Things one should know about the Classic Army SCAR internals....

[CDN_Stalker]

********* Admin, I originally spent a good 15 mins typing this out to post in the Doctor's Corner, when I tried to post it I had to log in again, and again, and again, and was denied access to posting in the Doctor's Corner, so I am posting it here to get it out. Please move to the correct section if this thread gets accepted. Thanks.*****************





Since I have a "less than 800 rounds and the bevel gear lost it's teeth" SCAR on my bench right now and I got the mechbox fully together, shimmed, etc. here are my observations since I'm one of the few, if not the first, to work on it's internals. It's a Version 2 mechbox, but some things you should know:

* Comes stock with a ribbed cylinder, similar to the G&P guns.

* Comes with a bearing spring guide already.

* Still comes with the crappy yellow plastic CA piston body people love to hate because it's crap (BTW, this one has wear on the teeth, most likely due to manufacturing burrs on the sector gear.)

* Piston head is aluminum, ported (has holes in the face, forward motion when pushed past the port on the cylinder inflates the O-ring and provides very good seal) type. Also, it is a partial type bearing pistonhead, in that it has the bearing ring as well as one washer that presses against the spring. Good news is, you use a #2 Phillips screwdriver to undo the head, unlike that little fucker of a fibre nut that came in other CA guns I've worked on.

* Bevel gear is of the 4 notch type.

Now, since the gears needed to be replaced, I suggested the piston be replaced as well. Thanks to Testtube having a problem M4A1 "Franken gun" and donating ICS gears and an ICS piston/head, here is what I've found:

* Spur gear and sector gear had zero problems fitting into the 7mm bearing bushings, but the shaft on both sides of the bevel gear were a very tight fit, enough to cause major problems when I was shimming (incidentally, the bevel gear required no shims whatsoever, which in the aformentioned case, was a GOOD thing!) I actually had to use my flush cutting wire cutters and a small jewellers slotted screwdriver to get the bushings off the gear.

* Neither the ICS piston head, nor the stock TM piston heads I tried would give any compression in the cylinder at all. I ended up using the stock CA aluminum piston head on the ICS piston body, compression is great now.

* Regarding the bevel gear shaft size, I literally secured the gear into my drill press and used a fine diamond file to reduce the size a bit as well as taper the tip of the shaft. Both sides fit well now, and require just a little effort to remove. More an ICS gear problem than a CA bushing type problem.

* The nozzle is quite long, much longer than other V2 mechbox nozzles I've dealt with. I'd say it's about 1/8" to 1/4" longer than a typical M16/M4/MP5 nozzle. Case in point, if yo uwant to go to town in upgrading, pay attention to that, I haven't a clue what type of nozzle this gun requires.

I think that's all for now, will update later when I get more info to share.

~S~

[swatt13]

pics!?

[CDN_Stalker]

Sure, I can, but mind you, it's closed up right now and I sure heck don't want to screw with it by opening to take pics.

EDIT: Emperor Penguin posted this before I replied here, so I'm posting it here since it's more detailed than I could do.

http://www.airsoftextreme.com/store/...es&pages_id=42

[Ibby]

I don't think the ICS bevel gear is a problem. Those gears came out of one of my M4's, and they fit in the bushings of it and a couple other guns (including the Frankengun) just fine. Did it fit into the other bushings (the sector or spur gear)? Just a thought. I've changed bushings around for better fits before.
The drill machining is a nice touch. Welcome to the poor man's milling machine!
And as for taking shims off, a great tool I use is an exacto knife with 2 blades in it facing each other. Works great.

[CDN_Stalker]

I was lazy and didn't walk over to dig up my X-acto knife. And I think the prolem was the gear fitting into the 7mm bearing bushings since all that I tried out, both sides were having to be forced onto the bushing. So, I MADE them fit! Ya, drill or drillpress are great for dealing with round things that need to be brought donw a bit or even just evenly polished. Most creative I ever got was an electric drill holding a part that needed to be reduced in size (or shape, I've done this with steel pointy things like indent punches for drilling), hold the tip in the drill, then load a reinforced cut off wheel in the Dremel................ ya, get both to run in opposite directions, makes for beautifully even (and centered) points.

[EmperorPenguin]

I just finished putting it all back together, i happened to have a tm m4 mechbox on the bench too so i popped the nozzle out and measured the up, it's 1/4" shorter than the scar. http://picasaweb.google.com/RikyTic/20070404Scar I also decided to use something thin to place as shims on either side, but i used some of the thin covers you take out the back of your computer when you install a pci card, safer than getting a razor blade peice in the eye.

[ILLusion]

Bearings in general, I've found fit extremely tight on stock gears - almost to the point of being destructive. Try fitting Marui gears in to bearings, and you'll never be able to get them off again (assuming you managed to hammer them on without blowing the bearing apart.)

[CDN_Stalker]

Good to know. Thing is, I'm on rush mode to get this gun out by Friday and didn't have time to wait for bushings to come in.