Running engine with valve cover removed?

Diy’er curiosity. My Chilton’s repair manual for early 70’s Ford trucks suggests it is possible to run the V8 302 engine for a short time, at idle, with a valve cover removed; e.g. to diagnose valve noises. I’d guess trying that idea would spray oil all over the engine compartment and make big mess. Or is that actually a viable idea w/302, not much oil gets sprayed out?

It IS viable, it DOES make a bit of a mess. Expect to clean things off afterwards. There are little clips than can be placed over the pushrod holes in the rocker arms to deflect most of the squirt.

I have adjusted valve clearances with hydraulic lifters that way. It is messy.


You put rocker stoppers on the rocker arms to cover the oil holes so that doesn’t happen.




I was wondering if mechanics use some sort of engine-compartment cover esp for that purpose? Like a heavy-duty canvas tarp with rectangular hole the exact size of the valve cover.

Or aluminum foil and duct tape to redirect the oil. Or alaminium foil if you aren’t from here. But I’ve never tried it. It was pretty obvious where the problem was without starting the engine.

On push rod engines plugging the holes in the rockers seemed to prevent any problems with oil loss beyond what is dripped off mt hands and tools. And if the noise is there when the valve cover is removed with the engine idling the noisy rocker can be quickly identified .

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