Air Filter Modification Question

[rtimgray]

I'm in the process of replacing the air filter assembly on my old Case 310 dozer. It originally had an oil bath filter (great big canister with a wire mesh in it and the bottom has a detachable cup that is filled with oil, just in case anyone is unfamiliar). (Edit: because it leaked and was becoming a water bath filter).

I looked up what type of "paper element" filters went with my dozer or other vehicles with the same engine, and it seems as though the required CFM is somewhere around 125 to 150. So I went off to the junkyard and looked until I found an air filter assembly off of a Nissan forklift - it turns out its filter flows up to 275 CFM, so I think I'm good.

I can physically fit the filter assembly in close to the same place as the old one, but it is much smaller. The old assembly was bascially an 8" diameter by 18" tall cylinder, mounted vertically. The new unit is about 8" diameter but only about 10" tall, again mounted vertically.

The old unit protruded through the hood of the dozer (through a hole - this was factory design). The new unit will fit under the hood and I would like to cover up the hole and weld it shut. This would make a nicer looking hood and one less thing to get hit by branches when I'm clearing treees.

The old assembly had the precleaner intake (a little gizmo that lookes like a mushroom with screen around it) mounted on top of the old filter assembly. Of course, it was out in the open air. The new assembly has it's intake coming out the side of the filter assembly, so the precleaner would actually be drawing air from beneath the hood, if I don't change anything. So I say all of the above the pose this question: can the precleaner draw air from beneath the hood, or does it need to protrude above the hood.

The dozer's engine is open on each side, so there is nothing to restrict air flow over and above the engine to where the new air filter assembly intake would be. I can't imagine that there would be a problem putting the precleaner under the hood, but thought that I could run it by the brain trust first.

Thanks for your help.

 

[Gary Fowler]

There shouldnt be a problem with that other than it will be drawing in a lot of hot air from the engine which will marginally reduce your HP. Cold air expands more when mixed with combustion gases and therefore gives more power than hot air mix. You will also likely be in a dustier environment down low versus up high like the original equipment and will require more frequent cleaning of the filter.
All manufacturers (except maybe the Kubota RTV guys) put the air intake where it can draw in the freshest and coolest air but that doesnt mean that you cant use yours where it is.

 

[rtimgray]

Good thought on the cool vs. warmer air - I might just put a 90 elbow on and run the precleaner up through a smaller hole in the hood.

Thanks.

 

[Soundguy]

IMHO.. I wouldn't convert from the very efficient oil bath air filter to a paper element style.. but that's your call.

I'd fix the existing unit that leaks and use it... engine made it this long with that style of filter.. must be junk and not function correctly right??

soundguy

 

[rtimgray]

The engine was also available with a paper element; so at some point, just a couple of years after my dozer was made, Case (the manufacturer) chose to change to the (more inefficient) paper element; I'm assuming oil bath was probably more "in style" at the time. In later model years, my same unit was available with a paper element later in it's life. I could not find a complete unit to purchase, so I had to improvise.

The existing unit is basically beyond repair - the cannister itself is cracked and damaged all around it -that is where the water is getting in - a lot of the wire mesh is also missing.

I've heard that oil bath filters are better - then why do manufacturer's not use them very much any more? (I'm asking - I really don't have any idea). Some of my older equipment works fine with the oil bath filters, but the filters themselves are in good shape.

Thanks.

 

[Soundguy]

So how much money do you think the dealer makes selling you a half quart of oil for your oil cup, vs selling you a 30-60$ dry element, or dry element(s) for the dual element filters.

yep.. was a time saver for the manufacturers in servicing, and a way to make money selling you a consumable.

that filter media metalic floss is very available and if the cannister is metal.. it can be repaired or re-fabricated...

soundguy

 

[rtimgray]

I agree with you 110% on the cost of a paper filter vs. oil bath, and I'm sure that is a motivating factor.

The filter assembly that I purchased from the junkyard cost $20. A new Wix filter for it costs $11. There is no way that I can repair/have the unit repaired for anywhere near this amount. I might have to buy one filter per year. The new unit will allow for plenty of CFM to the engine, through a modern filter element. If I were interested in keeping the dozer even somewhat original, your idea would be valid - it's just not for me.

Thanks.

 

[moeh1]

You may /may not have an issue getting the carb tuned with the paper filter. My old case 310 (upflow carb?) wouldn't run less than full choke with the oil bath intake hose off. I'm not sure the paper element has similar amount of "restriction".

 

[rtimgray]

Mine's a diesel - sorry for leaving that out.

 

[Soundguy]

I agree with you 110% on the cost of a paper filter vs. oil bath, and I'm sure that is a motivating factor.

The filter assembly that I purchased from the junkyard cost $20. A new Wix filter for it costs $11. There is no way that I can repair/have the unit repaired for anywhere near this amount. I might have to buy one filter per year. The new unit will allow for plenty of CFM to the engine, through a modern filter element. If I were interested in keeping the dozer even somewhat original, your idea would be valid - it's just not for me.

Thanks.

considering the life of the machine, and that filter element cost when dirty, I can't imagine not being able to completely fab up a new canister for the price of a few years of filters.

considering if you hit a real dirty dusty job, you can clean an oil bath and renew every 6 hours if needed, for about 1.30$ of oil.. vs 11$ per change on the air filter.

anyway.. Like I said.. your machine, ok to do whatever you want to do with it. For sure it's going to be GOOD to have a filter on it, even if non oem. unfiltered air is bad, filtered air is good. if it's enough air flow, and the filtration media is the correct size..e tc. should be ok.

soundguy