crankshaft seal, rear main, rubber, Best Gaskets
Automotive Engine Rebuilders Association, AERA TB2025
The AERA Technical Committee offers the following information on the rear main bearing seal caution on 1939-71 Jeep 2.2L engines. These engines are sometimes referred to as the F & L head engines.
During production of these engines, two different cylinder blocks were manufactured. The early cylinder blocks had a rope rear main seal installed in them while later production blocks had conventional type rear main bearing seal installed in them.
When assembly of these engines is taking place, make sure you have the correct type of seal will help prevent engine failure. If the conventional rear main seal is installed in the early blocks that require a rope seal, there may be a possibility if bearing failure. On the conventional seal is an arrow showing the direction of the crankshaft rotation as shown in Figure 1. This arrow (marked with white) should be visible form the rear of the engine when properly installed.
One way to verify that you are using the correct rear main seal is that the conventional seal is used on crankshafts that have a rear crankshaft seal area diameter of 2.3202 - 2.312. The rear main bearing seal has to be lubricated during installation. If the seal is to tight, no amount of special type lubricant will make it work properly. Rear main bearing seal fit has to be correct or a leaking rear main bearing seal and/or a possible rear main bearing problem can occur.
The AERA Technical Committee