Crosman 140

[Doc Sharptail]

This is one of the later versions with the up-graded trigger group.



Dunnville roll stamp:



Front sight:



Rear sight:



Those rear sight screw holes go all the way into the bore. I haven't benched it yet.

For those of you wondering why sometimes these won't cock properly, it's because the sear block gets installed backwards. The fix is simple.

This one still needs a bit of tlc to get it up to power. It's to the point where it will hold air, and it does 440-460 at five pumps, after a good clean 'n lube.

Ten pumps, and the velocity drops to 420-430, with the gun blasting air out through the trigger group opening. On my 13-XX's this behavior indicates valve stem troubles. On this I'm suspecting it would be the quad seal ?

I should have taken pics of the piston and valve face when I had it apart.

I'm still pretty happy with this latest acquisition. For a gun this old to be still throwing pellets down range without anything new being added to it is on the amazing side.....

Regards,

Doc Sharptail

[SeanMP]

Doc that's a beauty for sure.

Are you going to do a full restoration job on it?

[rsterne]

I love the old 140s.... they frequently have some beautiful wood hiding under the rather blah finish....

Bob

[Doc Sharptail]

It won't be for a while until I get to the wood and metal refinishing. I took the gun apart again tonight, and did a couple of minor replacements. The sear block spring and quad seal cup o-ring got replaced. I made up a poly tube transfer port for it. The two cemented together o-rings that were used as a seal were pretty flaked out.

The gun quit blowing air out the trigger group opening. 5 pumps now give me 460 fps. I'm still getting a velocity drop at 10 pumps- down to 430-440 fps. I'm probably going to have to think about this for a while.

Here's a look at the piston face:



And the valve face:



The valve looks just like a 13-XX valve on the front section. There's even a trigger guard screw hole on the side opposite the stock screw stud hole.

It looks like my repair options remaining are the following:

Go to a flat top piston.

Replace the valve check button and spring.

Replace the valve o-ring that goes over the threads on the body.

And replace the quad seal with a new one...

Regards,

Doc Sharptail

[SeanMP]

I've only ever seen one original.

It was similar in size and shape to the current transfer ports in 13xx,22xx but the rib in the center was thin and there was remnants of the usual flat rubber washer top and bottom.

Having said that there is no guarantee that was even "original" ...You know how it goes

I have a couple 140/1400's in for repair but they are at home and I'm on the ship, so it would be a few days before I could have a peek

[Doc Sharptail]

Thanks for the description Sean. It may be difficult coming up with a photo of an original.

I did check a SBK kit breech on it. The rear breech screw hole and transfer port holes line up, but not the front breech screw hole. There's potential there- if I want to do it. That's a decision that's going to require a bit of thought.... For the time being, I had better order in a small handful of the modern transfer ports, and make chips fly with the dremel and drill press

Regards,

Doc Sharptail

[rsterne]

I found the flat-top piston worked well.... I machined off the front retained for the cup, left the felt wiper in place, pressed on a new aluminum front section, turned it to length and turned an O-ring groove in it....



Bob

[Doc Sharptail]

I ftp'd it last night, and I'm floating. Huge improvement. I'm seeing upper 520's for 10 pumps with the 14.3 gr. Daisy h.p.'s. The gun hasn't been ported in any way, and my first polytube transfer port is a bit on the wonky side...

I'll get back to this with a few more pix later on, but for now, hi-ho, it's off to work I go :P

Regards,

Doc Sharptail

[rsterne]

I put a modern style transfer port in a 140.... The only critical issue is drilling the 0.200" ID recess in the barrel for the upper part of the transfer port to the correct depth to apply some compression on the lower seal without lifting the breech up.... Isn't the breech already drilled 1/4" right through?.... I thought it was....

Bob

[Doc Sharptail]

I put a modern style transfer port in a 140.... The only critical issue is drilling the 0.200" ID recess in the barrel for the upper part of the transfer port to the correct depth to apply some compression on the lower seal without lifting the breech up.... Isn't the breech already drilled 1/4" right through?.... I thought it was....

Bob

It's a bit less than 0.25", and quite elliptical :P I should put my 1/4" mill cutter to work on it.

How hard is it seperating bbl and breech on these? There's a hefty burr holding the 2 together on this gun. Hopefully I'll be able to drift them apart without laying too much of a beating on the bbl shank...

Regards,

Doc Sharptail