How much blow by is too much?

I don't know a thing about your tractor or it's condition, but here are just some thoughts.

My rule of thumb is: Because all engines must be able to breathe, and in differing amounts depending on the load & rpm, any amount of blow-by is permissible until it turns liquid. At that point, the engine is screamin' at you that something is very bad wrong.

It might just be something wrong with one of the components in the mechanical breathing characteristics of the engine, or otherwise, it is just old fashioned blow-by.

I know people get sick of me saying this, but if someone, somewhere along the line, has been in that engine and just threw in a new set of rings instead of doing the overhaul right, he has set you up for a disaster.

Ringing an engine without any work done on the cylinder wall is a surefire recipe for a short-lived engine failure. Likewise, just touching up the valves and not correcting the valve guides will have the same effect.

Hope this helps,

Allan

For looking pretty, very little.

For working, only when the tractor loses power to do the job you are attempting.

I have on old CAT D4D which has a lot of blowby (1 quart of oil per hour including that burnt) but it still pushes dirt.