Log splitter question

cwarrix · Nov 22, 2005

I hope this is the right forum, my splitter is not really a tractor attachment, but my question is related to hydraulics, so here goes...

I found a home made log splitter for a decent price, $250 over the summer. It is mounted on an old truck axel and has a hitch to tow it with. They used an 18HP lawn tractor (at least the front half) as a power unit. The pump is under the motor and connects directly to the shaft with no belts, etc. I mounted a different (safer and larger) fuel tank that I had left over from an old pontoon boat and was able to get it running in short time. Oh, had to add a new battery as well for the electric start.

I was able to split about 1.5 cords of wood, over a couple of days, and it started spitting hydraulic fluid out of the fill hole in the tank. The guy told me there was supposed to be a vent cap there? Anyway, I didn't seal it up and just stuck a plastic cup over the hole to prevent water from entering the tank. Any ideas why it would be doing this? It sprayed fluid out hard enough to knock the cup off and shoot about 10 feet in the air! One other thing... the hyd tank is about 2 gallons, does it need to be bigger to allow the fluid to cool more? I'm not very good with hydraulics so any ideas would be appreciated.

I'll try to snap a couple of pics of this beast tomorrow.

Thanks in advance!

MarlandS · Nov 22, 2005

It does sound like the tank is too small, I've got one set up virtually the same way but I have a 10 gallon tank with about 5 gallons of oil in it.

The only other thing I can think of is maybe the oil is getting saturated with air causing expansion. And if the cup was snug on the fill pipe, it caused pressure to build then when it finally blew , suction caused the oil to evacuate with the air. Is the suction line good or are there cracks that could be letting air into an otherwise full system?

Was the tank clear full and how much oil did you lose?

cwarrix · Nov 22, 2005

Thanks for the reply MarlandS, I have been watching eBay for a used tank that I could use for this. The plastic cup I stuck on there was actually the top off a spray can, it was just laying there to keep rain out, don't think it was tight enough to cause a seal. I think I lost quite a bit of fluid before I got it shut down. I didn't notice any bad cracks in the lines, none of them leak.

I'd like to get this in the barn and tear it down, clean it up, add a filter (has no filter now) and get it ready for next year. Oh, and add a bigger tank.

Thanks again for the help and ideas!
Chuck

cwarrix · Nov 23, 2005

One more question on the tank size... Is there a rule of thumb for sizing that I can use? I found a couple on eBay but not sure what size to use. Is bigger better, or is too big a problem? Also, do I need a filter on this type of setup?

Thanks again for the help.
Chuck

gizmo · Nov 23, 2005

Another thing that you can do is use a large diameter return line to the tank. This will reduce the velocity of the returning fluid.

rswyan · Nov 24, 2005

( Is there a rule of thumb for sizing that I can use? I found a couple on eBay but not sure what size to use. )
One gallon of reservoir capacity for each gallon of flow. With a two stage pump (dual flow rates) you'd probably be safe using the average of your flow rates.

( or is too big a problem? )
Nope - other than the expense of having to fill it /forums/images/graemlins/grin.gif

( lso, do I need a filter on this type of setup? )
Absolutely - if you want your components to last.

cwarrix · Nov 24, 2005

Thanks gizmo, my neighbor mentioned the same thing last night while we were talking. Sounds like I need a much bigger tank as well. I'll probably use the bigger return line when I replace the tank.

cwarrix · Nov 24, 2005

Thanks for the info rswyan. So, what I need to do first is figure out what flow rate the pump is and if it is a dual stage. Hopefully that info is on the pump under all the grease and grime. Sounds like a good Winter project to me. I need to get it in the barn where I can tear into it, replace the tank, maybe the lines, add a filter, maybe some paint to make it look pretty /forums/images/graemlins/smile.gif

I was also thinking about a pressure gauge somewhere in the system just to make sure I'm not exceeding any limits. I guess I could figure it out the hard way by finding the RPM of the motor, then checking the specs on the pump.... hmmm, a ten dollar gauge sounds easier /forums/images/graemlins/smile.gif

cwarrix · Nov 24, 2005

One more question about the tank... will an air compressor tank work? I'm assuming it should be metal, but didn't know if there were any other requirements. Since it is vented, I'm assumin there is no pressure either, right? I just need to draw the fluid from the bottom and return it to the top, sound right?

Thanks!
Chuck

turnkey4099 · Nov 24, 2005

( One more question about the tank... will an air compressor tank work? I'm assuming it should be metal, but didn't know if there were any other requirements. Since it is vented, I'm assumin there is no pressure either, right? I just need to draw the fluid from the bottom and return it to the top, sound right?

Thanks!
Chuck )

Yes, any good mechanically sound tank will work. It must have a vent cap. It must also not be filled full, leave room for expansion.

I noticed one thing. YOu say you bought it used and had some rehab to do on it. Did you change the hydraulic oil? If it was sitting with a an open vent or even a vented cap, it oculd have absorbed a considerable amount of water. If so, coupled with a small tank, the splitting activity could have heated it to the point of the water boiling.

I wouldn't run any used hydraulic equipment without a total replacement of all fluids first.

Harry K

moeh1 · Nov 24, 2005

Make sure your return line goes down into the tank far enough that the fluid covers it to prevent foaming.

cwarrix · Nov 25, 2005

I drained the tank and filled it back up with fresh fluid, but I didn't purge the lines and pump. Plus, I'm not sure if I got all of the fluid in the tank to be honest. Thanks for the tips, I'll get the pump info tomorrow and figure out what size tank I need. I found a couple of air compressor tanks (8 gal) on eBay close to home and something like $5. If I can get something like that to work, the price is certainly right!

Thanks Again! Happy Holidays!

cwarrix · Nov 25, 2005

Thanks Marty, is it better, or will it work, to just connect the return line to the bottom of the tank? Actually, I think that might be how it is now.

Happy Holidays!

rswyan · Nov 25, 2005

( I found a couple of air compressor tanks (8 gal) on eBay close to home and something like $5. If I can get something like that to work, the price is certainly right! )
If they are used be sure to clean out any rust that might be inside.

cwarrix · Nov 25, 2005

Good point about the rust, I didn't think of that. Guess that would cause me even more problems. The ebay ad says "no rust" but who knows. Here is the link if anyone is interested: web page

The small tank that is on it now is made from flat steel... maybe I could somebody that can weld better than me to weld an extension on the existing one. If I go with the compressor tank, I'll have to worry about fittings and all of that... Maybe I should bite the bullet and just buy a new tank like this one New Tank

There is a huge difference in price though $5 and no shipping or $60-$80 with shipping.

Decisions, decisions /forums/images/graemlins/smile.gif

kennyd · Nov 25, 2005

The SurplusCenter has some nice tanks, and they are a great company to deal with.

BigEddy · Nov 28, 2005

My bet is water in the oil. The water will sit under the oil until the oil temperature rises above boiling, then it will start to boil off. Because there is a layer of oil on top of it - it will spit and spurt terribly.

At the same time - I think the resevoir may be too small. Rule of thumb is 1 gal fluid for every gpm of the pump - A standard 8hp engine / pump combination is good for about 16gpm - but most commercial splitters seem to hold about 5gal fluid.

I'd put a filter in the line, change the fluids and make sure you have a good vent cap on it - then see how it goes. Worst you'd have to cool off for a while every hour or so. You can add a second resevoir in series instead of changing it out - if you keep them at the same level.

joetrausch · Nov 29, 2005

There is no mention of pump flow rate in gallons per minute. Since the engine is 18 hp, I think that your flow rate is much greater than 2 gpm. Minumum tank size is a ratio of 1/1 (1 gallon of tank size for each gallon per minute of pump flow). You probably have introduced air into the oil, which causes the oil volume in the tank to "expand" (bubbles in the oil). You need a larger tank. Get me the model number off of the hydraulic pump and I'll help you with this. And yes, you must have a vent in the fill cap on the reservoir or atmospheric pressure cannot push oil into the pump.

Anyway, please get back to me with the pump numbers, and we'll go from there. I assume the engine is running at 3000 rpm or slightly more, is that right?

Joe

Clyde · Nov 29, 2005

I have a log splitter with it's own engine, pump, and cylinder. Instead of hauling out the logs, I take the log splitter to them and split them into manageable chunks. The terrain isn't always even when I start splitting and this one time, I was setup with the reservoir filler cap/vent lower than rest of the unit. All was fine until I retracted the cylinder after splitting the piece of wood. Obviously air filled the reservoir with no way to escape and the oil blew off the vent cap and tossed it 10 foot in the air. The splitter was fairly new and obviously I had overfilled the reservoir with oil. Now I make certain that the filler cap is always higher than than the rest of the unit. So far - no problems. It is obviously a design flaw and I really don't know how to rectify it without expensive revisions. In the meantime I live with blocking the wheel up to make sure it is always higher than the other wheel. I hope this might help with possibly another idea.

Clyde

cwarrix · Nov 29, 2005

Thanks for all of the tips, it has given me a lot of ideas about what the problem could be. As for water in the oil, when I bought the splitter, it didn't have a cap on it. I drained the tank and refilled it, but I'm sure I didn't get everything out of the lines, etc. so that makes sense that it could have water still in there. I'll try to get the model number for joetrausch to check out, or maybe it will have the GPM on the pump somewhere. I haven't had time (during the daylight) to look at it lately. I also owe you guys some pictures of this ugly thing /forums/images/graemlins/smile.gif

I was looking online at splitters from TSC and noticed that most of the larger ones had 5-8 gallon resevoirs on them so I'm pretty sure I'm way undersized there. Still trying to find a low cost solution to a bigger tank. I was thinking of a new air compressor tank. I'd probably have to weld some fittings on it though. When you consider the time involved, I might just break down and buy a new resevoir from Northern. I looked at the stuff the other day online. Looks like I could get a new 10 gal tank, filter, and a strainer for a little over $100 plus shipping. Not bad I guess, I'd still have less than $400 in the whole thing. Can't touch a new one for that /forums/images/graemlins/smile.gif