View Full Version : oil filter vrs hydrolic filter

03-11-2010, 01:05 AM
My neighbor has been using an oil filter on his log spliter because it costs 6 dollers vrs 36 for the OEM filter. the first one lasted 4 months before it blew out around the second one only a couple of cords worth over a couple of weeks the rubber gasket was blown out of its slot and maybe my problem is I tightened it as hard as I could be hand not having a filter wrench.
the first one that failed seemed to be pretty crunched inside

so question is are presures to high to use an oil filter? are the filters different , ie the oil filter finer so it clogs sooner? is the flow of 16 gallons a minute ( guessing as the machine is a 9 horse power 30 ton force cylinder of 5 inch dia by 24 stroke) am also guessing it is a two stage pump that running free it pumps 16 gallons per minutes at less than 1000 psi but then when spliting wood it " gears down" and produces about 5 gallons per minute at 2700 psi/ does this sound right? could the shock as it changes output be what is blowing out the filter gasket? since that is when it seems to happen.

thankyou for information
ps i was thinking that their should not be as high pressure on the return line and that the control valve is wearing out but logically thinking it through when the valve is in newtrail the high pressure flow from the pump just goes right back through the filter into the strorge tank

03-11-2010, 01:47 AM
$6 vs $36......there's your answer right there.

I'm not a hydraulics expert (I woz but a lowly operator) and hopefully an expert will be along shortly......in the meantime....hydraulic systems are their oil.....keep it clean.

03-11-2010, 03:15 AM
Besides the huge pressure difference, perhaps a micron difference?

Zane Lewis
03-11-2010, 03:25 AM
As said before. Hydraulic oil should alway look clean, engine oil does not, it fills up up with carbon etc. This passes through a standard oil filter. Without knowing if we are talkin about spin on can or a tank top filter a Hydraulic return filter will generally handle a max of 150psi.
With a log splitter as with any press type application you can get a huge pressure/flow spike down the return line when the ram releases with the timber breaking. this can produce a momentry flow much higher than the pump output. Also with a ram due to the unequal volumes each side you can get a lot more oil out one side than is going in the other.
While you may not need to go back to the OEM element always get a reconised brand named hydraulic filter. Cheap ones are surface media Cellulose (Paper) media typically 10 mic nominal, 25 mic absolute. Then you move to MicroGlass depth media elements say 10 mc Absolute. Either are suitable for a log spliter. The difference is the dirt holding capacity.

Anything automotive has no place in a hydraulic circuit.

03-13-2010, 01:50 AM
Thankyou Zane
it was the spin on can type of filter

thankyou for increasing my knowelege bacause it did not occure to me about the pressure /flow spike when the wood pops apart . I wish not I could remember when the first time it blew what was happening but this last time it bley as I was railing the wedge with a log jamed on and it had just contacked the " log shucker" a U shaped piece of metal to force logs off the splitting wedge

Ive no way of knowing what the force of the hydro when the valve is in nuteral and the cylinder is not moving but a whole lot of hydro sprayed out in the time it took me to run around the machine

George Ray
03-13-2010, 05:06 AM
hydraulic filter:

Cheap ones are surface media Cellulose (Paper) media typically 10 mic nominal, 25 mic absolute.
If that is hydraulic spec, then what is automotive filter particle size spec?

Zane Lewis
03-16-2010, 02:39 AM
Don't know about automotive filtration.

I do know that Hyd oil should look clean and clear. Yellowing is oxidation and breakdown of oil. Filtration varies with system complexity. Servo valves need 2-5 mic filtration which can start to strip Zinc a High pressure anti wear additive so it's all a compromize between different system requirments. Gerotor Motors need lot of anti wear servo's don't.
Crude systems such as log splitters with gear pumps can get away with 25mic nominal. Most systems use 10 mic absolute.

Hydraulic systems should not be subject to carbon build up. That can suggest you have issues with air bubbles forming and then ignighting (sp) in a form of dieseling.
ie take a mix of air and oil vapor and compress it 200:1 and it will go bang.

03-16-2010, 09:51 AM
Automotive filters generally have a bypass valve to protect the engine. Not good in a hydraulic system.
If there is enough particulate the automotive filter will bypass to protect the engine from catastrophic bearing failure but the same filter will cause catastrophic failure in a hydraulic system and there goes your pump!$$$
The oil types will have more or less anti-foaming additives to help prevent micro-dieseling.
The generic multi-purpose hydraulic oils (tractor fluid) used in systems with torque convertors/shuttle transmisions have friction modifiers that often darken the color.
I have repaired log splitters that had enough algae in the oil to immediately clog any filter. They often sit around for a year between uses!
The algae looks the same as the stuff that grows in diesel fuel, it's pretty spooky looking. Sort of like jello...

03-16-2010, 10:20 AM
Could there be biocides for hydraulic fluid like there are for diesel?

03-16-2010, 10:39 AM
IMHO biocides should not be necessary - as changing the fluid should obviate the need.

I'd also never use an oil filter in a hydraulic system. Penny wise, pound foolish.

Change the hydraulic fluid every couple of years & change the filter at the same time. $50 total? $75? Well worth it.