How many gallons before an engine becomes weaker.
 

How many gallons can an engine go through before it loses it power, and when does the power increase?

THanks!!

assuming you are in grup B : 30 minutes final + 3 x 5min qualifying

most power increase : usually your 3rd or 4th races

power decreasing : usually after 5th or 6th races

Complete engine rebuild or sell that engine after 5th or 6th races.

So I guess reaching 3 gallons is already considered lucky.

( I usually try to rotate the flywheel and feel the pinch. If it easy to twist, it means the engine is done. )

It is all about brand, model production serie and how you are using it. In the offroad people are getting 10 gallons and still going strong, in the onroad 1 gallon can happen and 4-5 gallon is possible. Cheaper engines do not have stronger materials....

You can lengthen the live a lot with pre-heating the engine and change the rod and check the bearings on time.