Piston & Cylinderblock differens?

[Johan.c]

Hello every one,
I have a question regarding a 2.5-16 M102.990 engine and the piston
compeard to the engineblock

From the piston in 0° (OT) to the block, how many mm + or - shold it be??


The engine on the picture have aprox. ≈ -0.85mm from the deck down to the piston
Is that right???????

the pics wear taken before cleaning of the piston

[meisterjäger]

[JM Motorsport]

[Johan.c]

[Tising]

[Johan.c]

[Tising]

I know. It is really secret. So don´t tell anyone, they might get killed.

[Tising]

[Racing]

Jamen Kim...du förstår ju själv..gossarna skall åka amerikanska delar i sina motorer...*suckar uppgivet å skakar på huvudet*...

[meisterjäger]

[Tising]

Så, Jesper

Nu skal du være sød

[Henger]

Ich glaube auch das in dem Motor von JM Motorsport die falschen Kolben verbaut sind.
Vielleicht vom 2.3er USA bzw. in der WIS findet sich noch eine Schweizer Version vom 2.3er die lediglich 9,2:1 verdichtet ist.

Wenn ihr die Kolben ausgebaut/identifiziert habt, Poste bitte das Ergebnis.

Gruß Fränk

[Johan.c]

No, the engine is a genuine 2,5-16 m102.990!
The compression was tested and it was 9.7:1.

So, this is how the pistons look like in a "late" 2.5-16.
Even my 2.5-16 that was produced 1992-11-10 has this kind of pistons.

And both cars has bin imported from Germany whit old W.German number plates!

[Johan.c]

Hear is a new pic when the piston is in OT

[Racing]

Frank et al.
Johan and me started doing the math.
IF the "brennraum" of the 2.5 clocks in at the same CCs as the 2.3...the numbers match.
In that case to reach an Eta of 9.7:1 the piston need to have its TDC 0,8mm down the bore.
That is IF the combustion chamber is the same volume as is the 2.3-which might very well be the case.

Epsilon=Vs+Vk/Vk.

Vs= (Pi*bore2 and divide by 4)*stroke

Bore and stroke in centimeters.

Vk=combustion chamber volume in cc:s

That formula can also be translated into
Vk= Vs/epsilon-1

Easy enough i guess...

[Henger]

Ich habe hier noch 2 Bilder von meinem Motor mit demontiertem Z-Kopf.


Leider sieht man das mit dem Kolbenunterstand nicht wirklich auf den Bildern.
Ich werde meinen Z-Kopf wahrscheinlich über Winter nochmals demontieren, dann schaue ich mir das mit dem Kolbenunterstand mal genauer an.

Gruß Fränk

[Racing]