Common sense says that preventing a majority of wear particles from entering the engine in the first place would be much more important
Oil filter crazy
- Thread starter Durdude
- Start date
Like I said both are important. There have been several studies posted here showing the correlation between oil filter efficiency and wear, I just thought that since you said the air filter was “far more important” perhaps there was a reason.
IMO, if you live in a dusty environment, or drive on a lot of (gravel) back roads, then it is more important to have a good air filter, over & above a premium oil filter, to prevent dusting the engine and killing the rings. Unfortunately the dust does a lot of damage BEFORE it ever makes it into the oil (& filter) to be captured. I kind of like having good ones of BOTH!
Of course having both a good air filter and a good oil filter matters. The oil filter matters more in the long run, especially in long OCIs ... while the air filter matters in more "real time". Maybe that's why some people don't believe an oil filter has any importance to engine health and longevity. 
If contamination does make it past the air filter, then the oil filter is also there so capture that source of contamination. Other internal engine sources of contamination (combustion blow-by, wear particles, etc) are only captured by the oil filter. Still waiting for that study that says cleaner oil doesn't result in less engine wear. 
If contamination does make it past the air filter, then the oil filter is also there so capture that source of contamination. Other internal engine sources of contamination (combustion blow-by, wear particles, etc) are only captured by the oil filter. Still waiting for that study that says cleaner oil doesn't result in less engine wear. Yes. I think air filter is important also. I run a Wix air filter but am noticing that my airbox deforms the gasket so im hoping it still seals properly. Anybody else have that problem?
Create a new thread in the maintenance section and post some pictures of the exact problem.
dnewton3
Staff member
When you get a chance, check out the Donaldson "Total Filtration" study (SAE 952557).
The term "far more important" is somewhat undefined and subjective, but I would agree that this study (and some others) seems to confirm that air filtration is probably more important than lube filter selection. Yes - all filters matter. But air filtration is paramount to reducing wear. Perhaps the most important thing to understand from the study that using a poor quality air filter (or ill-fitting air filter) will greatly increase wear. Also, overly-frequent air filter changes will "double" wear rates. I'm a BIG fan a leaving an air filter in service as long as practical; I use air intake vacuum gauges rather than guessing when to change an air filter.
The air filter is the most important filter . Take a fleet of engines and remove the oil filter and a same lot of engines and remove the air filter and run them to failure , all things equal and see which engines last the longest. I have posted this before but the service manager at work gave me the parts and filters to service a Diesel engine national account fork life. During the service I noticed the air filter was the wrong one. I called in and said I need to get the proper filter. The service manager swore it was the right one and I just wanted to get out of work. Ok I said I put the wrong air filter in and with in a month went to see about the engine smoking. We brought it into the shop and one of the shop guys rebuilt the engine and replaced the air filter again with the wrong one. About a month later I went out to check on the forklift smoking. The shop guy rebuilt the engine again and I told the shop guy that the filter was wrong and he installed the proper filter. All this this was about a 6 month period. The engines easily last 30,000 + Hours using Clark Lift filters .
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I've heard that air filters get more efficient with time, but will early changes and keeping a fresh filter in place really increase the wear rates?
dnewton3
Staff member
Yes - per that study I mentioned, they discovered that if you change the filter within the first 30% of it's lifespan capacity, the particulate that is passed in the "new" filter will result in a doubling of the wear in the engine! That's a direct (paraphrased) quote from the SAE study.
Further, when our member Jim Allen toured the Fram test labs, they talked about air filters. He said they told him that 90% of all particulate passed in the life of an air filter happens in the first 10% of it's lifeycle. I tried to find a link to the article but it's apparently been archived as it was in Trailer Life magazine; it went dormant a few years back.
Those two unrelated sources have convinced me that changing an air filter too often is a bad thing.
So now I need to know when to change my air filter. I always change it when it is brown....but not super dirty. Maybe we should start an air filter thread on when to change filters with pictures showing when people have changed them. ??
Plus a thread with pictures about your fit problem.
The bad stuff to be filtered in the oil entered through the air filter. Pretty commonly understood among those maintaining off-road equipment.
Not all of it. Apparently not pretty commonly understood.
^^^ Yeah, not all of it ... and no air filter is perfect. Anything that does get through, and also the debris being generated inside the engine while it's running can only be caught (or not) by the oil filter. Better oil filtration (and/or doing shorter OCIs) results in cleaner oil in the sump and less wear. Still waiting for the study that shows otherwise.
Not saying the oil filter isn’t important, but the sharp edged silica that makes it through a bad/missing air filter will cause much quicker, and more severe damage, than the carbon, sludge, and combustion/blowby byproducts that get through a bad or bypassing oil filter. There’s a reason why “dusting” is such a bad condition in the diesel & heavy equipment world-the damage happens before the oil filter even sees it!
Never mind, I found this:
www.machinerylubrication.com
How to Spot the Signs and Symptoms of Silica Contamination
After oxygen, silicon is the most abundant element in the earth’s crust. Silicon does not occur naturally in elemental form but rather combined with oxygen in a compound called silica (silicon...
www.machinerylubrication.com
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Most of the damage done by dust/dirt getting past the air filter is done in the cylinders and to the rings. Any that happens to blow-by the rings must go through the oil filter before it reaches any other part of the oiling system, except the oil pump. Like said before, the oil filter is the last step of defense to keep the oil clean.
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This guy ran a Purolator Boss filter (rated for 15K miles) for 3, 6K OCI without changing filter, so 18K on filter total without changing it, and sent oil to Blackstone for UOA every OCI--each UOA showed 0.2% insoluble which demonstrated the filter was still doing its job.
Insolubles isn't a good way to monitor filter efficiency. I've looked at Insolubles % vs PC data on UOAs, and there is no good correlation. An ISO particle count would be better.
