Questions about cylinders and pistons

[Lizander]

Alright, I want to upgrade my ak47, which is actually just a kraken >.< but any ways I've been looking around for a new piston, piston head and cylinder, but I have noticed that some pistons have teeth all the way up the body of the piston, while some are only half way along the body, and some have no teeth. What are the differences between these other than the teeth? Does it matter what kind of coating or material the cylinders are made of? Do the different parts I have listed have to be the same make or manufacture? Does a sorbo pad on top of the piston head add any extra length I need to be carefull with? Why is it, with some piston heads, there are bearings, while with others, there aren't? What are some good names for these parts?

If you can answer any or all of my questions I will be extremely greatful. thanks!

[Styrak]

- Half teeth pistons are used with higher-torque gearsets that are helical.
- Same-manufacturer parts are recommended to go with each other, but it doesn't have to be that way.
- Bearing piston heads are better for stronger springs, since the bearing allows them to rotate if they get torqued one way or the other and not jam up, etc. with a bearing spring guide a bearing piston head is not really necessary, but it won't hurt anything to have both.

[namloot]

A bearing spring guide is much less problematic then a bearing piston head. If you use a bearing spring guide, also using a bearing piston head is totally redundant.

[TriChrome]

Originally Posted by namloot

A bearing spring guide is much less problematic then a bearing piston head. If you use a bearing spring guide, also using a bearing piston head is totally redundant.

It is not redundant if you use PDI springs, which are arguably the best springs on the market (at least their 170 and 190%'s) since they're the only ones that are progressively wound. These springs like to twist as they compress much more than regular springs and bearings on both sides are beneficial.

It's also to note that most of the higher quality internal parts come with bearings on both the spring guide and piston head. I've never broken the bearings on any part I've ever used in over 4 years of hard tuning (but of course I always use quality parts).

[ILLusion]

Originally Posted by Styrak

- Half teeth pistons are used with high torque gearsets.

Statement corrected.

[ujiro]

Originally Posted by TriChrome

It is not redundant if you use PDI springs, which are arguably the best springs on the market (at least their 170 and 190%'s) since they're the only ones that are progressively wound. These springs like to twist as they compress much more than regular springs and bearings on both sides are beneficial.

It's also to note that most of the higher quality internal parts come with bearings on both the spring guide and piston head. I've never broken the bearings on any part I've ever used in over 4 years of hard tuning (but of course I always use quality parts).

Now if only they could get their packaging right. I destroyed my old stock TM gearbox (well, minor upgrades such as bushings, spring guide, etc) with a PDI spring that had been mislabeled and there was a PDI190 in there.

Or have they fixed that issue.