What do flat pistons and valves do for a 1377? Do they give the gun more power?
I'm really looking to turn the power up on my 1377, possibly convert it to a .22 if i can keep high FPS and FPE.
Also, will a longer barrel increase fps? I can't see how it will, but I have heard that it does.
THanks...
jj
[youtube]https://www.youtube.com/watch?v=uIIG-aa3VrM#]1377 piston and valve mods[/url] This might help !
Mike
a longer barrel will absolutly increase FPS. i dont know much about flat top pistons/valves though
Mike @ 2:35 the term your looking for is it gives a "cam roll over" effect.
Modifying the valve makes a hugh difference in conjunction with a brass FTP. The piston should be made out of metal imo.
AC customs valve mods and a AC brass piston and better orings will increase FPS
Adding the a longer barrel will literally floor your FPS numbers through the roof!
Quote from: airguns100 on February 08, 2011, 10:48:13 PM
Adding the a longer barrel will literally floor your FPS numbers through the roof!
Shouldn't that be "Adding the a longer barrel will literally
SHOOT your FPS numbers through the roof!"
Carl
I gained almost 100 fps with a 24" barrel.
Mike
I would not have expected that, but I guess it makes sense after thinking about it. Having a 24" barrel makes you not really have a pistol. What does the length, in most cases, of a barrel have to exceed in order for it to negatively effect FPS?
I'd like to keep mine as close to a pistol/handgun-ish state as possible...although I know it will have be be extended. What is the shortest length barrel that I can use and still keep the fps as high as possible? ---(flat top piston/valve,steel breech, all that stuff included)
Quote from: woody67 on February 09, 2011, 05:19:11 AM
I would not have expected that, but I guess it makes sense after thinking about it. Having a 24" barrel makes you not really have a pistol. What does the length, in most cases, of a barrel have to exceed in order for it to negatively effect FPS?
I'd like to keep mine as close to a pistol/handgun-ish state as possible...although I know it will have be be extended. What is the shortest length barrel that I can use and still keep the fps as high as possible? ---(flat top piston/valve,steel breech, all that stuff included)
Part of that depends on whether you are using CO2 or HPA.
I really think what you are asking is more of a personal thing than anything else. Sure there are some basic guidelines but each person usually has some requirements that dictates where they go in modifying their gun. A 14" barrel is going to be pretty much the max for a pistol, and it then sort of becomes a 'Buntline' or 'Joker' special. 10" or 12" is more realistic for a pistol.
Carl
Quote from: Mike on February 08, 2011, 10:09:30 PM
[youtube]https://www.youtube.com/watch?v=uIIG-aa3VrM#]1377 piston and valve mods[/url] This might help !
Mike
Great video...that was very helpful. I am going to order my valve/piston from AC. I'm also looking for a steel breech where I can have the bolt on the left side of the gun. I think I saw one, I just can't remember where.
Im glad it helped you,im no pro but i try to help some way.
Mike
I have found that 18 inches give the same fps as 24 and 14 inches is not a whole lot slower 10 to15 fps is all. I find the 18 inch barrel to be a bit of a pain to pack around and don't really like more than 12 inch barrel on a pistol. Go with 14 in 177 cal. and you will get the best fps and accuacy.
Quote from: Plasticman on February 09, 2011, 07:36:46 PM
I have found that 18 inches give the same fps as 24 and 14 inches is not a whole lot slower 10 to15 fps is all.
Carl.
This is something i hear on the yellow and the green all the time. My point proven ;D
Quote from: quickster47 on February 08, 2011, 10:51:02 PM
"Adding the a longer barrel will literally SHOOT your FPS numbers through the roof!"
Carl
i was thinking about using the word "shoot" but i thought it might give some people bad idea's ;D :P
I gained almost 56fps with the flat top piston.
And another 100fps with a 24 inch barrel.
It was well worth the money in my opinion.
Thanks
Ray
Quote from: woody67 on February 08, 2011, 09:37:35 PM
What do flat pistons and valves do for a 1377? Do they give the gun more power?
Not more power per se. But improves efficiency, when the OEM cup seal on the piston meets the valve, there is "dead space" or air that is not pushed into the valve. Some just reface the cone part of the valve, but I guess it's easier to just go flat. Flat top pistons need more lubrication from what I've read.
Saico, you mean like the 5 min reface and less than $5 spent to gain
70 fps at 10 pumps on my otherwise stock 1377 ?
http://www.crosman-air-pistol-owners-forum.com/board/index.php?topic=3688.0 (http://www.crosman-air-pistol-owners-forum.com/board/index.php?topic=3688.0)
Quote from: Daysailer on May 27, 2011, 03:11:49 PM
Saico, you mean like the 5 min reface and less than $5 spent to gain
70 fps at 10 pumps on my otherwise stock 1377 ?
http://www.crosman-air-pistol-owners-forum.com/board/index.php?topic=3688.0 (http://www.crosman-air-pistol-owners-forum.com/board/index.php?topic=3688.0)
Aye! I've always pondered the "solution" of ft valves and pistons. Different strokes, I guess, lulz. I think if I did that drill bit mod, instead of buying an adjustable piston, my pistol would be a lil lighter. BUT I still have a cup seal, not an FT.
The advantage of the FT piston/valve is the reduction of headspace losses, where all the air pumped
does not get into the valve.
When doing the valve cone slight trim, the headspace losses of the cup/cone systems is also
eliminated. see pictures :
http://www.network54.com/Forum/275684/thread/1211140448/1211339438/some+interesting+valve+stuff+for+pumpers+%28Pics%29 (http://www.network54.com/Forum/275684/thread/1211140448/1211339438/some+interesting+valve+stuff+for+pumpers+%28Pics%29)
By filing about .040" off of the tip of the valve cone, the misfit cup/cone is corrected.
Add a washer to the cup holder and an 0-ring to shim as shown in my thead, and all of the
advantages of Flattopping is realized up to about 8-10 pumps, and I have can buy more pellets.
Nope, not how I see it. You don't quite gain as musch as a Flat top. Think about it. When you flat top piston and valve, you gain the amount (length) of the cone on your pump stoke.....which equals more air per pump pushed into the valve. right?
More air = more power if you follow up at the other end of the valve to release it efficiently. That's what I'm thinking.
Rich
nope, you need to l e n g t h e n the piston to accommodate for the space of the cone or else you will still have headspace (the length of the cone).some folks think that a cone piston can be as effecient as a flat top but i have had a alloy (solid) piston ,an adjustable piston (both cones) and a flat top piston .the flat top would cause valve lock at 30 pumps where as the other two it wasn't happening
ark and eric,
Both good points about the cone tunnel headspace. There are threads here and on
the Crosman Forum that also discuss that issue. Some posters have reduced that tiny amount
headspace by reducing the inside diameter of the port. The proof for me is the pump
handle rebound from the unstored headspace air when cracking open the handle.
I am now getting 3.5" less rebound caused by unstored, headspace air.
I am not trying to say the method I am trying is ultimately better than a properly
adjusted, and quad ringed FT set up. However I am very surprised
how much improvement can be gained with the cup/cone, and stiffend stock piston.
I am just trying to point out another, seemingly lost, idea on how to also improve the
pump/valve system with fewer $$$ spent.
I value your helpful input. Tks
Quote from: Daysailer on May 28, 2011, 06:43:12 AM
ark and eric,
Both good points about the cone tunnel headspace. There are threads here and on
the Crosman Forum that also discuss that issue. Some posters have reduced that tiny amount
headspace by reducing the inside diameter of the port. The proof for me is the pump
handle rebound from the unstored headspace air when cracking open the handle.
I am now getting 3.5" less rebound caused by
I am not trying to say the method I am trying is ultimately better than a properly
adjusted, and quad ringed FT set up. However I am very surprised
how much improvement can be gained with the cup/cone, and stiffend stock piston.
I am just trying to point out another, seemingly lost, idea on how to also improve the
pump/valve system with fewer $$$ spent.
I value your helpful input. Tks
Don't get me wrong, your method is a fantastic mod, no doubt about it. For me, with access to a lathe and mill, it seems like more work than making the Flat-top piston and facing off the valve. Maybe not, but it seems like it. I guess I'm a FT snob :P ;)
I don't even own a chrony yet, but I can tell you that the difference between stock and FT is huge and very noticeable. I'm thinking that with the gain you acheived, that you really don;t need a chrony to see and feel the difference either??
Rich
Without the Chrony, the only difference I would notice is the change in
holdover for my longer pinking ranges. And that would take a while to
prove with my questionable skills ;) I do notice a bit more penetration
in my duct seal indoor trap too. Chrony really helps with solid proveable info.
With my 1st round of changes, piston stiffening, valve refit, and moving the
trigger spring to the valve, (read it recommended here somewhere) the 1377
pumped harder but chrony'd about 10fps lost. I was bummed.
When I went back in and put a hardware store lighter spring in the valve,
it pumped half as hard and gained 20 fps. Got the rest of the gain when
with the other mods listed on my post.
Without the Chrony, I may have believed the power was up, from the harder
pumping supposedly getting more air in. Turned out the opposite was true.
Wish I had your tools and skills with them, I would agree your method would be
easier. But I am a hand tool + dremel wizard at making 'one-off' parts for
my sailboats and other mods in my hobbies. So my efforts here have been to
see how much can be done with the least. The Mellon and AC FT stuff is really
inexpensive enough to be affortable, and would deliver known improvments.
But my need to reinvent the hexagon wheel drives me to satisfy my maddness...
... ( i guess buying a Chrony and going cheap on parts is a bit 'out-there' huh ??? )