Hydraulic filter vs.Oil filter

Why?

Is there some factor you're looking at? Performance? Price? etc.?

Current oil filters do a good job and tend to be cheap, compared to engineering your own solution.

Filtering material is designed to remove particles down to a certain size. I have used hydraulic filters that were nothing more than stainless steel wire mesh, I have also used synthetic media filters that were able to remove debris from sealed containers of C-4 oil. Most hydraulic filters do not have bypass valves built into them. Many engine oil filters do. Dirty oil is better than NO oil when the flow requirements exceed the filter flow capability. What are you trying to accomplish?

Yes but not the other way around....................nor recommended. SO Don't!

$$$ cost of hyd over oil, hyd made to accept extreme pressures, oil not.

hyd likely to clog with motor oil usage, much finer filter ability, just to name a few. If your doing this because of free? access to hyd filters? ok I guess otherwise a very big waste of money and the likelyhood of clogging and..........................BYPASS and BYPASS relief PRESSURE. Huge difference that can cause lube failure/lack of.

Again, not worth the cost or risk of using or getting busted for "use" of company supplies if this is the case. Lose a 50K job for stealing a 10cent candy bar? ok ok .50$ candy bar.

Why do you want to make that change; what are your trying to achieve? Auto oil filters are designed to meet the specifications of the engine manufacturer regarding flow rate, pressure drop, bypass spring release tension and media pore size. You have no way of knowing whether the hydraulic oil filter complies with those specifications so I dont' recommend it.

It would be much better to use a high quality filter that is designed to meet the engine's specifications. Mobil 1 and Pure One are very good filters: Frams are junk. The key media criteria is the Beta ratio at a particular particle size, i.e. the ratio of particles of that size or larger downstream from the filter compared with the number of particles upstream from the filter. For example a Beta Ratio of 20 means there are 20 particles upstream to every one down stream. Most manufacturers of auto filters don't provide that data but you can usually obtain it from the technical people at the filter company. Curiously the companies that make oil filters for truck and industrial engines invariably provide Beta Ratios because the buyers insist on the data. The most damaging particles are those that are larger than the lubricant film thickness ~ 10-20 microns. There are very few full flow oil filters that will capture 10 micron particles without a huge pressure drop. That is why commerical and industrial engines invariably have a by-pass oil filter in addition to the usual full flow filter. The by-pass filter can remove particles down to 1 micron but the volume is so low and the pressure drop so large the oil that comes out of the by-pass filter is simply returned to the pan. If you really want to protect your engine install a by-pass 1 micron filter in addition to the filter designed for your engine.

Dennis Waller

Foreign Auto Service

Back in 87 I was faced with a transmission filter just blowing off of the mounting base on two different new trucks. This was on an Allison HD750DRD with an output retarder. After loosing a few filters, and not getting any satisfactory answers from the factories (truck builder, and Allison) I purchased a Pall synthetic media filter that was optional from Allison. It had very low restriction, combined with very fine filtering. I was very impressed with the performance of the filters. You can see their products at; http://www.pall.com/

High pressure hydraulic filters can be used in the pressure supply to valving, spool valves operated regularly may be OK with 10 micron filter, proportional control valves require 3 micron filtration. If the oil is not properly filtered the valves will "stick" and fail to operate properly.

If the oil is going thru manual valves to operate hydraulic cyclenders, the oil filter is usually at the reservoir in the return piping, which should be low/no pressure.

There are also "polishing filters" that are a filter pump loop from and dumping back into the reservoir, these may or may not run continuously.