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m102404 · March 5th, 2008, 07:43

If you can compare the over all lengths of stock TM piston to the overall length of the piston+piston head combo you're using, you might find that your combo length is anywhere from 0.5-1.5mm too short. If that was the case, tooth #1 (from the back, open end of the piston) would sit too far forward and the sector gear would come up and mash it, teeth #2 and #3 (etc) would be out of whack as well.

That happened on a couple of pistons I had, I used a washer to build up the space.

From face of piston head to base of piston, measured with a micrometer:
Stock TM - 73.95mm
Stock CA - 73.15mm
Stock JG (v2 I think) 74.72mm

The deepfire piston and modify piston head combo that I use is in a rifle at the moment. First setup "normally", I shredded a piston almost immediately. Second setup (new but same parts) I compared to the TM piston. I remember that it was shorted than the CA one (but not the exact ammount, sorry). One washer, about 1mm I think?, was enough to bring it up to the stock TM length. It's had about 1000 rounds through it now...zero wear, running with a 9.6v, EG1000 motor, 300fps spring.

The other deepfire piston I used was attached systema silent piston/cylinder head combo. Because of the shape of the piston head, it couldn't get a measurement of it's OAL. So I indexed off the back of the piston when the piston is at rest (like Illusion describes) and compared it to the stock TM piston. I think that it was a hair shorter than the stock TM. It's had over 4000 rounds through it, 9.6v battery, Systema magnum motor, deepfire mosfet and 300fps spring (crazy ROF...just for fun). I took it apart 3 days ago to take the mosfet out and there's just the slightest wear on the first tooth (just a rub on the edge where the sector gear hits it).

I hope that helps, I probably butchered the description (no morning coffee yet).

Tys

March 5th, 2008, 07:43	#10
m102404 Tys Trader rating Join Date: Apr 2006 Location: Toronto	If you can compare the over all lengths of stock TM piston to the overall length of the piston+piston head combo you're using, you might find that your combo length is anywhere from 0.5-1.5mm too short. If that was the case, tooth #1 (from the back, open end of the piston) would sit too far forward and the sector gear would come up and mash it, teeth #2 and #3 (etc) would be out of whack as well. That happened on a couple of pistons I had, I used a washer to build up the space. From face of piston head to base of piston, measured with a micrometer: Stock TM - 73.95mm Stock CA - 73.15mm Stock JG (v2 I think) 74.72mm The deepfire piston and modify piston head combo that I use is in a rifle at the moment. First setup "normally", I shredded a piston almost immediately. Second setup (new but same parts) I compared to the TM piston. I remember that it was shorted than the CA one (but not the exact ammount, sorry). One washer, about 1mm I think?, was enough to bring it up to the stock TM length. It's had about 1000 rounds through it now...zero wear, running with a 9.6v, EG1000 motor, 300fps spring. The other deepfire piston I used was attached systema silent piston/cylinder head combo. Because of the shape of the piston head, it couldn't get a measurement of it's OAL. So I indexed off the back of the piston when the piston is at rest (like Illusion describes) and compared it to the stock TM piston. I think that it was a hair shorter than the stock TM. It's had over 4000 rounds through it, 9.6v battery, Systema magnum motor, deepfire mosfet and 300fps spring (crazy ROF...just for fun). I took it apart 3 days ago to take the mosfet out and there's just the slightest wear on the first tooth (just a rub on the edge where the sector gear hits it). I hope that helps, I probably butchered the description (no morning coffee yet). Tys Last edited by m102404; March 5th, 2008 at 07:45..