Post by Snarf on Apr 28, 2014 15:54:40 GMT -5
Hi all, it's Snarf again with some gearbox questions.
I somewhat recently got an Echo 1 SCAR L boneyard gun, and I opened up the gearbox to see what it needed. Everything was there, minus the wiring harness and a bushing, which I replaced. It's not in firing condition yet, but I'm about to buy a set of upgrade/replacement parts to finish it off. I just have a couple of questions for the more experienced techs (this is my first ever build).
The first problem involves compression. I started to test the compression just by pushing the piston into the cylinder, and it was AWFUL. The piston slid in with minimal air resistance and I just hear air rushing out from the cylinder head. After lubing up the cylinder head O-ring and the piston O-ring with silicon oil the compression was much improved, but still no where near the perfect compression of my SCAR H (thanks T6!) which I also had out and disassembled for comparison. I found that the only air leak I had was the cylinder head to air nozzle seal, which was less than ideal at all points in the cycle. I was going to ask you guys if an M4 air nozzle would be compatible with the SCAR L, because I could buy one with inner o-rings, but they're so overpriced that I want to ask about any DIY mods for compression first.
The other thing is I also switched some of the components from the SCAR H gearbox to the SCAR L, because the L is going to become my primary once it's finished, and the SCAR H had a far nicer gearbox. Specifically, I switched the spring guide (H had bearings, L did not), bushings (copper to oiled steel), and the tappet plate (bendy plastic to stiffer polycarb). I'm worried about the tappet plate swap, because the H had a slightly different shape to it than the L, and the sector gear on the H had some plastic around it kind of like a small sector gear clip, probably for feeding issues arising from the extra long air nozzle or something. I haven't fired the H yet because it needs new connectors/wiring at the moment but we'll see. Do you think it'll be a problem?
I'm not asking for a complete guide or a parts list, but if anyone is familiar with the SCAR L or first builds in general I'd appreciate any tips. Thanks.
I somewhat recently got an Echo 1 SCAR L boneyard gun, and I opened up the gearbox to see what it needed. Everything was there, minus the wiring harness and a bushing, which I replaced. It's not in firing condition yet, but I'm about to buy a set of upgrade/replacement parts to finish it off. I just have a couple of questions for the more experienced techs (this is my first ever build).
The first problem involves compression. I started to test the compression just by pushing the piston into the cylinder, and it was AWFUL. The piston slid in with minimal air resistance and I just hear air rushing out from the cylinder head. After lubing up the cylinder head O-ring and the piston O-ring with silicon oil the compression was much improved, but still no where near the perfect compression of my SCAR H (thanks T6!) which I also had out and disassembled for comparison. I found that the only air leak I had was the cylinder head to air nozzle seal, which was less than ideal at all points in the cycle. I was going to ask you guys if an M4 air nozzle would be compatible with the SCAR L, because I could buy one with inner o-rings, but they're so overpriced that I want to ask about any DIY mods for compression first.
The other thing is I also switched some of the components from the SCAR H gearbox to the SCAR L, because the L is going to become my primary once it's finished, and the SCAR H had a far nicer gearbox. Specifically, I switched the spring guide (H had bearings, L did not), bushings (copper to oiled steel), and the tappet plate (bendy plastic to stiffer polycarb). I'm worried about the tappet plate swap, because the H had a slightly different shape to it than the L, and the sector gear on the H had some plastic around it kind of like a small sector gear clip, probably for feeding issues arising from the extra long air nozzle or something. I haven't fired the H yet because it needs new connectors/wiring at the moment but we'll see. Do you think it'll be a problem?
I'm not asking for a complete guide or a parts list, but if anyone is familiar with the SCAR L or first builds in general I'd appreciate any tips. Thanks.
