Can I Use a Double Acting Valve with a Singe Acting Cylinder?

[Iplayfarmer]

I posted about my new Terratrac GT30 crawler over in the "Projects" forum. Now that the initial enthusiasm and congratulations have worn off it's time to start the work of making it into what I need. The machine came to me with an electric hydraulic pump mounted behind the seat... Think dump trailer type pump. Not only is the wiring WAY wrong for it, but I'm sure the duty cycle would be wholly unfit for doing any real work. I'm going to re-build the hydraulic system with a real, engine driven pump and a real valve. I'm sure I'll need help along the way, so expect regular questions here.

The pump is from Surplus Center... 0.82 Cubic Inch. it should give me somewhere around 6-8 gpm at working engine RPM.
I have an old Jacobsen golf course reel mower that I'm scavenging parts from. It has a 3 spool valve, lots of hoses, filter, tank, etc.

I have two problems at present that I need to figure out:

1) The pump "does not have an out board bearing to support the shaft adequately under side load (pulley or chain drive) conditions." I was planning to belt drive off the fan belt, so I'll need to include some kind of bearing. I think I can figure this one out.

2) The real question that I have right now is that the lift cylinders on the sides of the loader are single acting. My valve is set up for double acting cylinders. How do I use a double acting valve on a single acting cylinder? Is it as easy as just blocking off the port that I'm not using on that spool of the valve?

 

[mrmikey]

You don't want to block the unused port in the valve, the pump would go over pressure relief every time you operated the valve in that direction. Plumb the unused port on the valve to tank, that way when you're moving the valve in that direction, the oil is just going thru the valve, out the extra valve port and right back to tank. Not the most efficient way to use a valve but you've got to use what you've got.
Put a filter of some sort on the unused port on the cylinder to keep dirt out, a rear end vent for example......Mike

 

[Industrial Toys]

Cute little CRITTER. What's it's name?

 

[Iplayfarmer]

Cute little CRITTER. What's it's name?

No name yet... Unless you count my satisfied chuckle every time someone asks me about it.

Maybe I'll put the kids to work thinking of a name.

 

[Iplayfarmer]

Next thought. I've been looking on ebay, and I'm surprised how cheap some of these large cylinders are...
Hydraulic Cylinder For Loader Welded Double Acting 2" Bore 32" Stroke 2x32 928879752151 | eBay

It may be worth it to just buy the double acting cylinders and have down pressure. Does anyone have experience with these cheap cylinders? Are the SAE8 fittings hard to find or work with?

 

[Industrial Toys]

Friend once leant me a 2 cyl Deere Dozer for the Summer. Great Fun. Amazing what it could push. No worry about thornes in Tires.

If you ever loose a track, you will wish you had down pressure.

 

[mrmikey]

SAE and JIC share the same thread pitch, just the seat angle is different, SAE is 45°, JIC is 37°. I think the SAE is more common for low pressure fittings. Me, I'd go with the JIC but to each his own. Saying that, you can get an adaptor to screw into the cylinder and change it to whatever you want to use for a hose end.

If you ever loose a track, you will wish you had down pressure.

Good point.......Mike

 

[TMGT]

SAE and JIC share the same thread pitch, just the seat angle is different, SAE is 45°, JIC is 37°. I think the SAE is more common for low pressure fittings. Me, I'd go with the JIC but to each his own. Saying that, you can get an adaptor to screw into the cylinder and change it to whatever you want to use for a hose end.

Good point.......Mike

That cylinder uses SAE o-ring fittings, no taper seal.

The SAE fittings are very common in cylinders, no problem finding fittings.

This is the style adaptor that is common for going from cylinder to hose.

 

[TMGT]

Thats a cool little crawler, I have a Oliver OC3 that I one day hope to restore.

On mine the hyd. pump is driven directly off the front of the crank, not sure if you'd be able to do that on yours. Mine has a heavy duty grill that allows a little more room for the pump.

 

[mrmikey]

That cylinder uses SAE o-ring fittings, no taper seal.

You are indeed correct, I never went to the page just assumed 45 deg seat. Proves what ***-u-me does LOL.
In that case, as TMGT said.............Mike

 

[Iplayfarmer]

Thats a cool little crawler, I have a Oliver OC3 that I one day hope to restore.

On mine the hyd. pump is driven directly off the front of the crank, not sure if you'd be able to do that on yours. Mine has a heavy duty grill that allows a little more room for the pump.
View attachment 678586

First of all, tell me more about your crawler... year? make? model? history as you know it? I assume everything runs well?

The original configuration on my crawler was also to drive the pump directly off the crank. Whatever coupler may have existed is no longer there, and some of the old bolts are sheared off in the holes of the crank pulley. I maybe could have put more thought into it before I bought a clockwise pump, but I'm committed now. I still think that a belt driven pump will be the right answer. I opened the UPS package yesterday and it looks like there is a race on the pump housing to put an outboard bearing if I can find one with a 14mm ID and a 24mm OD. I'm planning a trip to my local bearing shop today.

Does anyone have any more thoughts about the cheap eBay cylinders? That sure seems like the answer to my single acting cylinder problem unless these are known to have recurring problems.

 

[Iplayfarmer]

I also should mention that I got the valve pulled out of the reel mower last night. Here is a picture of it sitting on the track of the crawler. It just kind of looks like a dead squid right now.

 

[true temper]

I think the quality of the cylinders will be fine for your application, you wont put a lot of hours on that thing. But I think you need a larger bore you wont have near enough lifting power with a 2” bore. Them are sized for a garden mower. Get the double acting, you wont be sorry.

 

[Iplayfarmer]

I kind of struck out at the bearing place. The only bearings that they had of the right size were not sealed. They wouldn't last. I'm wondering if I'll end up with a bearing on the mounting plate and a shaft extension running back to the pump.

 

[CobyRupert]

You don't want to block the unused port in the valve, the pump would go over pressure relief every time you operated the valve in that direction. Plumb the unused port on the valve to tank, that way when you're moving the valve in that direction, the oil is just going thru the valve, out the extra valve port and right back to tank. Not the most efficient way to use a valve but you've got to use what you've got.
Put a filter of some sort on the unused port on the cylinder to keep dirt out, a rear end vent for example......Mike

Makes sense...but now I’m confused.
What happens when you plug in a single acting cylinder into 1 port of a tractor’s (2 port) SCV?
This is done all the time, but are you sending pump into relief when you retract the cylinder?

 

[Iplayfarmer]

So I refused to give up on the wild goose chase for the bearing. I found the right size in a bike shop in Leeds in the UK. For 8.73 British Pounds (a little over $12) it will be here around Christmas time. I'll proceed with the rest of the build for now, and if the bearing ends up being the wrong thing I'll figure out what plan B is when that time comes. Fingers crossed there's no ridiculous customs extortion fee.

 

[TMGT]

I order some machine parts from the UK (my vertical bandsaw is British) and haven't had any problems with customs or additional fees.

 

[TMGT]

I also should mention that I got the valve pulled out of the reel mower last night. Here is a picture of it sitting on the track of the crawler. It just kind of looks like a dead squid right now.

What model mower is that out of? I have a couple of Jacobson reel mowers for parts, if any of those valves are for the reel motors then they most likely won't work for the cylinders since they are open in neutral to allow the motors to spin down on their own.

 

[TMGT]

First of all, tell me more about your crawler... year? make? model? history as you know it? I assume everything runs well?

The original configuration on my crawler was also to drive the pump directly off the crank. Whatever coupler may have existed is no longer there, and some of the old bolts are sheared off in the holes of the crank pulley. I maybe could have put more thought into it before I bought a clockwise pump, but I'm committed now. I still think that a belt driven pump will be the right answer. I opened the UPS package yesterday and it looks like there is a race on the pump housing to put an outboard bearing if I can find one with a 14mm ID and a 24mm OD. I'm planning a trip to my local bearing shop today.

Does anyone have any more thoughts about the cheap eBay cylinders? That sure seems like the answer to my single acting cylinder problem unless these are known to have recurring problems.

Its a 1952 Oliver OC3, 42in track with an A.C. Anderson blade. I don't know much of its history, was bought from someone that was helping a widow sell off her late husband's equipment. Appears he was working on restoring it as there was a few peices that have been replaced.

I did get it running and drove it around a little when I first brought it home, that was 4years ago. Since then its been on the back burner unfortunately.

 

[mrmikey]

Makes sense...but now I’m confused.
What happens when you plug in a single acting cylinder into 1 port of a tractor’s (2 port) SCV?
This is done all the time, but are you sending pump into relief when you retract the cylinder?

Good question but I'm afraid I don't have the answer to that, I'm curious also..anyone?................Mike