FI Forged pistons from other cars for various bores: M42/M44/overbore

[nuvolarossa]

Hi, I'm searching to make a list for what pistons can be used from other cars, for use with turbo or supercharger on our M4x, instead of buying expensive custom pistons.
 
the list will be something like this.

Code: [Select]


 
1) OEM M42 block, 84mm
 
a) from car xxx model yyy
PISTONS: bore xx
compression height:
pin diameter:
RODS:
 
2) OEM M44 block, 85mm
 
a) from car xxx model yyy
PISTONS: bore xx
compression height:
pin diameter:
RODS:
 
3) block overbored to 86mm
 
a) from car xxx model yyy
PISTONS: bore xx
compression height:
pin diameter:
RODS:
 
So clear from you mind the template of the list upper. I'll upgrade it when more info will come.
 
Let's start with options for 86mm bored blocks:
 
OPTION #1 FOR 86mm BORED BLOCK: AFTERMARKET FORGED PISTONS FOR OPEL C20LET ENGINE
Ludiagsm use 86mm Wossner forged pistons for C20LET, with a 86mm bore block. They have 30,43mm of compression height, and they use a 21x13x55.5mm pin . So this is his setup:
 
PISTONS: 86mm bore from C20LET
compression height: 30,43mm
pin: 21x13x55,5mm
RODS: 138,8mm from honda K20A, 51,1mm big diameter
 
But he grinds the engine block 2mm, then he has 1mm clearence between up site of pistons to the top level of engine block. He says that the engine with this setup has a cr of 7,9:1.
 
So, for not grinding the block, we need
-a piston with 2mm more compression height for fit with that honda short rod.
- or a rod 2mm more lenght with same other specs as honda one.
It's right this theory?
 
OPTION #2 FOR 86mm BORED BLOCK: OEM FORGED PISTONS FOR OPEL C20XE ENGINE
 
PISTONS: 86mm bore from C20XE
compression height: 30,43mm
pin: oem opel 21mm
 
OPTION #3 FOR 86mm BORED BLOCK: AFTERMARKET FORGED PISTONS FOR TOYOTA MR2 TURBO 3s-gte ENGINE
PISTONS: 86mm bore from 3S-GTE
compression height: 35mm
pin: 22mmX14mmx63mm
RODS: NISSAN SR20DET, 136.25mm, 22mm pin diameter
still lot to check about option #3...
 
this is what I've found this night... here now is night:D
 
if you find some compatible parts that are oem forged it's better because they can be found used, and they will cost nothing compared to aftermarket brand parts.
 
 
I need "Cylinder head combustion chamber volume" and "DECK HEIGHT" from a oem M42 and from M44, please, so I can calculate the static compression ratio with new parts.

[95isTurbo]

Hi, I'm searching to make a list for what pistons can be used from other cars, for use with turbo or supercharger on our M4x, instead of buying expensive custom pistons.
 
the list will be something like this.

Code: [Select]


 
1) OEM M42 block, 84mm
 
a) from car xxx model yyy
PISTONS: bore xx
compression height:
pin diameter:
RODS:
 
2) OEM M44 block, 85mm
 
a) from car xxx model yyy
PISTONS: bore xx
compression height:
pin diameter:
RODS:
 
3) block overbored to 86mm
 
a) from car xxx model yyy
PISTONS: bore xx
compression height:
pin diameter:
RODS:
 
So clear from you mind the template of the list upper. I'll upgrade it when more info will come.
 
Let's start with options for 86mm bored blocks:
 
OPTION #1 FOR 86mm BORED BLOCK: AFTERMARKET FORGED PISTONS FOR OPEL C20LET ENGINE
Ludiagsm use 86mm Wossner forged pistons for C20LET, with a 86mm bore block. They have 30,43mm of compression height, and they use a 21x13x55.5mm pin . So this is his setup:
 
PISTONS: 86mm bore from C20LET
compression height: 30,43mm
pin: 21x13x55,5mm
RODS: 138,8mm from honda K20A, 51,1mm big diameter
 
But he grinds the engine block 2mm, then he has 1mm clearence between up site of pistons to the top level of engine block. He says that the engine with this setup has a cr of 7,9:1.
 
So, for not grinding the block, we need
-a piston with 2mm more compression height for fit with that honda short rod.
- or a rod 2mm more lenght with same other specs as honda one.
It's right this theory?
 
OPTION #2 FOR 86mm BORED BLOCK: OEM FORGED PISTONS FOR OPEL C20XE ENGINE
 
PISTONS: 86mm bore from C20XE
compression height: 30,43mm
pin: oem opel 21mm
 
OPTION #3 FOR 86mm BORED BLOCK: AFTERMARKET FORGED PISTONS FOR TOYOTA MR2 TURBO 3s-gte ENGINE
PISTONS: 86mm bore from 3S-GTE
compression height: 35mm
pin: 22mmX14mmx63mm
RODS: NISSAN SR20DET, 136.25mm, 22mm pin diameter
still lot to check about option #3...
 
this is what I've found this night... here now is night:D
 
if you find some compatible parts that are oem forged it's better because they can be found used, and they will cost nothing compared to aftermarket brand parts.
 
 
I need "Cylinder head combustion chamber volume" and "DECK HEIGHT" from a oem M42 and from M44, please, so I can calculate the static compression ratio with new parts.

that sounds like  a great alternitive to the money problem , all thore pistons and rods are very easy to get and they are cheap
+1

[Frankie]

Download from Mahle's homepage a program which has the product catalog and a convinient search engine in it.

Btw, what are the exact specs for the pistons you are looking for.

What is the wanted comprsssion height etc? I found that Nissan Primera has 86mm, 22m pin pistons (compression height 32mm)

[nuvolarossa]

Download from Mahle's homepage a program which has the product catalog and a convinient search engine in it.
 
Btw, what are the exact specs for the pistons you are looking for.
 
What is the wanted comprsssion height etc?

this is dependent from what rod can be used with it.
 
I want to find three rod-piston combos
1)that fitted on m42 (stock bored) give a compression ratio near 8:1
2)that fitted on m42 (bored to 86mm) give a compression ratio near 8:1
3)that fitted on m44 (85mm bore) give a CR of 8:1.
 
______________________________________________________________________________________________________________
EDIT: the E30 and e36 m42 pistons are differents! same bore, same compression height, but different combustion chamber volume...
 
all sizes are in mm.
KH=compression height
VT=valve recess depth
MT=combustion chamber depth
Mdiam=combustion chamber diameter
GL= total lenght
here are 318is E30 piston specs:

here are 318is E36 last M42 piston specs:

 
I need to know the head combustion chamber volume on m42 and m44, please
I know that 20% of combustion chamber volume is on the piston, the other 80% in in the head, but other than that I know nothing.

[ludiagsm]

on my m42 combustion chamber is 33ml .

don't forgrt the gasket on stock giotze gasket is 1,36-1,4mm

[nuvolarossa]

on my m42 combustion chamber is 33ml .
 
don't forgrt the gasket on stock giotze gasket is 1,36-1,4mm

thank you!

[nuvolarossa]

on my m42 combustion chamber is 33ml .
 
don't forgrt the gasket on stock giotze gasket is 1,36-1,4mm

33cc is the combustion chamber of m42 stock or it's from your modified engine(bored, with new pistons)?

[ludiagsm]

33cc is the combustion chamber of m42 stock or it's from your modified engine(bored, with new pistons)?

33ml that is combustion chamber only in head of stock E36 m42 engine