GM oil bath to paper filter conversion.

[Barn Owl]

I had wondered what was involved to change the oil bath filters to paper filters. When I dropped my filters I found that the previous owner had already done it. The conversion does not look very difficult. I almost decided to go back to the oil bath because I was getting quotes of $25 per paper filter! I finally found the paper for $16 each. After reading the many post on several boards I put paper ones back in. This bus spends some time on dirt roads and it seems that most say that paper is better for those conditions. Does anyone know of a study that settles this oil vs. paper debate? The oil level indicator was shortened and welded to 1 ¾ inches above the bowl bottom. The pan looks to have been inverted and placed on top of it. I felt that dirt could still get around the edges of the pan so I added aluminum tape to cover the holes that are in the center of the pan, and I painted the bowls because they were starting to rust. You can see how dirty the old filters were, you could not see the noon day sun through them. The previous owner ran it quite sometime with the exhaust blowing straight onto the ground and I think it stirred up a lot of dirt that got sucked up into the intake. The filters are Baldwin #PA1934.

[TomC]

I don't know of any equipment, truck or bus that uses anything but paper elements.  Make sure you have a restriction indicator on the intake side near the filter.  On off road equipment, they might have a pre filter that removes most of the big dust particles by centrifigal force.  Another really heavy duty type is the prefilter hooked to the exhaust pipe!  What happens is, there is a venturi installed in the exhaust pipe with a 1.5" opening on the suction side, and this is hooked into the pre filter with a long hose from the exhaust stack so when the engine is up in rpm, the exhaust coming through the venturi fitting will suck most of the dust and dirt from the prefilter and inject it into the exhaust stream and out the top of the stack.  Good Luck, TomC

[NCbob]

My old MC5A w/8V71 Detroit is equipped with (4) Donaldson turbine type (dry) air cleaners.  I was poking around in there the other day and pulled the elements.  One of the surprises I found was that the elements were stamped
'Donaldson'. 

I got to wondering (after I found I couldn't see sunlight through them) what the chances were that and of the previous owners would have taken the time and affort to hunt up a supplier who could furnish them with original equipment filters.  My answer?  Not a chance? 

This bus was built in 1968 and I suspect that these were the ORIGINAL elements.  God knows, they showed years of rust.  I went to NAPA and ordered 4 replacements...about $85 for the four. 

I took the bus to the shop today....about 120 miles over 3 pretty good mountains.  And while it didn't smoke prior to this ...pulling a steep grade...it didn't today either but it sure felt better when I needed to put my foot in it.  ;

It's sort of like ....the car seems to ride a little better after you leave the car wash! 

[belfert]

$25 for a paper air filter element is cheap compared to my bus!  I was charged $100 for the large Donaldson filter element in my bus.  Now, this was at a Detroit service center, so I probably got ripped off, but I didn't have much choice at the time.

Brian Elfert

[Barn Owl]

I failed to mention that the GM4106 takes four filters. K&N filters are $60 each but I wanted to see how long these last before I consider taking that route. I have a restriction indicator but I have not installed it. I haven’t decided how I want to do it yet. Has anyone done it to a GM? I could use some ideas, or guidance on how or where is the best place for the GM bus. I would love to see some photos if anyone has any. Thanks

[FloridaCliff]

Barnowl,

I don't believe the paper are any better than the oil bath, just easier to change.

My personal opinion is the oil bath are better.

But how often do you need to change your air filters?

If I wasn't running over 10K miles a year I would just keep whatever was in there.

Since its probably only a once a year job anyway.

Bets of luck

Cliff

[Stan]

Tom C: I think everyone uses paper filters becaause of labor costs to service oilbaths and the environmental laws on disposing of cleaning solvents.

NC bob: Your MC5A came from the factory with oilbath air cleaners. A previous owner has changed it to paper filters.

[TomC]

I just talked to K&N filters, and while I have a rather large K&N in my big rig and was happy with it, they do not make the large industrial strength filters anymore.  They had to custom make them by hand and was not cost effective.  Besides, we don't really put on enough miles to make the extra cost of the K&N worth it.  For example, my paper air filter for my truck was $85.00 a pop and had to replace it once a year.  The K&N replacement was $200.00 and just had to clean it and reoil it once a year-so in this case was worth it.  There has been some debate as to the filtering quality of the K&N-meaning they may let through small dust particles that a paper would catch.  Considering that a paper element costs around $50 and you might have to change it every 2 or 3 years, compared to a $10,000 overhaul, how much is that?  Good Luck, TomC