IZH 46M malfunction

[rogersdan]

The seal on the IZH is weak, but this is a strange problem. I pump and charge the cylinder but there is no release of air when I pull the trigger - it's exactly like a dry fire - however if I immediately pump and charge the cylinder again, it fire normally. Any ideas on what the problem and solution might be?

Thanks, Dan

[PFribley]

Trigger adjustment???

[rogersdan]

What trigger adjustment are you suggesting? How would the trigger control the charging of the cylinder?

Thanks, Dan

[Houngan]

What trigger adjustment are you suggesting? How would the trigger control the charging of the cylinder?

Thanks, Dan

It sounds like short-stroking, when you don't quite get the hammer reset, but that comes with a noticeable whoosh of air escaping. Maybe a trigger adjustment that is letting the cocking mechanism fail the first time?

[kevinweiho]

I think the problem could be some rusty gunk in the valve mechanism or a deteriorated piston/valve seal.

Did you try manually lifting the breech block 90º (which closes the air valve and allows the pistol to be fully pressurized)
before cocking to see if it gives you the same problem, and have you oiled the piston seal and valve regularly?

[rogersdan]

Kevin,

Thanks for your suggestion, I think it has something to do with the breech block - which frequently does not stay open when I attempt to charge the cylinder. The breech block tends to flop down unless I hold it open - unfortunately holding it open does not necessarily allow me to charge the cylinder.

I haven't had the pistol apart - but if I begin disassembly, would it be obvious if the breech block is the problem?

Thanks, Dan

[Gwhite]

The inner workings of the IZH are a bit complex. I've dealt with several different issues over the years with the 15 pistols used by the collegiate team i help coach. I've attached the write-ups of what I found, which include some disassembly info, and diagrams of the inner workings of the firing seal system.

[rogersdan]

Gwhite,

Thanks so much for that detailed information! I actually had a stuck trigger a few years ago and fixed it with the help of your instructions; I think I can use the two files on the breech block to figure out my problem - if not Pilkguns will attempt a repair. Once again thanks - everybody with an Izzy should know about your instructions for repair.

Dan

[Gwhite]

Thanks! Glad you've found them useful.

There's more to come, but we've got enough working IZH's at the moment that repairs aren't a priority. The next big one is a firing seal replacement, and I will document it in a similar fashion. It takes about 3 times as long to photograph & document a repair as it does to just do it, so I need a good chunk of time & clear bench space to give it a go.

[rogersdan]

FYI,

There are quite a few IZZY parts - direct from Russia - on Ebay. This is the valve spring - #13 - but it looks a good bit longer than what you have pictured in your instructions. I have emailed the seller to clarify - but no response yet.

https://www.ebay.com/itm/IZH-46-46M-Ori ... SwWaRZqqqH

Dan

[m1963]

The OFAC sanctions against importation of IZH items into the US are still in place. None of these parts are worth going to prison:

https://www.treasury.gov/resource-cente ... raine.aspx

Stick with whatever EAA has left:

https://eaacorp.com/gun_accessories/ind ... 00346.html

[rogersdan]

Thanks - I had no idea!

[GKU]

I have the Breech Flopping Closed When Cooking issue with mines ...... thanks Gwhite for posting/giving the PDFs fixes !
Will the replacement of this Valve Spring - (#13) #300314 have an effect on the velocity ?
Also does anyone know the spec measurements of this spring ?

~ Thanks, GKU

[Gwhite]

I have the Breech Flopping Closed When Cooking issue with mines ...... thanks Gwhite for posting/giving the PDFs fixes !
Will the replacement of this Valve Spring - (#13) #300314 have an effect on the velocity ?
Also does anyone know the spec measurements of this spring ?

~ Thanks, GKU

The velocity is going to be determined by the charge of compressed air in the pump cylinder. Once the valve opens, it dumps that into the barrel. There might be a tiny effect from a stiffer spring opening the valve quicker, but I doubt you could measure it.

[GKU]

Thanks Gwhite for the quick reply !

~ GKU / Greg

[Gwhite]

I have the Breech Flopping Closed When Cooking issue with mines ...... thanks Gwhite for posting/giving the PDFs fixes !
Will the replacement of this Valve Spring - (#13) #300314 have an effect on the velocity ?
Also does anyone know the spec measurements of this spring ?

~ Thanks, GKU

I just measured several:

Length: 11.5 mm (0.453")
Outside Diameter: 4.70 mm (0.185")
Wire Diameter: 0.72 mm (0.0284")
Turns: ~ 5.5

There are 5 full turns, plus a little extra. The ends have the last turn closed up against the previous one & then ground flat. If the action is cocked when the pistol is stored, the spring can take a "set" over time, and compress:

[GKU]

Thanks Gwhite !

I removed and looked at my valve spring and it was very close to its factory spec.

I remove part #12 slide latch spring and cut off a couple of coils.
Bent coil closed up against the previous one and ground flat.
It's new OAL is now 24mm off it's original OAL of 34mm.

Breech Flopping Closed When Cooking use to occured about 50% of the times, now not even once yet.
I bought an extra slide latch spring just in case.

~ GKU

[Gwhite]

Thanks! That's good to know. I suspect a lot of the problems stem from a combination of marginal heat treating of the springs, and storing the pistols cocked and/or with the breech wide open.

[GKU]

I never stored my IZH cocked only with the breech latch open to help the 2 breech seals from compressing/deforming with long term compression.

Also, I was reluctant to add that I removed about a coil at a time or 5mm and retested.
All IZH I suppose will be a bit different so it might stop there ?

With my IZH it helped and improved from the 50% to about 80% of the times when cocking.
So I removed another 5mm to get 100% for the breech to stay in the open position after retuning the cocking arm to its closed position.

Far as I know this spring’s tension seems if to great will add/aid to the forward momentum on the breech arm when returning the cocking arm to the closed position. The faster one closes the more pronounce this effect becomes. I believe age and degrading tension on springs involved along with breaking in and smoothing out of parts can contribute to this imbalanced issue.

~ ATB, GKU