Short stroking experimenting


This weekends tinkering - short stroking! On my std slr after upgrades- m100 18:1 shs gears, 41000k motor, it was going fine, then I went 13:1 and I was getting some pre engagement issues and my piston was occasionally getting completely jammed. So decided to give short stroking a go! Watched a few videos and just decided to go for it and if I ruin anything I’ll just get more. Took 2 teeth of the piston, and then even though most the the videos said front teeth of the gears (lite operating group said back) I went the back teeth as it was the last few causing my piston to jam. After lots of back and fourth, closing the gear box testing, opening up again, removing another gear tooth, test, repeat I ended up taking 4 off the back and just 2 off the ladder to clear enough room for the position not to jam. Now I was awear removing the back teeth might cause timing issues, but it runs quite well now and sounds so much cleaner and crisper than it did before and fires perfect. So I guess my question / discussion is, how did removing the back 4 teeth be fine when every one said it that it wouldn’t lol ? Because surly taking off the front 4 teeth would have changed the pick up timing too ? ( a Delay chip then? I don’t have one of those) Haven’t tested fps yet but was getting 350-400 before and I’m guessing it’s equal to a rough 80% port now with where the piston head position is. And yes theres some teeth now in the ladder not being used. What’s other peoples experiences with removing pick up or back teeth ?

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The M100 isn’t strong enough to prevent PME caused by the high speed motor and high speed gears. Removing 4 teeth from the back and releasing much earlier you’ve also shortened the distance the piston has to travel forward, at a cost of ~50fps. At least.

Short stroking from the pick up side of the sector and release side of the piston is useful when trying to maintain the original tappet/nozzle timing.
I’ll short stroke gears to correct feeding or air seal issue in high speed builds by offsetting the nozzle/tappet timing.

Why removing the same number of teeth from both is important


Yes that goal aswell too lose fps to make it more field legal, get it down to the 300 range.

I’ll chrono it tomorrow see where I’m at, but I can definitely feel a difference.

And I’ll check Aoe too but it does sound crisper so I think it’s ok for the moment.

Yep just chrono’d with old milkies 300fps, but I normally run aks. That’s pretty much what I wanted out of it. Now filed legal. Not bad for some guess work with removing teeth and where the piston head now sits.

300FPS on full auto?
You might have snagged it first time then.