Canada - Engine - Reuse Guidelines And Torque Specifications

GROUP
ENGINE MECHANICAL

NO.
02-20-008

DATE
SEPTEMBER 27/02

MODEL
ALL

SUBJECT

CYLINDER HEAD, CONNECTING ROD, AND MAIN
BEARING BOLT REUSE GUIDELINES AND
TORQUE SPECIFICATIONS











This bulletin goes beyond the shop manuals and provides reuse guidelines and tightening torque procedures for cylinder head, connecting rod, and main bearing bolts that are tightened using the torque-angle method. Also included are Shop Manual corrections for torque specifications.

Fasteners tightened by the conventional torque only method can have substantial clamping force variations. The variations come from several factors such as fastener friction and hand tightening versus power driver tightening methods.

Fasteners tightened by a low initial torque value then tightened by an additional torque-angle value are known as torque-angle bolts (or sometimes torque-to-yield bolts). These types of fasteners can achieve very high clamp loads with very small variations.

INSTALLATION NOTES:

1. Torque angle gauges are available from Kent-Moore (P/N BT-8653-A) and are a part of the essential tool package.





2. Some of the fasteners described require a measurement as a check prior to reuse. Always measure the shank of the bolt, not including the head.





3. Always use engine oil to coat the threads and both sides of the washers of a torque angle fastener. (See below)

4. Always use a torque wrench to achieve the initial torque value.

5. If there is a question to the condition of the fastener (ex. corrosion), replace the fastener.