What paint colours are used on the engine bloc pic

I am trying to figure out the color of the engine bloc in the pic below.

I was wondering what shade of grey that is. Also the browns for the rust…

Woud like to reproduce that effect.

What would be the best technique

Any medium gray would do, especially since it is so dirtied up. What vehicle is it from? That isn’t really a good example since not everything would/should be grey.

For the rust, a couple different rusty brown colors will do.

The Kit is Thunder Models S-60 tractor.

I was planning to paint none engine parts russian green, but the engine in the metallic iron with grey

Hello!

As somebody with experience with soviet bloc motors I can tall you that most of these motors were not painted at all - I mean the cast parts, like the block and so on they were left in natural metal, because the gaskets leaked and everything would soon be covered in mixture of oil and dirt - and this is what you want to recreate here. I’d suggest painting everything flat medium gray and then going over that with more than one black wash, preferably somewhat glossy to show still wet oil in the recesses and more dry dirt on the exposed parts. Stamped metal parts might be painted gloss black when new, but that would quickly get dirty too.

Hope this helps - good luck with your build and have a nice day

Paweł