Bulletin No. 1.62-14 Group No. 1.62 March 6, 2008 Page 1 of 2

4.5T and 6.8T Powertech Cylinder Kit

Reliance Parts Corporation is pleased to announce the availability of the latest style cylinder kits for the 4.5T and 6.8T standard horsepower engines. These new cylinder kits carry part number NRE-50790 and replace NRE-505111. Shown below is the bill of material for this new cylinder kit:

NRE-507920 Cylinder Kit:

NRE-515372K Piston w/Pin and Retainers

NR-121867 Cylinder Liner

NRE-507852 Ring Set

NAR-65507 Kit, Liner O-Ring

Notice that the piston and ring set have changed in this cylinder kit. The piston NRE-515372K. The ring set is NRE-507852 uses a torsional keystone ring set as opposed to the conventional keystone ring used in ring set NRE-66271. Piston part number NRE-515372K is the latest design and manufactured specifically for use with torsional keystone top ring.

These cylinder kits should not be intermixed within an engine with NRE-505111 cylinder kits.

We will continue to offer ring set NRE-66271 used in cylinder kit NRE-505111 but will no longer offer piston part number NRE-505100 used in that cylinder kit.

Overhaul kit part numbers RP812, RP813, RP818, RP819, will remain the same. Care should be taken if cylinder kits are sold separately from overhaul kits, that the two cylinder kits are not intermixed in an engine.

Attached is a drawing showing the differences between current and former ring sets used in 350 Series Powertech engines. Please use care to be sure that ring sets are used in the proper combination with current pistons.

More and more 350 Series Powertech engines enter the overhaul cycle every day. Be sure to include these popular and latest design cylinder kits and overhaul kits in your next stocking order.

Bulletin No. 1.62-14 Group No. 1.62 March 6, 2008 Page 2 of 2

4.5 and 6.8 Powertech Ring Sets
	Former Ring Set	Former Ring Set	Current Ring Set
	NRE66271	NRE66820	NRE507852
Top Ring Profile	Full Keystone	Full Keystone	Torsional Keystone
Dimensions (Height x Width)	2.35 x 3.75mm 0.092 x 0.147”	3.00 x 4.35mm 0.118 x 0.171”	3.00 x 4.35mm 0.118 x 0.171”
Middle Ring Profile	Reverse Torsional	Reverse Torsional	Reverse Torsional
Dimensions (Height x Width)	2.35 x 4.70mm 0.092 x 0.185”	2.35 x 4.70mm 0.092 x 0.185”	2.35 x 4.70mm 0.092 x 0.185”
Bottom Ring Profile	Coil Spring Loaded Beveled Oil Control Ring	Coil Spring Loaded Beveled Oil Control Ring	Coil Spring Loaded Beveled Oil Control Ring
Dimensions (Height x Width)	3.45 x 2.80mm 0.135 x 0.110”	3.45 x 3.15mm 0.135 x 0.124	3.45 x 2.80mm 0.135 x 0.110”
Used on Pistons Marked	NRE505100, NRE505101	NRE505102	NRE509540, NRE515372
Used in Cylinder Kits	NRE505110, NRE505111	NRE505112	NRE507850, NRE507920

Please note that each set differs only slightly. Caution should be exercised, as none of these are interchangeable and must be used in combination with the pistons and cylinder kits as shown only.