Ariel JGJ Series, Technical Manual

Page: 96 / 141

F
OR
M
ODELS
: JGW, JGR
AND
JGJ S
ECTION
5 - M
AINTENANCE
PAGE 5 - 24 1/01
Determining Ring Wear:
Ariel recommends replacing rings when the end gap has increased three times the new
dimension. To measure the end gaps, insert the rings in the cylinders without pistons. (See
Table 1-7 on page 1-11, Table 1-8 on page 1-12 or Table 1-9 on page 1-13 for new end gap
dimensions.)
Removal:
See paragraph 4 at “Piston and Rod - Removal” on page 5-18 for piston ring removal.
Wear Bands
All RJ/HJ Class pistons use one, one-piece angle cut filled Teflon wear band.
Determining Wear Band Wear:
Since the wear band does not work as a sealing ring, end gap is not critical. The amount of
wear band projection beyond the outer diameter of the piston is important. Wear band pro-
jection can be checked by measuring piston to cylinder bore clearance at the bottom of the
bore. This can be done without removing the piston from the cylinder. Replace the wear
band before it has worn enough to allow the piston to touch the cylinder bore.
Piston Rings - Installation
1. Place the rings over the grooves in the piston. Compress the Teflon one-piece
rings by hand.
2. With the rings fully compressed in the grooves, insert the rod and piston into the
cylinder. Make sure the one-piece rings stay in place while inserting the piston
and rod.
NOTE: RING GAPS ARE TO BE STAGGERED AROUND THE PISTON, RATHER THAN
IN LINE.
3. Follow the steps under “Piston and Rod - Installation” on page 5-21.
Wear Band - Installation
Install the wear band as if it was another piston ring as above.
Piston Rod Pressure Packing
-
Removal
1. Remove the piston and piston rod. See “Piston and Rod - Removal” on page 5-
18.