Well, this is one place I can reduce my maintenance cost a little.
Printable View
Well, this is one place I can reduce my maintenance cost a little.
I told myself when this thread started, here is one I wont be chiming in on because if I do these folks will think I'm nuts.
As many of you are aware Deb and I operated a tractor trailer in a local quarry for 12 years. Arguably a much dustier environment that we will ever experience in the bus.
Our truck had a Cat and when we sold it last year it had right at 1 million miles and without major engine repair of any type. I did a valve adjustment and new injectors at 550000 and that's it. When we got rid of it it would be around 1 gal of oil down at 10000 miles but I believe 90% of that was leaking.
The truck had an air filter restriction gauge with a red line at 25 inches of vacuum. Not only would I run them till, under full throttle and load, that gauge would hit the red line but then I would pull it and blow it out and reinstall it for a second go around. When I did pull it it was definitely noticeably HEAVIER than its new replacement and a couple of times I gathered up as much of the dirt i could and could easily fill a 2 pound coffee can with the silt I got out of it by banging and turning it on the concrete and blowing it out with air.
When reinstalled the gauge would barley move and the filter would then give me another half life compared to how long it took to get into the red initially.
I can't believe I have told this story but it needed to be said and there you have it.
The biggest difference I noticed when dirty is the turbo would not whistle as loudly as it would when clean but my manifold pressure would still be 24 at full throttle and I could not feel any lesser power.
The air filter in the bus is the one that was in there when we bought it. I blew it out and reinstalled it and I will get back to you when I replace it:o
There are a couple of different types of restriction gauges. One is on the canister itself and another is installed in the dash. Ours was in the dash and I do not know how or if I would have been able to safely exercise my technique without it.
On my 93 Newell I noticed low boost pressure when traveling thru Durango, CO (climbing hills). I located a new replacement air filter in Farmington, NM, installed it, and it made all the difference when climbing. The filter was really dirty. If I remember correctly the 8V92 didn't have an air fitler guage. My point here is - your engine will tell you when it is time to change the filter.
I have noticed, that it says "Do not blow out the bus air filter with and air gun". Maybe that is because they want you to buy a new one!
I had found a test document regarding air filters on large diesel engines a while back on the internet. It may have been a SAE study. On the sample engines where the filter was replaced early with relatively low mileage the oil samples showed significantly more silica (basically sand) and the cylinder walls showed more visible wear. They also tested the cotton cleanable filters (like a K&N that are coated with oil) and they let much more abrasives through, especially when new. Many of us tend to over service our busses, but I believe the air filter is one thing that works better when it is a little dirty. I take mine out @ each oil change and inspect it with a light as someone else had mentioned. We have been replacing ours at about 25-30K miles. I do not drive on any dirt or gravel roads, which would have a significant impact on the life of the filter.
Steve,
From what you have said, it makes it appear that smaller particles can go through the clean filter easier than through a dirty one. I wish I could go to the dump and get my old one back. At least, I know I shouldn't have to change this any time soon.
So does this mean nobody wants to take me up on my challenge at OKC?
BTW, if you do take yours out and find a bunch of dust and dirt in the bottom of the air cleaner housing it is dust and dirt that did not pass through the filter, but was blocked. When you shut the engine off the negative pressure downstream of the filter went to zero and the dirt was no longer held in place against the filter and fell from it.