I don't follow you, you took the timing chain cover off to change the rear main seal????
Can't help on setting the chain, ain't done it. Oil pressure , standerd rule of thumb is 10 psi for every thousand rpm. I don't like to see it under 20 psi at idle though myself and should never go over 80 psi or you got big problems.

Can't help on setting the chain, ain't done it. Oil pressure , standerd rule of thumb is 10 psi for every thousand rpm. I don't like to see it under 20 psi at idle though myself and should never go over 80 psi or you got big problems.