autococker cycles but won't fire sometimes

[rawbutter]

To preface, I know nothing about autocockers. But someone saw my SPAR valve and hired me to do a custom auto-response mod on an autococker that was previously set up for a pneu-cocker that looked a lot like this one. So, I tried to put a modified SPAR valve in there, but it didn't work. Then I tried something simpler...a swing-arm with a spring return that would hit the MSV-2 once on pull and once on release.


The swing-arm came out pretty well, complete with roller bearings.



Unfortunately, when I mounted the arm in the frame and got everything working right, I still had problems. It seems the gun like to fire on semi, and it will do auto-response if I shoot slowly. But if I try to shoot fast, it won't cycle reliably.

Anyone got any ideas why this is happening? Again, I know nothing about autocockers, so you're gonna have tell me more than "adjust the timing."

[madmar1009]

My 2 cents --- if your autococker is cycling, but not firing, then you need to increase the timing between your bolt release on your trigger and your recock. You can adjust the point at when the bolt sear gets tripped or the point at when the recock starts.

What to Adjust:

To time the marker you adjust two components of the pneumatics: the length of the searlug and the length of the timing rod. The searlug sticks down from the hammer, attached to the rear cocking rod, and is the component that is released from the sear when the trigger is decompressed, firing the marker. The timing rod is the linkage device that connects the three-way shaft (the rod inside the three-way) to the trigger. It actuates the three-way valve servo; it controls how long the two parts of the ram piston remain pressureized. Making the searlug stick out less will prevent it from ever hooking on the sear, producing the same result that would occur if you held the trigger down while cocking the rear cocking rod (when you pull the rod back and release it, it will spring back into the uncocked position). This is known as a farting Autococker because of the clapping noise it produces. If the searlug sticks out too far, the marker won't cock because you won't be able to pull the cocking rod back far enough for it to get over the sear (the sear will actually block the searlug from moving behind it).

Adjusting the timing rod so that it is too short will prevent the marker from firing because it will never allow the hammer to strike the valve (because the backblock recocks before it gets a chance to fire). If the timing rod is too long, however, it will not bring the cocking rod back fast enough for it to catch the sear when you release the trigger. You will also experiance problems due to the bolt not giving the paintballs much time to load (the bolt will recock late into the trigger pull). Keep in mind that adjustments to the timing rod depend on if you are using a slide trigger or a swing (hinge) trigger. If you have a swing trigger, just take the information above and reverse it, so if the timing rod is too long it will recock the marker before it fires, etc.

Some aftermarker three-way valves are also adjustable. If this is the case, then you can adjuse the three-way instead of the timing rod, which most would agree is easier to do because adjustments to the timing rod require you to use allen wrenches, whereas adjusting the three-way can be done with no tools.

http://www.zdspb.com/tech/misc/cockertiming.html

[Jordan]

Bump the LPR up a hair. Pneucockers live and die on LPR pressure, there's a lot going on and raising output pressure can bandaid a slow recharge.

[rawbutter]

Thanks, guys. I have already adjusted the hammer lug, so I think I'll try the LPR next. After that, I'll maybe mess with the timing. (That was a great write-up, Madmar.)

I should have said, however, that the marker was working fine before I started messing with it, so I'm hoping the timing doesn't need adjustment.

[the_hyren]

From the youtube video I can tell you why it only triggers semi. The return force of the valve is really low and it is not resetting fast enough. You need to find a way to add a return spring or run the valve at a full 125psi with a separate lpr.

Like a prior poster said. A cocker cycling but not firing is a timing issue. What happens is the back block catches the hammer before it makes contact with the valve. You need to change the 3way activation point so it occurs later.

Also possible the hammer never releases which means the lug is too far down.

If you put the frame on the body without it aired up and manually cock the hammer and then pull on the timing rod you can see where the hammer releases. Ideal spot is very early. Maybe a mm into motion.

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[Jordan]

One other thing to think about... Cockers do require a certain amount of time to complete a cycle. That AR setup may not work correctly over a certain trigger speed, even if you do get the MSV to reset faster.

[the_hyren]

One other thing to think about... Cockers do require a certain amount of time to complete a cycle. That AR setup may not work correctly over a certain trigger speed, even if you do get the MSV to reset faster.

Mine is good for about 18 before it becomes a blender

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[latches109]

This applies to a few specific use cases for high ROF -> Check the length of the hammer body is not interfering with the beavertail bolt, or not clearing the sear with full spring compression to the IVG. I have seen issues with longer bolts - e.g. CCM halfbock, ID halfblock - preventing the hammer sear from setting properly under rapid fire. I suspected this is why eblade hammers were shorter than stock. I have tested this quite a bit with high ROF eblades and found shorter hammers provided greater timing range.