tiff_lee Posted December 28, 2007 Report Share Posted December 28, 2007 Just out of interest really when shimming the piston assembly for a good angle of engagement with the sector gear is it a must to remove the first two teeth after the pickup tooth? The only reason I ask is because in the pic of it with spacers the sector gear would of hit those teeth before it actually came in contact with the pickup tooth whereas had it not been fitted with spacers and left with a poor angle of engagement it would of meshed correctly with the teeth left in place. Link to post Share on other sites
Cam Keo SOC16 Posted December 28, 2007 Report Share Posted December 28, 2007 Deepfire pistons ftw. Link to post Share on other sites
shinhk Posted December 28, 2007 Report Share Posted December 28, 2007 Just out of interest really when shimming the piston assembly for a good angle of engagement with the sector gear is it a must to remove the first two teeth after the pickup tooth? The only reason I ask is because in the pic of it with spacers the sector gear would of hit those teeth before it actually came in contact with the pickup tooth whereas had it not been fitted with spacers and left with a poor angle of engagement it would of meshed correctly with the teeth left in place. that's something i was wondering as well. I don't remove the teeth mainly because i never saw it to be a problem. But looking at those pictures makes me wonder if it does more harm than good? w/o those 2 teeth removed though that first engagement might have had a little stress on it but immediately afterwards it would have meshed nicely with the rest of the teeth. It's almost like you're fixing something you messed up to begin with. That's probably what marui figured out early to begin with so they added that thicker end to the piston to help the added pressure on the initial tooth. I would think if you wanted to reinforce the piston have the very first tooth made of aluminum. Relating to the topic at hand though, these pictures are what maxxxmonster should take pictures of. Maybe that way we can see how the other aftermarket pistons are "meshing" with the jg gears. Link to post Share on other sites
RSM Posted December 28, 2007 Report Share Posted December 28, 2007 The reason those two teeth are missing is because of Corvid's high speed set up. Removing teeth like you see reduces the chance of the sector gear coming around and picking up those teeth now missing, pulling the piston back and ripping through the tooth it grabbed and the tooth it should have grabbed when the piston cannot go back any further. Link to post Share on other sites
maxxxmonster Posted December 28, 2007 Author Report Share Posted December 28, 2007 very nice i gotta do some modding now... Link to post Share on other sites
Blink43va Posted December 28, 2007 Report Share Posted December 28, 2007 Hmm.. this is quite interesting! I wonder if this is what is causing my feeding issues, which I have NEVER experienced... yet it is a high speed setup! Gunna check this out! I got a ###### load of TM Pistons for super cheap... gunna go get some more! BTW, Corvid, what material did you use for shimming the piston head? Thanks, -Blink Link to post Share on other sites
shinhk Posted December 28, 2007 Report Share Posted December 28, 2007 ah...okay i understand how it could help a "high speed" setup now. Link to post Share on other sites
tiff_lee Posted December 28, 2007 Report Share Posted December 28, 2007 Believe me I more than appreciate removing teeth for high speed setups I have one of my own at +40rps but the point I was trying to make is that if you were aligning the sector on a non high speed setup the teeth would still need to be removed otherwise the sector would hit them. Link to post Share on other sites
Corvid Posted December 28, 2007 Report Share Posted December 28, 2007 Corvid you legend! Glad you put those pictures up mate, I could never be bothered to strip down one of mine and take a few snaps. Top man, that'll make it much easier for people to understand. No worries! Feel free to use them as you please to help further the cause . I may make some more in the future, I was hard pushed to get those photos with my old camera. My new camera is a dream to do macro with though, so I'll get some snaps next time the gearbox is open! The reason those two teeth are missing is because of Corvid's high speed set up. Removing teeth like you see reduces the chance of the sector gear coming around and picking up those teeth now missing, pulling the piston back and ripping through the tooth it grabbed and the tooth it should have grabbed when the piston cannot go back any further. Spot on mate, the piston shown there is cycled at 32RPS. I wonder if this is what is causing my feeding issues, which I have NEVER experienced... yet it is a high speed setup! Gunna check this out! I got a ###### load of TM Pistons for super cheap... gunna go get some more! BTW, Corvid, what material did you use for shimming the piston head? Assuming you are talking about angle of engagement... I wouldn’t think that it would affect feeding in any way. What it WOULD affect is guns that rapidly wear down the pickup tooth, or regularly tear the back of it off. Although at some point the velocity of the sector (or extra resistance from a very strong spring) is going to start taking the pickup tooth off anyway. Link to post Share on other sites
Blink43va Posted December 30, 2007 Report Share Posted December 30, 2007 Ok, that makes sense. Could you tell me, Corvid, what material you used as the buffer between the piston and the piston head? Thanks so much! -Blink Link to post Share on other sites
Magsz Posted January 1, 2008 Report Share Posted January 1, 2008 Making an appropriately sized spacer out of nylon washers or other round material is a better solution to the metal washers. I just thought i would offer that up for the people interested in saving .000002 ounces. The only thing that concerns me is the durability of the nylon but i think it should be ok. Link to post Share on other sites
Morfoot Posted January 2, 2008 Report Share Posted January 2, 2008 Believe me I more than appreciate removing teeth for high speed setups I have one of my own at +40rps but the point I was trying to make is that if you were aligning the sector on a non high speed setup the teeth would still need to be removed otherwise the sector would hit them. I noticed this too, you'd definitely lose teeth if you aligned the cylinder in this fashion without having previously removed them. I guess the alignment in a stock gun must be similar to the before photo, it's just that in a stock gearbox, the standard rof isn't enough to wear away the tooth to a significant extent? I might go out and take apart a stock marui to see if there are any signs of wear on the thick base tooth. It's almost like you're fixing something you messed up to begin with. That's probably what marui figured out early to begin with so they added that thicker end to the piston to help the added pressure on the initial tooth. I think you're right there, only it's necessary to 'mess up' the working of the gearbox by removing teeth in order that the high speed setup runs smoothly and then fix that with a realignment of the cylinder. It begs the question; does the damage on the thick tooth degrade it to a point where it would actually affect gearbox operation? Link to post Share on other sites
tiff_lee Posted January 2, 2008 Report Share Posted January 2, 2008 To emphasise my point here is a somewhat crudely paint edited photo after alignment has been adjusted, I have pasted in the original teeth showing that in this case the sector gear would actually shred them had they not been removed. So is it safe to say when aligning the sector gear the 2nd and 3rd teeth need to be taken into consideration and removed as well? Personally I always remove them but I know some people are more apprehensive about taking such measures. Link to post Share on other sites
maxrezn Posted January 2, 2008 Report Share Posted January 2, 2008 To emphasise my point here is a somewhat crudely paint edited photo after alignment has been adjusted, I have pasted in the original teeth showing that in this case the sector gear would actually shred them had they not been removed. So is it safe to say when aligning the sector gear the 2nd and 3rd teeth need to be taken into consideration and removed as well? Personally I always remove them but I know some people are more apprehensive about taking such measures. You must remove the teeth. I have a gearbox apart on my floor and I just tried seeing what happens when the piston is pushed back further than it is stock. The teeth on the piston would shred. Link to post Share on other sites
Angry Posted January 2, 2008 Report Share Posted January 2, 2008 The problem Might just be the fact that you are running a systema magnum with M130 spring and 10.8v battery on a polycarb piston , lol. Yeah that. I've dumped my Systema Turbo because even with a 9.6 it keeps destroying pistons. Link to post Share on other sites
Corvid Posted January 2, 2008 Report Share Posted January 2, 2008 You must remove the teeth. I have a gearbox apart on my floor and I just tried seeing what happens when the piston is pushed back further than it is stock. The teeth on the piston would shred. Yup! But then again, if you don't have a reason to remove those teeth, you don't really have a reason to perfect the angle of engagement. Stock Marui guns (and moderate RoF guns over 1J) are testimony to this. I suppose high FPS set-ups would be an exception... I don’t think teeth are generally removed from the piston in such guns unless they are high RoF as well. Although I would say removing those teeth in order to perfect the angle of engagement WOULD be beneficial. Meh, I know next to nothing about high FPS guns, someone outside the UK will have to try this out! Come to think of it, I’d say it’s exactly the same principle. Besides the fact the piston cycles faster and therefore will theoretically fail faster even under ideal conditions (if you assume the piston has a predetermined lifespan!), it is the extra momentum the sector gear has that changes everything (in high RoF guns at least). As you increase the overall RoF of the gun, the speed at which the sector gear spins (with no load) is going to increase considerably. Increasing the speed increases the momentum, meaning the gear hits the pickup tooth a lot harder. This "incorrect" angle of engagement is fine on stock AEGs because of the relatively low momentum of the sector: anyhow, as people have pointed out, you can't really change this angle much without removing teeth, something that the vast majority of people do not do. In high FPS guns, the momentum of the sector gear hasn't changed much, but the resistance it gets from the stronger spring accounts for the extra wear on the pickup tooth (and other teeth in general). Much in the same way that a perfect angle of engagement helps high RoF guns, I would think that a perfect angle of engagement (removing as few teeth as possible to achieve it) would considerably help people running high FPS guns. I always hear (on other forums mind you!) how people rip through pistons in high FPS gearboxes within a few thousand rounds... yet people running guns at 40+ rps are getting tens of thousands of rounds out of their pistons. It makes me wonder... could it be that the high RoF guys with their light pistons and lower FPS springs, who have deemed it beneficial (and necessary!) to remove teeth are getting better piston lifespan because of being able to adjust the angle of engagement? I say this because I really can't imagine people with M-whathaveyou springs cutting teeth of their pistons... meh, enough rambling for now! Yeah that. I've dumped my Systema Turbo because even with a 9.6 it keeps destroying pistons. In that case you are not doing something right! You can hardly be blamed... without Ice and various other high RoF gurus here you'd probably be laughed at for trying to get your gun to firing at that speed reliably! Arnies certainly benefits from its vast number of members at times! I feel a lot of people buy such motors and end up not using them because they assume that 25rps destroying pistons every other game is just a fact of life! When actually, there’s plenty of ways to get guns running reliably at 40+rps as the "Gurus" will tell you if you ask nicely Link to post Share on other sites
tiff_lee Posted January 2, 2008 Report Share Posted January 2, 2008 In that case you are not doing something right! You can hardly be blamed... without Ice and various other high RoF gurus here you'd probably be laughed at for trying to get your gun to firing at that speed reliably! Arnies certainly benefits from its vast number of members at times! I feel a lot of people buy such motors and end up not using them because they assume that 25rps destroying pistons every other game is just a fact of life! When actually, there’s plenty of ways to get guns running reliably at 40+rps as the "Gurus" will tell you if you ask nicely Very true, I have a systema turbo running a 12V battery (with MOSFET) and the trouble I'm having has nothing to do with the piston. This probably isn't the place to discuss it but if you start a new thread detailing your setup i'm sure we'll all be happy to help out! Link to post Share on other sites
maxrezn Posted January 2, 2008 Report Share Posted January 2, 2008 I'm in the US and an airsmith so I've done about 35 guns and a few high FPS guns too. Usually what I notice is that for FPS over 400 you still need to remove the 2nd and 3rd tooth simply because it does no harm. When you do this, it allows you to set the angle of engagement. When it's set properly, the piston is less likely to strip because the sector gear has a much greater contact area to pull the spring with. Link to post Share on other sites
Lon Posted January 3, 2008 Report Share Posted January 3, 2008 Very interesting info guys; I'm trying to make a high speed G3, and I've noticed the first tooth (thick tooth) of the piston has some major wear, even only after around 5K rounds @ 340-350ish fps tops. I've heard about removing the 2nd and third teeth to increase reliability, and I finally see how it's done thanks to Corvid's pics. I'll try it with a new piston once this piston strips... Link to post Share on other sites
Corvid Posted January 3, 2008 Report Share Posted January 3, 2008 I'm in the US and an airsmith so I've done about 35 guns and a few high FPS guns too. Usually what I notice is that for FPS over 400 you still need to remove the 2nd and 3rd tooth simply because it does no harm. When you do this, it allows you to set the angle of engagement. When it's set properly, the piston is less likely to strip because the sector gear has a much greater contact area to pull the spring with. Just as I thought! Is it commonplace for the angle of engagement to be adjusted in high FPS gearboxes? As I was saying earlier, I always wondered why some people repeatedly had the pickup tooth smashed of their pistons or worn through when using very strong springs, while others claimed to run insane FPS levels with relative reliability... looks like that’s the reason (or one of the reasons) why. Good to know that both the extremes (RoF and FPS) can benefit from that technique. Very interesting info guys; I'm trying to make a high speed G3, and I've noticed the first tooth (thick tooth) of the piston has some major wear, even only after around 5K rounds @ 340-350ish fps tops. I've heard about removing the 2nd and third teeth to increase reliability, and I finally see how it's done thanks to Corvid's pics. I'll try it with a new piston once this piston strips... They weren't really about removing the 2nd and 3rd teeth, that’s kinda one of the very first things that’s done in a high speed gun pretty much as standard. If you're getting severe pickup tooth wear (or failures related to the pickup tooth) you could probably do with adjusting the angle of engagement as shown in the photos. Link to post Share on other sites
Cpt Posted January 3, 2008 Report Share Posted January 3, 2008 Use Deep Fire piston, their teeth are made from aluminum. No. Their teeth are made out of steel and then coated with titanium. Link to post Share on other sites
aim2please Posted January 6, 2008 Report Share Posted January 6, 2008 titanium nitride actually. Link to post Share on other sites
CptNemo Posted January 7, 2008 Report Share Posted January 7, 2008 Does anybody know how i can check the allignment on ma 8mm prowin? Link to post Share on other sites
Sale Posted January 7, 2008 Report Share Posted January 7, 2008 titanium nitride actually. Except that TiN is gold in color, but the DF piston tooth rack is not. -Sale Link to post Share on other sites
alencore Posted January 7, 2008 Report Share Posted January 7, 2008 i have my own share of high rof guns and lately i simply jack in a 12 volts nicad large pack on my jg dragunov with a sp130, all stock, 20-23 rps no modification on the piston body and still no stripping yet after months of use. so guess my set-up is doing well so far. Link to post Share on other sites
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