Perkins 4.99 - Piston Ring Fitting

A----+--O
F6
Fitting the Piston Rings
Fit piston rings to the piston. Rings vary according to
engine type and application as follows: reading from
the
top of the piston.
4.108 Engines
Standard Pistons
: 1.
12.
I
1
3
.
14.
15.
I ,
I
Plain parallel faced compression
Internally stepped compression
Internally stepped compression
Laminated segment oil control'
Slotted scraper
Engines rated at 3,000 rev/min and below have a
slotted scraper fitted in the fourth groove which
has the same width, clearance and gap as the
fifth piston ring.
; Controlled Expansion Pistons
: These have either four or three rings per piston as
I
follows:
PISTONS AND CONNECTING RODS-F.3
: 1. Chrome insert parallel faced
I 2.
Internally stepped
I 3. Internally stepped F8
: 4. Spring loaded scraper
I 1. Chrome taper faced
I 2.
Internally stepped taper faced
: 3.
Spring loaded scraper
F7
4.99 Vehicle Engines
1. Chrome parallel faced compression.
2. Internally stepped compression.
3. Internally stepped compression.
4. Slotted scraper.
5. Slotted scraper.
4.107 and 4.99 Agricultural and Industrial
Engines
1. Plain parallel faced compression.
2. Internally stepped compression. *
3. Internally stepped compression. *
4. Chrome spring loaded scraper.
5. Slotted scraper.
*4.99 agricultural engines have taper faced cast iron
compression rings fitted in the 2nd and 3rd ring
grooves.
After an appropriate period of service, when indica-
tions of piston ring and/or cylinder bore wear may be-
come apparent, a replacement ring pack has been
made available for fitting exclusively to 4.99 service
engines and includes a taper faced ring for fitting in
the
top ring groove.
NOTE: All the rings quoted above except the laminated
and spring loaded type may be fitted by means of an