Above you can see a number of popular kart racing. Look carefully and you can see that they do not mix.
- Do not take a chance on mixing any brand of oil with another.
- Do not use assembly lube.
- Assemble engine with the oil you are going to use to break it in with and race with.
- Do not break in engine on conventional motor oil and then switch to a "Kart Racing oil"
All it takes is a few seconds with out lubrication to start welding (metal transfer) from the rod to the crank pin. Once aluminum rod material starts to build up on the crank pin it's all over.
These simple test were done at 65* F. Who knows what will happen when you heat any of these concoctions up and stir it up violently in the engine.
Here's one brand of oil on a piece of clear lexan with another brand of oil on top of it. Notice that it creates it's own separate pool. There is a boundary between the two pools. If the two oils are compatible they will mix completely. If you are going to switch from one brand of oil to another (to be safe) you must completely flush the engine with a solvent that will cut (clean) the original oil.
This test and information was found on fastermotors.net