I remember watching that Best Motoring video before, and thinking exactly the same things as I've just thought now. Engine oil is under so much more load and heat than gearbox oil.
His points of oil being pumped, cooled and cleaned..
The oil needs to travel greater distances within the engine and be at high pressure when it gets there, to create the film required to allow parts to spin. Gearbox bearings are not shells and film, they use various different types of race bearings that don't require oil for the spinny bits. What the fact the oil is pumped has got to do with longevity of the product, I don't know. Not much I suspect. Splash lubrication is adequate for race bearings, cogs, syncro rings and differentials.
The engine is a completely different beast in comparison to a gearbox, engine oil is heated through friction, but mainly because it's being actively heated through the sucking squeezing banging and blowing bit. Gearboxes don't have any sucking or banging inside them. Poor things. They don't know what they're missing.
The oil collects lots of contaminants from the cylinder walls through the combustion process and scraper rings on the pistons. There are also many more moving parts in an engine, leading to a greater risk of metal particles collecting and needing to be kept away from the very tight tolerances within an engine. Gearbox internals are in a sealed environment, without access to contaminants. They don't require filtering.
As knowledgeable as mr Ichishima is, I don't agree with him.
I agree with him on his opinion of flushing oils/fluids though, they are a terrible idea and should be banished.
Tsuchiya doesn't know much, as he openly states. But then why would he, he has a team of mechanics and engineers to do all that for him. He's a racing driver and a team manager. He also has plenty plenty money, and probably gets all of his consumables free. If tyres were free, I would bolt a fresh set on before every track day, and probably another set on at lunch. If my oil was free, I would change it more often, as it's not, I change it when I deem it necessary.
I don't know what you're worried about anyway, Honda's blow all their oil out the exhaust anyway. Hasn't the internet taught you anything?
I am not an engineer, nor am I an oil analyst. I could be completely wrong, it's happened before..once. What I do know is my engines have always been healthy and gone on to lead long and prosperous lives of the best kind of abuse. After all this, my engine is probably going to turn one of it's con rods into fusilli pasta on the next session.
