Quote:
Originally Posted by M.Garcia
What do you mean by "Blueprint" the upper gearbox?
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It means making every part in something perfect size, finish, fit, to what the drawing (blueprint) says...
On a ICS M4 split gearbox!the two halves of the upper gearbox castings are a bit crude.. ruff
Two problems
1) The ruff surface or the casting literally grinds the piston and the particules contaminate the whole gearbox (remember that sandpaper is grit glued to a sheet of paper... if you put the grit in grease... it's still sandpaper!!!)
So by doing that you actually reduce piston, gear, seal and cylinder wear drasticaly plus you (IF you polish the whole gearbox) eliminate most stress risers (crack will developpe in those imperfections) think sheet of paper with a small tear in it, if you pull that is were it will fail (tear up)
2) that friction slows down mouvement (piston and nosle plate) makes it harder for the gears and motor.... plus slows down stroke
((smoother cycle = more FPS, faster ROF and less wear obviously))
PLUS your upper gearbox looks like a millions bucks
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So what you do is you disassemble your upper and you prep the piston guiding tracks ( clean the halves with a toothbrush and liquid dish detergeant in a warm bath)
a) with a wet 600 paper and the proper tickness solid block you run the paper up and down the valley until all asperities are gone. (sharp corner too)
Note: If the paper doesnt have solid (hard) backing) it will smooth the whole area WITH the bump still in it ((take has little of has you can)) if you cant feel it with your finger... it's not going to slow down anything much
b) Using metal polish (I LOVE autosol) (on Q-Tips and/or shaped toilet paper) complete channel polishing
c) do the area were the nosel plate grinds
optional d) do the whole int/ext bit because now you've become obscessive compulsive
e) when you regrease use synthetic teflon grease ((has little has necessary))
People put to much grease because they think if's better an end up gunking up the whole thing
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Every 50000 bb's (in clean none desert condition) crack the upper gearbox open, clean (dish liquid again) check piston condition remove o-ring (on piston head) and decontaminate o-ring (LDD again) plus a bit of rubbing with a coton cloth , replace if condition is altered
Remember that sand will find it's way into a SCELLED gearbox so if you play in a sand box... guess what your doing that night!!!
Check cylinder ((if it's brass) and you feel weard things (very... no extremely politely repolish the inside with autosol (metal polish)
PS you can renew the exteror shine with brazo metal polish also
reclean with LDD dry with clean coton rag, remove dust, regrease inside out and store in a ziplock bag until reinstallation
If your cylinder is chrome or stainless it shouldnt have that much wear, if so use Autosol (metal polish) here too
Beware that if you polish the cylinder to much at some point you will lose compression (( bare in mind that clean well lubricated o-ring and piston is the secret to minimal cylinder wear.
Questions, comments... insults
Cheers
Pete