5 bar of upward creep over a 15 minute period, resulting in the first shot landing low. This pattern led me to believe that the piston seal was at fault.
I speculated that reducing the spring tension would help create a better seal of the piston under lower regulated pressures, Wetherby was the inspiration and deserves the overall credit, but what I did was remove two washers, still creeped, then another two, this reduced the stack length by about 1,2 mm, so as per Wetherby I shimmed the difference with shimming washers I have lying around for RC helicopter builds, but you could just turn down the appropriate washer.
This procedure has resulted in much better refresh times and the reg looks like it is now stable at around the 125 bar mark, even if I leave it under full pressure overnight. As a disclaimer I need to point out that I have a spare piston and a set of 28 brand new BV washers in case I broke or stuffed something up. Every gun is different, how the washers react under load and under different ambient and pressurized conditions is also different so please do not do this for higher reg pressures!
The Crown I played with is set at 125 bar, the hammer spring has been adjusted on Max to provide 874 FPS shooting JSB .25 25gn getting around 104 shots from 250 bar.
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Hi all Riazp
If the Crown you had access to is the latest spec, 16 washers, longer piston model. Then for me that is sad reading, mine due to arrive this month.
Seems that reg creep still there.
Johan at IWA has said they are working on new reg. setup .I wonder if this was the result 16 / longer piston.
Trying to ensure when my gun arrives it is latest spec by checking gun number before acceptance. Can you tell me the last 6 numbers of gun , should be something like FX C 175100 but maybe FX C 185100 . Think first two numbers are build year , third is calibre .
i am not an engineer but wonder why BV spring washers are used being seemingly temperamental ? Do they have or lose over time their spring memory? Would surmise with time or constant readjustment they would so becoming a service replacement item. Is there no better solution for operating a piston?
Have to say that you and Weatherby are contributing huge knowledge to this forum which , on behalf of others, I thank you for.
safe shooting
If the Crown you had access to is the latest spec, 16 washers, longer piston model. Then for me that is sad reading, mine due to arrive this month.
Seems that reg creep still there.
Johan at IWA has said they are working on new reg. setup .I wonder if this was the result 16 / longer piston.
Trying to ensure when my gun arrives it is latest spec by checking gun number before acceptance. Can you tell me the last 6 numbers of gun , should be something like FX C 175100 but maybe FX C 185100 . Think first two numbers are build year , third is calibre .
i am not an engineer but wonder why BV spring washers are used being seemingly temperamental ? Do they have or lose over time their spring memory? Would surmise with time or constant readjustment they would so becoming a service replacement item. Is there no better solution for operating a piston?
Have to say that you and Weatherby are contributing huge knowledge to this forum which , on behalf of others, I thank you for.
safe shooting
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@Wolfie, I am 100% sure that you Crown will have the latest regulator piston. (Mine of januari's supply also has the long piston)
I even think that all Crowns have the long piston. If I recall, only Impacts were involved. (But to be honest, I am not 100% sure)
However, no need to worry, when I spoke with Johan at IWA, he told me that the newer crowns are gonna get stiffer BV washers.
In case if your's still has the old config, it is a very easy job to swap them out for the newer ones.
Cheers, Gijs
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@Wolfie,
You are too kind, I have a huge debt to repay as I have learned a lot from this forum and haven’t really put much back in...
The Crown I have is # FX C 175558, ordered Dec 17, received Jan 18. My friend and owner of the guns has the Impact with him so I don’t have access to the serial number unfortunately...
The BV washer is a valid option where space is limited, while researching the very same question you pose I discovered Robert Lane, and his explanation is too long for me to relay, but one advantage to BV systems is easy reconfiguration vs coil spring.
All springs eventually lose tension, I feel that in the Crown/Impact BV washers are probably the best option as they are easily reconfigured for the owners specific application, one can choose compression and stack length by different order and orientation.
I believe that all new FX guns with the “Impactesque” reg will have the longer piston, stack configuration I don’t know, but both the newer guns I play with had 16 as standard.
The balance of forces in air gunning is a tricky thing to achieve, even more so if your gun can be set at 100 Bar or at 150 Bar. It is possible to design a reg that is creep free at “X” pressure, but if that pressure changes then so too should the opposing spring tension change to achieve optimal refresh and seal.
@Sagaris,
Its a .25 cal
You are too kind, I have a huge debt to repay as I have learned a lot from this forum and haven’t really put much back in...
The Crown I have is # FX C 175558, ordered Dec 17, received Jan 18. My friend and owner of the guns has the Impact with him so I don’t have access to the serial number unfortunately...
The BV washer is a valid option where space is limited, while researching the very same question you pose I discovered Robert Lane, and his explanation is too long for me to relay, but one advantage to BV systems is easy reconfiguration vs coil spring.
All springs eventually lose tension, I feel that in the Crown/Impact BV washers are probably the best option as they are easily reconfigured for the owners specific application, one can choose compression and stack length by different order and orientation.
I believe that all new FX guns with the “Impactesque” reg will have the longer piston, stack configuration I don’t know, but both the newer guns I play with had 16 as standard.
The balance of forces in air gunning is a tricky thing to achieve, even more so if your gun can be set at 100 Bar or at 150 Bar. It is possible to design a reg that is creep free at “X” pressure, but if that pressure changes then so too should the opposing spring tension change to achieve optimal refresh and seal.
@Sagaris,
Its a .25 cal
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Just out of interest. If you remove washers and make the stack shorter you increase its strength.
A longer spring is a softer spring.
Thats the way I understand it anyway.
Cheers Michael
A longer spring is a softer spring.
Thats the way I understand it anyway.
Cheers Michael
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@airsupply,
I am by no means the expert, but I do read copiously as I dislike being in the dark, this Wiki article is very good and short enough to not lose interest half way through: https://en.m.wikipedia.org/wiki/Belleville_washer
I am by no means the expert, but I do read copiously as I dislike being in the dark, this Wiki article is very good and short enough to not lose interest half way through: https://en.m.wikipedia.org/wiki/Belleville_washer
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I'm not 100% sure, but for impact you can tell if your gun has the new reg or the old reg by if it has a serial number. Older impacts with old piston do not have a serial number.
Also, the older impacts are put together as in the AOA video. Newer impacts are put together like ()()()()()()()().
The newest impacts will have a thicker washer. For now you can purchase a set of the stock washers and just double them up, (())(())(())(())(())(())(())(()). As stated above, this is only for high pressure setups. About 140+ psi.
All information is from the horses mouth
Also, the older impacts are put together as in the AOA video. Newer impacts are put together like ()()()()()()()().
The newest impacts will have a thicker washer. For now you can purchase a set of the stock washers and just double them up, (())(())(())(())(())(())(())(()). As stated above, this is only for high pressure setups. About 140+ psi.
All information is from the horses mouth
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Here is also an explanation of what causes your first shot to be low and how to setup your gun so this does not happen. Post #15
http://www.airgunnation.com/topic/fx-impact-first-two-three-shots-are-slower/#post-193229
http://www.airgunnation.com/topic/fx-impact-first-two-three-shots-are-slower/#post-193229
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Hey riazp. Thanks for the link. I understand how the Belleville washers work. The point I was trying to make is that by removing 4 washes you have made the stack stiffer not softer. You have done the same as Weatherby has done and increased the pressure needed to compress the stack.
The longer you make the stack the easier it is to compress just like any spring.
And now you’re refresh rate is quicker just as Weatherby’s is.
I have reconfigured the washers in my Crown as in Weatherby’s tutorial and have a regulator pressure just under 120bar with no creep.
The result is what counts but I think you’ve achieved the same stiffer regulator just in a different way.
Michael
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