Crosman Town & Country 107

[junglie]

The forearm lever is still droopy hehe.
Tonight I finally had some time to work on the 107 again, after all the Christmas parties.
I have the (man?) flu, so I will have plenty of airgun tinkering time

Right, I tested several pump rod length settings.
Greater length, even past the point where the air hole "works", still wouldn't cause over toggling.
Whilst closing the pump arm, I could still see movement of the pump rod, which I think means that it hadn't hit the valve wall yet.
When there's no air in the valve, the pump doesn't stay in place.
After 1 pump, with the gun being cocked (so that air stays in the valve), the pump arm does actually stay in place.
Is the air bubble in front of the pump cup giving the required contra pressure for over toggling to happen?
I also wondered if there might have been a ring in front of the valve wall, when the gun was built? A ring that makes contact with the pump cup, so that over toggling takes place? I don't know.

What I do know is that the maximum velocity that I found previously, 545 ft/s with 8 pumps, is the maximum velocity that I have found today too. Exactly 545 ft/s again. Will try lapping the probe at some point. For now I'm ok with the droopy lever, it doesn't affect my masculinity too much
One last question that I have: in the pump arm assy, there is a spring. Does the strength of this spring have any effect on the pump arm closing ability?

Oh, in DT Fletcher's book "The Literature of Crosman", there are some great photos of T&C ads and of General Hinds and Mr. P. Y. Hahn looking at the new T&C rifle.
I'm not sure if I may share them on here though.

It's good practice to store pump guns with a pump or two in to preserve the valves from the ingress of dust so that would keep your droopy arm closed.

[jirushi]

an easy way to rough set the piston so it cams over is to get a bit of 1/2" dowell or rod and in sert it down the compression tube till it hits the valve
then mark the rod through the lever pivot pin hole
once removed fit the piston to the rod line the pivot pin hole up on the rod and lever and adjust the piston till it's flush with the end of the rod or a mm longer to allow for wear in the linkages
tis will give you a starting point
another tip is to use a 3/16" punch in place of the roll pin
the spring steel in the lever is designed to keep the lever up with no air pressure and was later swapped to a plastic button in the lever that used friction between the two parts of the lever
Sheridan and Benjamin kept using the spring steel in the lever as they stopped using an adjustable piston rod in the early 60's(sheridans not sure on date for when Benjamin did)

Hi ped, thank you for this excellent advice.
Very useful.
I will do this.
I'll wait for my pump rod from JG Airguns to arrive first.
It's still strange that I didn't feel the pump cup hitting the valve when I adjusted the pump rod to maximum length. Or I missed it.
We'll see.
I do believe that the fact that my pump arm drops down when there is no pressure in the valve, is caused by a worn spring steel in the lever.
So further pump rod adjustments will be aimed at getting more efficiency (power).

@junglie, thank you. In the case of this 107, I would not like to store it with air in the valve, because the hammerspring needs to be tensioned (the gun cocked) to do so.
In the uncocked state, the hammer presses against the exhaust valve, and air simply escapes through the barrel when pumping.
I think the best way to maintain guns like the 107 and 108, is to shoot them regularly.
On the other hand, as 45flint pointed out earlier, a reason for this 107's relatively good survival might be the fact that it didn't work!

[45flint]

@junglie, thank you. In the case of this 107, I would not like to store it with air in the valve, because the hammerspring needs to be tensioned (the gun cocked) to do so.
In the uncocked state, the hammer presses against the exhaust valve, and air simply escapes through the barrel when pumping.
I think the best way to maintain guns like the 107 and 108, is to shoot them regularly.
On the other hand, as 45flint pointed out earlier, a reason for this 107's relatively good survival might be the fact that it didn't work!

Actually you can leave a couple pumps in to store your 107. I cock my bolt, put two pumps in, then holding the bolt I pull the trigger and slowly lower the bolt. It will rest on valve and not trip it. Mine stores those two pumps indefinitely.

[jirushi]

Actually you can leave a couple pumps in to store your 107. I cock my bolt, put two pumps in, then holding the bolt I pull the trigger and slowly lower the bolt. It will rest on valve and not trip it. Mine stores those two pumps indefinitely.

That's a great tip. Didn't know that. Will do.

[AllanM]

I have a Crosman 147 which (unlike my Benjamins and Sheridans) cocks automatically when pumped -- should I be leaving it "empty" when storing it?

[jirushi]

I have a Crosman 147 which (unlike my Benjamins and Sheridans) cocks automatically when pumped -- should I be leaving it "empty" when storing it?

I think I know the answer: not to worry.
The 147 doesn't have a hammer spring, iirc.
Pulling the trigger actually opens the valve.
That's why more pumps means a heavier trigger.

[AllanM]

Thanks Louis, that's put my mind at rest.

[--ped--]

the dump valve guns are best stored empty from a piece I read as generally the charge sneaks past the quad seal-not 100% sure on this myself but I tend to cycle my 130's/1300's - 140's and my 760 once every month same as I do my firebird and spitfire
I have a bam b45-3 and have left that charged for long periods along with sharp innova's and ace's but they use a moving sealing pin unlike the crosman's that uses a sealing cap

[jirushi]

That's good to know Ped. You have reminded me to fire my Spitfire and Firebird

By the way is there a particular brand of lapping paste that you could recommend for the 107 probe?
It must be fine. I suppose that autosol polishing paste is something totally different?

[--ped--]

stuff I have is at least 30yrs old I bought when I rebuilt a 21/4 s111 landy engine
any automotive valve grinding paste will do

[jirushi]

As per my post in the general section: the 107 is probably working better than new since yesterday, thanks to Ped's skills and knowledge.
Amazing. Ok, it's not the most efficient pumper. But 11.1 ft/lbs at 12 easy pumps ain't bad either for a .177 from 1948/49.
If only DT Fletcher could read that I have finally managed to solve the droopy pump arm issue lol (RIP).
It was down to a badly worn pump arm link pin hole and pin.
To up power, I tried a new pump cup and a leather pump seal from JG Airguns, both to no avail.
In came Ped with this double o-ring'd pump head. And an o-ring'd pellet probe.
It was a bit tricky to find the exact correct pump rod length. Now it cams over nicely.
Result.

[b.b]

Great read....