I have a Chilton repair manual for 1964-73 Mustang/Cougar. For valve adjustment it says to bring the engine to operating temp, remove the valve covers, and start the engine to do the adjustment. I have never adjusted valves with an engine running. Why is it done this way? If this is true, does anyone have any tips on how to do this without getting oil everywhere?
Ok, I got some old valve covers coming. I’m going to cut the tops off & use them for the valve adjustment. Answered my own question.
Only cut a small section out of the old valve cover right above the adjusting nuts otherwise you will get oil everywhere.
I just did an adjustment on my 67 289 2v this weekend, it had been rebuilt 5k miles ago and a couple lifters were starting to tick when warmed up. The way I often do it is just get the engine to temp, pull the covers and tighten each one until I can barely turn the hot oily push rods with my fingers. You will have to turn the engine over a couple times to get all positions off a cam lobe. The best way is to sacrifice a valve cover and make little tabs that slide out of the way so as to keep oil from squirting.