OK, Kind of an off-the-wall question. Does anyone know the pressures that can be generated with the power steering pump on these trucks? I've got a 67 F250, no power steering, but I am thinking of trying to drive some hydraulic devices with a power steering pump. I'm specifically looking at a hydraulic log splitter, so high pressures are going to be necessary.

Thanks

stu...

 

A test in a 72 manual shows 1200 psi minimum for a good pump.

 

 

[updated:LAST EDITED ON 15-Oct-02 AT 02:27 AM (EST)]I am pretty confident that there is an internal pressure relief valve in most power steering pumps. (At least there is one in my scout). I have heard of people replacing the spring on the relief valve to build up more pressure.

I would be very interested to hear if the ps pump works on a log splitter.

I think you multiply the area of the piston head in the hydraulic cylinder (square inches) by the PSI (pounds per square inch) to get the total force generated.

ie. For 3" cylinder

(Diameter / 2) ^ 2 * pi * psi

(1.5") ^ 2 * 3.1415 * 1200psi = 8482 Lbs of pressure

Sounds like you should use a bigger cylinder

5" cylinder = 23561 lbs

 

I dont know what kind of pressure they put out but i do know a chevy guy who built a little dump truck and used the power steering pump to pressure up the cylinders for the hoist. He just used some kind of valve system to divert the fluid and built a bigger reservoir.

 

If you could split the log with a single wedge & a sledge, then 1200 psi would be adequate with a 4" bore cylinder. I have the relief valve on my 4" bore log splitter set to 1250, and the only logs that stop it at this pressure are the ones with big knots. For these logs, I have a pressure intensifier on the splitter that will send about 5,000 psi to the cylinder at 1250 pump pressure. I rarely see over 2500 psi on the largest knots; but at only 1" thick, the splitting wedge acts more like a knife and actually cuts the knots in half.

Your biggest problem using a steering pump will not be the pressure, but the volume. My splitter uses an 11 Gallon Per Minute pump and strokes the 4" bore cylinder 24 inches in about 7 seconds. I doubt that steering pumps for these trucks flow more than 3 GPM max; probably more like 1 GPM at an idle. That is over a minute per split. Add at least another 30 seconds to retract the cylinder and a few seconds to position the log, and you are looking at about 5 minutes total just to quarter a round. It would take about 100 10" diameter logs 24" long to make a chord. We are talking about 8 hours just to split a chord of wood. Maybe someone here will be able to tell you how long a FE will idle on a gallon of gas, but something tells me that you will burn up about as much energy in gas as the energy you will get out of the wood.

If you have the NP435 tranny, a better alternative would be a PTO pump of addequate size and about a 5 gallon oil reservoir, asumeing you really want to power the splitter with the truck's engine.

 

Those are excellent points, and not ones I had thought about. I think I'll go back to the standalone power unit idea. Thanks for saving me a bunch of trouble.

stu...

 

[updated:LAST EDITED ON 16-Oct-02 AT 05:22 PM (EST)]The volume of your 24" x 4" cylinder should be
(4" dia/2)^2 * pi * 24" length = ~300cu inches or ~1.2 gallons

If the pump is 3gpm then that would be a pretty optimistic 2 strokes per minute. Yep! Pretty slow!


Just for reference:
4" cylinder at 1250psi ~ 15707 lbs of pressure.