DAIHATSU HINO HONDA ISUZU MAZDA
MITSUBISHI NISSAN SUBARU SUZUKI TOYOTA
DAEWOO BED FORD BMC CHEVROLET CHRYSLER
FIAT FORD HILLMAN HOLDEN JEEP
LADA LANDROVER MERCEDES BENZ PEUGEOT RENAULT
TRIUMPH VAUXHALL VOLKSWAGEN OTHER SNOWMOBIL
BRIGGS&STRATTON COMPRESSOR SNOWMOBILE KOHLER LAWNBOY
RACING CAR SHAPES OF PISTON HEADS

ALUMINUM ALLOY PISTON MATERIALS
Chemical composition%

NO. Cu Mg Ni Si Ti Fe Zn Mn
JIS AC8A LM13, A132 0.8-1.3 0.8-1.5 1.0-1.5 11.0-13.0 <0.2 <0.8 <0.5 <0.5
JIS AC8B LM26, F132 2.0-4.0 0.5-1.5 0.5-1.0 8.5-10.5 <0.2 <0.8 <0.5 <0.5
TS-20(TWL) 0.5-2.5 0.5-1.5 0.5-1.5 19.0-22.0 <0.5 <0.8 <0.5 <0.5
JIS AS-23 LM29 0.5-2.5 0.5-2.5 0.5-1.5 22.0-24.0 <0.5 <0.8 <0.5 <0.5
JIS AC9A 0.5-2.5 0.5-1.5 0.5-1.5 22.0-24.0 <0.2 <0.8 <0.2 <0.5
JIS AC9B 0.5-2.5 0.5-1.5 0.5-1.5 22.0-24.0 <0.2 <0.8 <0.2 <0.5
AC9C 0-2.5 0.5-1.5 0.5-1.5 18.0-20.0 <0.2 <0.8 <0.2 <0.5

Mechanical Properties
NO. (Heat-treatment) (Tensilestrength)
(kg/mm2)
(Hardness) (Elongation)
%
(Thermal Expansion) (Specificgravity)
g/cm3
20o-100oC 20o-200oC 20o-300oC
AC8A T6
T7
>28
>25
64-74
55-65
>0.5
>0.6
19.2 x 10-6 20.6 x 10-6 21.9 x 10-6 2.73
AC8B T5
T6
T7
>23
>28
>25
57-69
64-74
54-66
>0.5
>0.5
>0.6
20.2 x 10-6 21.6 x 10-6 23.1 x 10-6 2.75
TS-20 T5
T6
T7
>20
>22
>21
57-69
64-74
55-65
>0.3
>0.3
>0.3
7.2 x 10-6 18.6 x 10-6 20.1 x 10-6 2.70
AS23 T6
T7
>18
>18
63-75
54-66
>0.3
>0.3
16.5 x 10-6 16.5 x 10-6 18.0 x 10-6 2.68

Heat Treatment
Type Annealing Hour Quenching Re-annealing Hour
T5       170o-200oC 10HR
T6 475o-510oC 8HR 475o-510oC 175o-205oC 10-12HR
T7 470o-510oC 8HR 470o-510oC 210o-240oC 10-16HR

Chemical composition limits of piston pin %
No. C Si Mn P S Mo Cr
SCM-415H 0.13-0.18 0.15-0.35 0.60-0.85 <0.030 <0.030 0.15-0.35 0.90-1.20

Chemical composition limits of Ni-Resist (Ai-fin) %
Hardness: HB 130-200          HRB: 73-93
No. T.C Si Mn Ni Cu Cr Fe
Ni-Resist <3.0 1.0-2.8 0.5-1.5 13.5-17.5 5.5-7.5 1.5-2.5 Ba1

Chemical composition limits of CYL. LINER %
No. C Si S P Mn Ni Cr Cu
Centrifugal Cast Zrayiron 3.25-3.65 2.20-2.60 <0.10 <0.20 0.45-0.65 0.05-0.20 0.20-0.40 0.45-0.75


ILLUSTRATION OF SOME IMPORTANT PISTON DESIGNS
1.Auto-Thermic pistons have cast-in steel struts
   between the skirt and pin bosses. When the piston
   heats up, these struts have the effect of limiting the
   expansion of the piston in the direction of the thrust
   axis. Transverse slots at the same time prevent
   passing of heat. Potential weakness and less
   combustion press endurance is the obvious defect
   for this type of pistons.
2.This kind of piston also has cast-in steel struts, but
   without transverse slots in the ring groove. It
   combines extremely smooth running with a high
   degree of strength for high-output engines.
3.The top and sometimes lower compression ring
   grooves are machined into Ni Resist Bonded insert.
   This insert counteracts the high degree of wear
   occurring in the top groove, This type is applied to
   Diesel engines, particularly those with turbocharging.
4.Special head shape (combustion chamber)
   especially for diesel engines.
5.Pistons with cooling channel are used whenever
   high operating temperature occurs. This intensive
   oil cooling counteracts the high temperatures in the
   piston crown and ring belt.

A DESCRIPTION OF FOUR TYPICAL PISTON TYPES
1.PLAIN, SOLID SKIRT, OPEN-ENDED
This type is very strong but heavier and has its skirt connected to its head region all the way round. 
It is necessary to allow more clearance, especially at the top of skirt to avoid seizure.

            

2.TRANSVERSE SLOT, OPEN-ENDED
Such a piston is thermally compensating and can usually be operated at smaller clearances at the top 
of the skirt in the interests of noise reduction.

            

3.SOLID SKIRT SLIPPER
This type of piston has no thermal slot but the skirt is heavily cut away in the pin axis to reduce 
weight and avoid swaying. It is also more rigid and usually needs greater clearance than other types, 
but is the strongest one.

            

4.TRANSVERSE SLOT SLIPPER
Contrary to solid skirt slipper type, this type has a cast or milled transverse slot in the oil ring 
groove for thermal compensation.
Smaller clearance at the top of the skirt is requried , in the interest of quiet operation.

            

 

IMPORTANT PISTON TERMS

A.
B.
C.
D.
E.
F.
G.
H.
I.
J.
K.
L.
M.
N.
+.
-.
Cylinder Bore Dia. (Std. Size)
 Piston Pin Dia.
 Compression Height
 Ring Land
 Ring Groove Dia. (Comp. Ring)
 Bottom Ring Groove Dia.
 Piston Pin Length
 Upper Oil Ring Groove Dia.
 Circlip Width
 Upper Oil Ring Width
 Oil Hole Dia.
 Piston Length
 Distance between the Bossen
 Comp. Ring Width
 Height of Dome
 Depth of Dish

Copyright (C) YONG CHIANG PISTONS CO., LTD. Taiwan Products, China Sources, China Trade.