OG mini cocker cycling issues

[Drcemento]

An old friend handed over a Minicocker he picked up about 10 years ago SN# 3021 and asked if I could bring it back to life. I've built 3 cockers now and each has its own set of issues that seam to end in a forum post. This ones no different.
The marker:
completely stock - old style LPR, C clip 3 way and sheridan sprung.

what i've done - total breakdown and rebuild including LPR, ram and 3 way. cleaned everything and greased/lubed it all based on PB teks great little videos. set it up based on KC cocker docs videos. both of which have led to successful builds

it airs up with no leaks and cycles but the ram is not pushing the cocking rod back far enough to catch the sear. I'm using unregged Co2 in the vertical ASA for quick testing.
I've adjusted the LPR up and down from the initial point of 1 3/4 turns in from flush to see if it just needed some more pressure - that did nothing. the ram needs almost another full 1/4" of travel to push it back enough to catch the sear.

all the parts and pieces seam to be the correct length for that model of cocker - ive screwed with the trigger rod/ 3way adjuster as well with no change - if I manually pull rear block back and cock it it fires at a good velocity.

as always thanks in advance for your help. will post some pics - its a great looking classic cocker.

[RuleOfSines]

You're able to pull the backblock back far enough while it is still attached to the ram? So the ram appears to have some more travel in it?

Are you able to easily push the backblock forward while holding the trigger? How old are we talking with the LPR? Narrow brass one?

[Drcemento]

ram has the travel for sure - can pull back and cock it while attached

aired up with the trigger pulled I can push the back block in and out - not super easily - its spongy.

rams a 3 piece ram not super old or odd for that time period

[Drcemento]

heres the marker in question...

[OpusX]

Unscrew the cocking rod from the ram shaft a bit to give it more travel, while also taking that set screw out of the cocking rod and screwing in the cocking knob a bit.

[nak81783]

Adding to OpusX, make sure there is a small gap between body and back block when aired up. There are two reasons for this. You don’t want those pieces smacking together, and you don’t want to lose available ram stroke on the forward end just to keep two pieces touching that shouldn’t be. In other words, the threads (either end of pump rod) shouldn’t be under tension when the marker is aired up at rest (bolt closed).

If OpusX’s suggestion doesn’t fully solve the issue, can you confirm the trigger plate is slotted? I preferred slotted trigger plates on everything, but it’s definitely required on the c-clip 3-ways to give the trigger time to return to a position where it can catch the sear before the 3-way actuates the ram forward.

That said, try protruding the sear out of the hammer a bit more. The timing could be off, allowing the sear to not catch/skip.

[Drcemento]

The pump arm and block is adjusted so the block won’t slap the back. don’t think I can get more travel out of it. I’ve also adjusted the cocking rod so the bolt is just past the feed opening when cocked.

trigger plate is slotted. Will play with the sear and 3 way way a little more. Will also double check lpr redbuild and see if I got it wrong…

[Drcemento]

got out the ruler to look at ram travel. if I take the cocking rod and bolt out, air up and pull the trigger back the ram extends the front of the back block 1 1/8" from the back of the body.

de-gassed with the bolt and cocking rod back on the front of the back block is 7/8" from the back of the body in the cocked position

gas it up and pull the trigger back with the bolt and the cocking rod back in the space is only 5/8" of an inch - exactly the spot where it the cocking rod starts to get hard to pull back due to the spring its pulling against

i suspect the ram does not have enough force to push it the cocking rod back against that stiff sheridan spring. - I have to give it a good pull to do it myself

that said the ram should have enough pressure to do this.....

[OpusX]

i suspect the ram does not have enough force to push it the cocking rod back against that stiff sheridan spring. - I have to give it a good pull to do it myself

that said the ram should have enough pressure to do this.....

Totally possible, I've had such problems before. I typically try to respring if that is the issue, so I'm not putting hella force on all the bits, but if your sticking with Sheridan springs you can turn of the LPR a bit.

Even those old three piece LPRs are "adjustable". You have to remove the back section (which you should be able to do with it still on the marker, just remove the hose and unscrew the entire front two bits together) and look inside, there will be a screw to adjust. In for higher pressure, out for lower.

[Drcemento]

dialed that LPR through a full range of adjustment to no avail. double checked assembly to to see if I put it back together wrong .
have 2 others - one externally adjustable. will try them both. would like to make it work using original springing - stubborn male pride I guess. but i think i have a set of internals I can use, and plenty of springs laying around.

any other theories on what could affect ram pressure? 3 way not letting enough air through?

[Jordan]

It's possible your LPR just doesn't output enough, whether it's from worn springs or aged components.

Sheridan springing works fine... every Palmer's semi uses it, and I've never had issues with my vintage Cockers. It does require fairly high LPR pressure, though.

[Drcemento]

swapped out the LPR and bingo - cycled and fired - for a bit anyway. I'm sure I still have some time and plenty adjusting to do to get it all balanced and timed, but I think that was one step closer.