Timing chain cover bumper

[Bob Snow]

I am suppose to have a 1989 Jeep Wrangler with a 4.2 AMC Engine. I am doing a overhaul of the engine. Took off the timing cover to replace timing gears and chain. Chain was very loose and there appears to be the remnants of a chain bumper on the inside of the cover. Chain had chewed it up. In doing some research and trying to detrmine if I need to reuse or replace I found that apparently prior to 1991 there was no chain bumper. I have not been able to find one to order that has the bumper. Does anyone know if a bumper is absolutely necessary. Also how can I tell what year engine I actually have?

 

[superj]

the block has the year as part of a code on the driver's side back by the firewall. its just visible if you look under the intake from standing on the side of hte engine bay with a flashlight