I bought 2 new Chevy engines both started to have a rod knock.

One was a create 350 for my truck.

The other was a factory ZZ502.


The reason for the engine knocks, I am old school so I thought the thicker, was better so i used Kendal GT1 racing oil 20/50.

It turns out that modern engines a have tight clearances, so the thick oil did not get to all the moving pacts.

So now I only use factory recommended synthetic oil.

Otis