The Stovebolt Site Forums The Shop Area Engine Shop pushrods and rockers

I just did another valve adjustment on my 56 235. The last time I did it a month ago I got a clicking that I just can't seem to pin down. After today's adjustment (to try to get rid of the clicking) I still have the clicking. Worse at startup cold, then gets a little quieter running when warmed up, but I can still hear it. I noticed some play when I was adjusting, play that lets me move several of the rocker arms up and down a little at the pushrod end. That naturally changes the gap. 6 exhaust is the worst, most are ok. Any thoughts on what that means? Can it be the pushrods and/or the rockers are worn and won't really adjust correctly? Could that cause the clicking? Or am I doing something incorrect when I'm adjusting. I followed the adjustment tips in Tech Tips. Dale

Are these solids or hydraulic lifters?

They are solid as far as I know - the engine is original and has never been rebuilt.

Have you looked at the face of the rockers where they contact the valves?
The rockers get a recess worn in them where they contact the valve. If not refaced before adjustment the feeler gauge bridges the worn area giving you a false and loose adjustment.

I have not looked at them, but that is a good possibility. Is it necessary to remove the rocker arm to see if the face is not flat? And reface if needed?

I choose a rocker next to a long spring to check first.
Make sure the rocker you are checking is not holding a valve open.
Back off that adjuster and that lets you slide the rocker against the spring to a point that it clears the push rod and you can turn it on the shaft to a position where you can see the contact area.

I will try that -- it seems a good place to start -- Thanks Dave

Dale

I too had a upper end tap that I just couldn't get rid of, turned out I had some very badly worn guides and the valve stem would move outboard during lift. About 1/16" of the valve stem was visible past the rocker arm on the number 4 and 5 intake valves.

if you do have worn rockers with only a groove worn into them, (which would be very likely on an engine that old) you can get a decent adjustment with a feeler gage cut down to slightly narrower than the valve stem. Except for the 4 years or so I had the engine with the rebuilt rockers, I have done it for 30 years now. However they can wear far enough where there is an actual recess in the rocker. At that point they need to be refurbished. Several places do it, I had Larrowe and sons do mine, I was very pleased. But then again being that old you (well, I don't know about YOU personally, I meant your trucks engine) most likely have worn guides as well as any other malady that may strike this area of the engine.

How I found my worn guides was first with a auto stethascope locating the area of the noise. This put me right on the number four and 5 intake valves then by removing the spark plugs and rotating the engine by hand and watching the movement of the top of the valve as it went through it's lift cycle. When I removed the head off the truck and disassembled the spring off those valves it was very clear what the issue was. As soon as the valve came off the seat, the top of the valve could be wiggled 3/16" of an inch. Oddly enough the seats were still fine. The engine idled with 21" vacuum and had good compression too.

Thanks for the info on your experiences. I will take it down again so I can see the condition of the rockers and the guides. If they are so worn (and I suspect they are) I may seek some professional help in refurbishing if it seems feasible so to do. At some point I know this old engine with it's many moving and rubbing against each other pieces will just need a refreshing rebuild. In the meantime it still gets me from here to there. BTW Brokenhead, this old truck is a youngster compared to me so your observations were spot on. But I'm still running too and getting from here to there just fine. Just have to push up on the "rocker arms" now and again. Thanks for your help - Larrowe sounds like a good mechanic shop.

Sstock? - did you hold the stethescope on the valve cover before you took it off to listen. Have not tried that but seems a good way to find a click. Thanks, Dale