Installing a new gas valve

CNC Warrior's new gas valve

Removing the existing gas valve
CNC Warrior surprised me today by sending me two gas valves for my Yugo. It didn't take long before I was pulling off the hand guard/gas tube assembly and pulling out the gas valve. The thumb switch and spring pops right out once the valve is centered and pulled partially out, then the existing valve slides right out.

Installing the new gas valve
Getting the new valve in wasn't quite as easy, but then it's new and not worn. How much bigger? I put a micrometer on the two and here's the results (Old vs New):
Diameter: .549" / .5885"
OA Length: .921" / .9215"
Barrel length: .815" / .820"
Dia. of end that slides into gas tube: .508" / .506"

Tapping in the new gas valve
As you can see, the two are very close in size, the new valve being a bit bigger. That tiny increase in size makes for a very tight fit. When the new valve is slid into the gas vent housing, it stops around the hole in the gas valve. I'm guessing there's a tiny shaving of metal in the interior of the barrel that hangs up the tighter fitting valve. I carefully tapped the base of the valve with a rubber mallet, then nudged it out by putting a screwdriver blade in from of the valve, pushing it out. After doing this 3 or 4 times the valve slid much easier. I was then able to push the valve in, and rotate it to the right to lock it into its correct position. It's tight, but then it's supposed to be. I'll be bringing the mallet and screwdriver to the range with me until it's broken in, just in case the valve needs to be rotated or removed. I have no doubt this valve is going to seal tightly. I'll give you a report on it the next time I shoot and remove it for cleaning. Thanks again CNC Warrior. Here's a link to their web page: www.cncwarrior.com

Click HERE to see a post I put up on CNC Warrior's gas valves 3 years ago.

AN IMPORTANT NOTE ON CLEANING

As some of you may know, I was a Navy Seabee and after we fired our M-16's, the battalion always scrubbed their weapons thoroughly in a trough of solvent, then hosed them down with cans of WD-40. I still sometimes follow that routine to some extent, but it's not the best idea, especially when shooting military surplus ammo. WD-40 is an very good solvent, and I've always liked the idea that I could spray a hi-pressure stream into hard to reach places. The problem is that it's a penetrating oil and I've heard it contains of a high percentage of kerosene (though I can't find that info anywhere, including the 'Material Safety Data Sheet').

"....the last thing I need when lives are on the line is dead ammo..."

Kerosene can break down the waterproofing that seals military ammo, contaminating primers and powder. It's funny, but I've been using WD-40 for about 40 years, and I've never had an issue like this. The possibility does make me think twice about using it in any weapon that I use for home and personal defense, because the last thing I need when lives are on the line is dead ammo. On my range rifles it's not that important, and it does do a great job cleaning as well as being relatively inexpensive. If you do use it, be sure to completely dry off your firearm prior to reassembly. I'm guessing that the military wised up about this some time ago... at least I hope so.