Intermittent lifter noise Craftsman LT 1000

[PTMD59*]

While it could be lifter with a leak so it runs down from time to time, they are generally very reliable.
The cam has a decompressor mechanism built into the bottom of it.
The rivets wear / break / come out then the little lever bounces around inside the engine till it gets jambed into something when everything comes to a rather abrupt stop.
The abrupt stop has a habit of knocking teeth off gear wheels or even braking the conrod.
Because the cam runs at 1/2 crank speeds, it sounds like a valve problem.
They pull apart veryeasily and the factory service manual is a free download directly from Kohler. What could be easier ?

Would the situation that you've described cause the lifter noise to occur intermittently? The noise that I am hearing does not occur when temperatures are anything above 65 degrees Fahrenheit. Throughout the summer months...May thru August, this engine is completely void of any lifter noise, etc.

That is why I was thinking about switching from Kohler conventional oil to a synthetic blend oil.

If something was broken, or loose internally ..wouldn't I be hearing unwanted noise regularly?

Thanks