Which air filter is best
- Thread starter papang
- Start date
Actually, the oil filter is pretty important because if the air filter isn't good then the only filter left to remove what gets by the air filter and into the oil is the oil filter. And besides, lots of debris in the oil is internally generated, so the air filter can't do anything about that to start with. So without a good functional air filter, the oil filter is definitely pretty important. And since nobody really knows how their air filter is actually doing, then running an efficient oil filter is insurance that it can make up for what the air filter may have failed to do.
A lack of a decent air filter is still going to cause excessive top ring and cylinder bore taper. The oil filter will never even get the chance to catch the dirt before the damage is done.
Of course the oil filter can't keep debris out of the cylinders - but oil with debris in it does lubricate the pistons, rings and cylinders ... and what keeps that clean - not the air filter. Debris in the cylinders can also get into the oil after it damages the cylinders - I wasn't claiming an oil filter could keep debris in the incoming air out of the cylinders, anyone who understands an ICE would know that.
And likewise, the air filter can't remove debris that is generated internally as the engine runs. Your previous comment basically says the oil filter isn't important if the air filter is good, which really isn't the case as I described. Even if the air filter is a "good one" in someone's mind, nobody knows what it's actually doing in real time because nobody has a real time upstream and down stream particle counter in their intake system. What the air filter lets by can only be removed by the oil filter if it gets into the oil. Kind of the main reason oil filters were invented around 100 years ago, lol.
A push lawn mower can run for hundreds of hours as long as it has a functional air filter. If the air filter falls off and it sucks up some dirt for an hour or 2 that engine will only last a few more hours, doesn't matter if the filter gets put back on or how many times the oil gets changed.
It's all top ring and cylinder bore erosion that ruins the engine. I get at least one lawnmower per year like that.
Project Farm did a review of air filters that may be useful.
Of course ... nobody is arguing that a good air filter isn't important or needed. But thinking that a good air filter means that the oil filter isn't important isn't seeing the whole story. There are two different things going on: 1) wear from dirty air and 2) wear from dirty oil. The air filter takes care of the dirty air and the oil filter takes care of the dirty oil, and it also takes care of anything the air filter allowed to get into the sump. Once debris is in the sump there are only two ways of getting rid of it: 1) filter it or 2) change the oil. Lawn mowers that don't have an oil filter should have the oil changed frequently, even it they have a good air filter. They shouldn't be ran for hundreds of hours on a sump of 16 oz with no oil filter. If so, they are wearing faster without an oil filter vs if they had an oil filter. And an engine that seems to "run good" for hundreds of hours doesn't mean it's not wearing out. Engines can wear out pretty far before they start showing symptoms of excessive wear.
Last edited by a moderator:
Mainly driven on paved roads. Definitely loaded up pretty good. Lots of sand sized particles, which is amazing on how they even got into the air filter. There's tons of debris on paved roads, even though you don't really see it while driving down the road.
