Cylinder Block - Identification

Group 11
Engine

Bulletin Number
11 02 97

Woodcliff Lake, NJ
June 1999
Product Engineering

This Service Information bulletin supersedes S.I. 11 02 97 dated March 1997 which should be removed and discarded from your S.I. binder.

Changes to this revision are identified by asterisks.

SUBJECT:
Cylinder Block Identification

MODEL:
All with M60 and M62 engine

Situation:
The cylinder wall appearance differs between Nikasil (aluminum alloy block with nickel dispersion-coated cylinder bores used on the M60 engines and M60 replacement blocks) and Alusil engine blocks (aluminum silicon alloy used in M60 replacement, M62, M70 and M73 engines).

The Nikasil version incorporates crosshatch hone marks in the cylinder bore finish.

Nikasil Version:

The Alusil version has a smooth gray cylinder bore finish without the crosshatch hone marks.

Alusil Version:

Note:
**The cylinder bores of an Alusil engine block which has been operated (used engine) may show signs of cylinder wall wear as seen in the illustration below. The bores may have shiny spots and light vertical surface scratches which is a normal wear pattern for a used engine as compared to new (never used) Alusil cylinder bores with the mat gray finish.**




**Engine bores should never be condemned by the surface appearance and must always be measured using a bore gauge as outlined in the repair manual group 11 section 11 25 for proper cylinder bore/piston wear analysis.**

**The maximum cylinder bore taper and out-of-round specifications for all M60 and M62 engines are:
0.007 mm (0.00027 in.) New Engine (Never run)
0.04 mm (0.0016 in.) Used Engine (Combustion has taken place in the cylinder)**

Due to the different characteristics of the Nikasil and Alusil engine blocks, different pistons and piston rings are installed and should never be interchanged.

If an engine repair becomes necessary on an M60 engine where piston and/or piston rings must be replaced, the cylinder block must be identified first because some M60 replacement blocks have an Alusil finish.

The seven digit casting number located on the right side of the engine block next to the coolant drain bolt must be used to determine if a Nikasil or an Alusil block is installed.





The cylinder block casting number applications are:
Casting Number Cylinder Block Version
1 725 970 or 1 741 212 M60 B30 Nikasil
1 745 871 M60 B30 Alusil
1 725 963 or 1 742 998 M60 B40 Nikasil
1 745 872 M60 B40 Alusil
1 745 873 M62 B44 Alusil

Warranty Information:
Information only.