Hello every body! Long time reader first posting. Well I just got ahold of this 1985 cj7 with an 4.2 in-line 6. I sent the engine out for rebuilding got it back now it’s time to get busy. I started putting the timing belt cover back on and noticed something missing. Seen some videos and looks like I’m missing the plastic tensioner that goes inside. My question is do I really need this piece? Also I read to use perfect seal for the gaskets can I use something else, can’t find that stuff except online. Thank you!