Stop children what's that sound...


If any of you remember back in the late 60's the Buffalo Springfield song Stop Children what's that sound.

Well I have a sound in my old 860 tractor. I have to ask, "what's that sound". Some history. I got this tractor in a non-running condition 25+ years go. It had a broken cam shaft. The stub on the end where the timing gear attaches was broken off. There was no bolt and washer holding the gear on the cam. I bought and installed an new cam and and aluminum gear from the local Ford dealer. At the time, as I recall, they offered over size gears. I was puzzled by that as I was not sure how I would know how much over size to get, so I just got a standard one. Again, as I recall, the over sizes were in the range of 0.005, 0.010, etc. There was a little backlash when I reassembled the engine, but I did not think it was much.

The tractor runs great. Starts quick, runs smooth, strong, etc. Jump forward about 20 years, after getting warmed up, there is a clicking sound in the engine. Sitting at idle 400-500 rpm, the sound is very evident. RPM increase, about 800-900, the sounds goes away. I do not think it is drowned out by other noise, I really think it stops making that noise.

Also, as many of you know the hydraulic pump is driven off the back of the camshaft. At idle, when the engine is warm and the clicking is evident, lifting the 3-point stops the clicking instantly. Lower the 3-point, the clicking returns. Also, in some positions with various loads on the 3-point, the lift "pulsates" up and down a little as it is seeking the right position. During this pulsating, the clicking starts and stops, as the lift lowers and rises.

I have convinced myself that this clicking is backlash between the timing gears. When adjusting valves, turning the engine with a socket and ratchet on the crank bolt, I have heard the sound as a valve reaches maximum open, and starts to close. I have seen the valve "snap" as if the lifter is pushing the cam forward as it slides down the backside of the lobe. It does not snap all the way closed, just a little, then closes slowly as it normally would.

Now at 25 years the sound is getting much worse. I need to repair it. Any thoughts on this issue?

I have some sound files of the engine starting, after warming up, and the clicking stops when the 3 point is lifted. I thought I could post them here, but cannot figure it out right now. If I find a way, I will post them in the thread.
Hemmjo, I remember the song. Couldn't have told who it was done by though. As for your clicking, the first thing to do is, take a length of rubber hose or even a stick, like a dowel or broom stick and use it to pin point where the clicking is actually coming from and let the experts (not me) on here know.

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