Usage:
Introduction
An integral counterweight crankshaft (the counterweights are cast as part of the crankshaft) is used in the above listed engines. This type of crankshaft can only be used in a cylinder block that has special machining that provides clearance for these counterweights.
If it becomes necessary to replace one of these cylinder blocks, because of damage, and the crankshaft is in good condition and still serviceable, it will be necessary to try to obtain an original 7C4839 Cylinder Block Group.
The 7C4839 Cylinder Block Group was the original cylinder block group used with the integral counterweight crankshaft. This cylinder block is now cancelled, but, a limited number are on hand in the parts department and will be available until all stock is exhausted.
NOTE: If a 7C4839 Cylinder Block Group is not available, there are two alternatives that can be considered to make the repair.
- * The first alternative is to use an appropriate service cylinder block group from another 3508 engine model. A 7W0210 Crankshaft Assembly can be installed as a service replacement for the original integral counterweight crankshaft.
NOTE: The integral counterweight crankshaft can not be used in a standard 3508 engine cylinder block unless there is some additional machining done within the cylinder block. This is because additional clearance is needed for the integral counterweights.
If it has been decided to use the original, undamaged, integral counterweight crankshaft, use the second alternative.
- * The second alternative is to obtain a standard service cylinder block. One that is normally used for a similar model 3508 engine.
- * Refer to the procedure given in the following topic entitled Modification of a Standard 3508 Engine Service Cylinder Block Group for use with an Integral Counterweight Crankshaft.
Use of this procedure to modify the standard 3508 service cylinder block, will provide the additional clearance needed for the integral counterweights.
Modification of a Standard 3508 Engine Service Cylinder Block Group for use with an Integral Counterweight Crankshaft
A. Front face of cylinder block.
NOTE: The view above is as seen from the bottom of the cylinder block.
1. Use the dimensions given at location (B) to do the machining of the cylinder block. Remove the necessary material as shown in the shaded areas at locations (B), (C), (D) and (E).
This view is seen as if looking through the cylinder block from front to rear. For orientation purposes, location (E) is actually at the left rear of the cylinder block.
When doing the machining at location (E), make sure that dimension (F) does not go deeper than the 25 mm (0.98") shown. If this dimension is maintained, it will reduce the possibility of cutting into the lubrication oil manifold for the piston cooling jet.
2. Be sure the machined surface has a smooth finish. Remove all burrs and thoroughly clean the cylinder block before assembly of the engine.
3. Refer to the Service Manual for any assembly procedures and/or specific torque values that may be needed.