Pistons for m20 Stroker

[.n0iz4!]

Hey Guys,

i'm from Germany and new here and sorry for my (bad?) englisch.
I dont want to open a new Thread, so i have a Problem.

Ive bought the Wiseco Pistons with 8.8:1 CR Pistons and wanna build a M20B28. I wanna increase the CR with changing the Dome Volume, but thats not the point.

I made a 3D-Modell with Solidworks but the" Valve Pocket Depth" is my Problem.
The Kit Specifications says: "DEPTH FROM TE: Intake: -0,1050 (-2,667mm)"

Does TE stands for Top End? But where the f**k is this?

Can someone help me out?

[zaq123]

Hey Guys,

i'm from Germany and new here and sorry for my (bad?) englisch.
I dont want to open a new Thread, so i have a Problem.

Ive bought the Wiseco Pistons with 8.8:1 CR Pistons and wanna build a M20B28. I wanna increase the CR with changing the Dome Volume, but thats not the point.

I made a 3D-Modell with Solidworks but the" Valve Pocket Depth" is my Problem.
The Kit Specifications says: "DEPTH FROM TE: Intake: -0,1050 (-2,667mm)"

Does TE stands for Top End? But where the f**k is this?

Can someone help me out?

wiseco typically gives you their piston's dome and valve pocket spec. My understanding is TE is the top end of the piston and the intake pocket is down "-" 2.667 mm from piston's top end at the specified angle

[.n0iz4!]

wiseco typically gives you their piston's dome and valve pocket spec. My understanding is TE is the top end of the piston and the intake pocket is down "-" 2.667 mm from piston's top end at the specified angle

The Angle is 22°. But the depth from there is around 5mm.

I dont know from where they measure


EDIT:

Mahle Original Depth (8.8)


Mahle Original Depth (9.7)


Best lookin is this: Intake 42mm in 22° Angle

[zaq123]

you are measuring ~5mm from the dome height. Wiseco gives you the depth from the deck height (piston deck)

[.n0iz4!]

you are measuring ~5mm from the dome height. Wiseco gives you the depth from the deck height (piston deck)

Ok, from Pistondeck, to vertical deepest point, right?




Looks like this...
better, but does not seem to be completely correct. (Depth 43,7mm to Piston Pin Center)

[zaq123]

this is how I understand it. Courtesy of AutoCad 2019 edition.

[.n0iz4!]

this is how I understand it. Courtesy of AutoCad 2019 edition.
]

:D

That would change the length from piston pin center to pocket end 43,935mm
(Ok its deeper than the original 44,3 - but the look doesnt fit to the original. And yes, the other things are correct.)

Edit: One moment. ill correct.

(Piston pin center to valve pocket bottom)
Original Mahle Piston 8,8:1 = 44,3mm
Original Mahle Piston 9,7:1 = 43,7mm

With your idea it would be 43,935mm and looks like this:

[zaq123]

:D

That would change the length from piston pin center to pocket end 43,935mm
(Ok its deeper than the original 44,3 - but the look doesnt fit to the original. And yes, the other things are correct.)

what? sorry

[zaq123]

I'm getting inspired with my art skills now. Definitely need to explore it further

[.n0iz4!]

This is how it should looks

[zaq123]

I can see the difference it your plotting and your actual pistons. However you keep referring to Mahle piston specs (pin center to valve etc). Do you have all specs for Wiseco dimensions?

Typically, valve relief depth is measured vertically from the deck to the deepest part of the valve relief radius. That makes my picture above not exactly precise (red line needs to be vertical). I didn't know you are trying to reproduce it precisely when did that pic. Just tried to convey the idea explanation about TE measurement and where it starts from.


P.S. What are you trying to figure to? If Wiseco pistons match your desired spec?

[.n0iz4!]

I can see the difference it your plotting and your actual pistons. However you keep referring to Mahle piston specs (pin center to valve etc). Do you have all specs for Wiseco dimensions?

Typically, valve relief depth is measured vertically from the deck to the deepest part of the valve relief radius. That makes my picture above not exactly precise (red line needs to be vertical). I didn't know you are trying to reproduce it precisely when did that pic. Just tried to convey the idea explanation about TE measurement and where it starts from.


P.S. What are you trying to figure to? If Wiseco pistons match your desired spec?

No i just have the Mahle Specs. (And of course the specs from the kit. But theres no other info about the valve pockets etc..)

The Vertical option seems good to me, but that even looks not right..
Unfortunately..

I wanna offset the whole "surface" and lower it. Maybe -1mm.
But not the Dome depth. This increases the CR of the Pistons.
1mm should end up around 10,5:1.

[digger]

example of how they are spec'd often

[.n0iz4!]

example of how they are spec'd often

This looks good to me

hmm..I think could be it. (please correct, if its wrong :D) the length is also ok. (43,318 - deeper than original)
(the Radius makes the difference!)

Thanks for your fast help guys!

[digger]

the is a stock 9.7:1 piston i modeled a while back