Recommended Cylinder Parts
 

I am having some compression problems on my ICS M4 SIR and was wondering what parts you guys and gals would recommend me replacing them with.

What brands to look at and which ones to stay away from.

Or should i just get those ICS upper gearbox sets?

Thanks in advance for all the help.

it would help if you knew which parts were leaking.
Or you can get a modify cylinder, piston head, and cylinder head.

I don't really know what is leaking. i was just going to replace it all with better parts since i was doing one or two.

So i was looking for air nozzle, piston, piston head, cylinder, cylinder head, spring and spring guide.

or does anyone know how good of quality the whole upper gearbox upgrade is from ICS?

Always keep your compression parts all the same company to ensure compatibility. Some companies use different size pistons and cylinder heads.
systema, prometheus and guarder make good compression parts. systema and prometheus are interchangeable, guarder is not.

It's a good idea to have an extra upper for an ICS gun. That is what they are designed for. Then, with 2 different springs, you could have an indoor gun and an outdoor gun in one. However it is still worth your while to fix the upper that you do have. Check the orings in the piston head and cylinder head. Often a leaky cylinder head oring can be fixed with a little grease put around it ( it doesn't move after all). I think there is a way to check for nozzle/hop-up leaks by firing upside down??? Maybe someone else could say exactly what to do?? If it's parts are in good shape but you still cannot find the problem, then changing the nozzle, piston head, cylinder head and tappet plate should cover everything. If that doesn't fix it, check the hop-up.

If you've shot 20,000 or more with it then change spring and guide as well. Check gears and bushings as well. ICS anti-reversal lever springs are notoriously weak. If you can get one change it as well.

thanks for the info guys i appriciate it.

To check airseal turn the gun upside down with no magazine in it. place one bb in the feed tube. The nozzle is already in the hop bucking and a perfect airseal should not move the bb in feed tube. Fire once and if bb moves you found a problem, what component? Nozzle and/or hop. If its your piston head or cylinder head the fps is inconsistent, chrono to find that out.