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Discussion Starter #1
I know there's been a number of discussions on quick-disconnects, but here I go again.

I had to re-do my snow-blade angle setup on the Bolens 1250. The red cylinder (3-1/2" stroke) that I initially used had a 3/4" and a 1/2" pin. The little 1/2" pin did not hold up against the frozen snow banks of course, and I decided to go with dual single-acting cylinders for the re-do. Unfortunately they were VERY slow so I rigged up a test fixture to check the pressure. Rather than dis-assembling the hoses to put a 'T' in-line, I decided to go with quick-disconnects.

Had always wondered what the Tractor Supply and OReilly Auto Parts snow plow quick couplers were, so I took a chance and bought a few. Turns out they were a perfect match for the leaky Pioneer 4050-2's (ebay - JD 316) that I had put on the Bolens a couple years back. Ended up replacing the front set. Next time the seat pan comes off, the rear set will be replaced as well.

Back to the SLOW cylinders. Pressure when the cylinders dead-end is 750 PSI which is on the high end of what the Eaton 12 puts out (from what I've been able to find). If anyone knows different, please let me know. Hoping the slow cylinders is just air in the lines. Double checked by connecting the dual-acting red cylinder and it moves plenty fast with no load. The new cylinders are 2-1/4 bore, 5-11/16" stroke. Haven't gotten back to it yet, but could it be that they are just very tight being brand new? Or a combination of being tight and air in the lines?

-Neil
 

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i dont have an answer for you but air should be worked out pretty quick. i know a bad quick connect can slow things down but i have limited hydraulics experience. hope someone has some better info for you

if you ever decide to get flush face couplers i got mine here pretty cheap
http://www.hoseandfittingsupply.com/product-p/ffset.htm
 

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The slow acting cyl could be because your pump is only moving 1-1/2 GPM or less.
 

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The air in your lines will not slow your cycl.down but will not be to kind to your pump..As Deerlop says your pump just isnt got gpm to do the job. Take your line from your pump and remove and put in pale and run the pump so as toget the air out if you have any in there,yhat should clear the air out of the system.
 

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I would think he would have the same problem with the red cylinder if it was a GPM problem. not trying to insult you but have you checked the fluid level after swapping cylinders around. Foamy or low?
 

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NSmith,

That is a nice setup you have. I don't know how slow is slow but could it be that you are pumping oil into the end of cylinders that don't have the rod inside? As you know, cylinders with the same volume of oil pushed into each end will be faster one direction than the other. Your current setup is the slow speed but more powerfull one.

Best,
BWS
 

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Discussion Starter #7
I kept a close eye on the fluid level when I attempted to bleed the lines. And nope, not insulted at all, glad to have any (and all) input.

Only one port on these cylinders (single-acting). Pushing one cylinder out in turn has to angle the blade and push the opposing cylinder in.

I was going to mess with it yesterday, unfortunately it was only 18 degrees or so out there. The Bolens was sitting outside and is plagued with the never-ending starter-generator issue (doesn't want to turn the engine over when the temp drops below 32 - a whole other issue that has been discussed a number of times on the forum).

Now that I've got extra quick-disconnects and hoses, I'm going to connect the cylinders together and see if I can turn the blade by hand. Should be able to get some good leverage on it with the 54" blade. (assuming I can get it started today and moved into the garage where it's a bit warmer) Then I'll move on to connecting the cylinders to the control valve that operates the 3-pt cylinder (a standard Bolens 2" bore with 6" stroke). Again, the add-on 3-pt cylinder and the factory mid-mount cylinder (tied to the push-arms that lift the blade) both work perfectly and are plenty fast.

Could very well be my perception/expectation is just way off. The pivot point of the blade is 8" from the cylinder connection point. And the 3-pt setup is only 4". So common sense tells me the blade has no choice but to move slower, but when I only watch the travel of the cylinder itself, my perception is that the single-acting is noticeably slower than the dual-acting. Would the extra 1/4" in bore size make that much of a difference?

Thanks again for the input
-Neil
 

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Neil,

Is the red dual-acting cylinder also 2.5" bore?
If so, then the single-acting cylinder should move at the same speed, since it requires the same displacement of fluid to move the same distance.
A 2.5" bore has 4.9 sq. inches or piston area, or 4.9 cubic inches per inch of travel of fluid requirement.

I set my 1886 up the same way, but used 1.5" bore cylinders, which move quite quickly.


These are the cylinders I used:
https://www.surpluscenter.com/item.asp?item=9-7878&catname=hydraulic

A 1.5" piston has 1.76 square inches of piston area, so it requires only 1.76 cubic inches of fluid per inch of travel.

Granted the 2.5" is going to have much more push power, since the PSI multiplied by square inches of piston equals the thrust pressure, but it doesn't need that much to rotate a blade.
At 500psi, the 2.5" cylinder will generate 2450#, while the 1.5" bore will generate only 880#

The 1.5" cylinder will move 2.78 times as fast as the 2.5" cylinder at the same GPM.

It also appears to me that your cylinder rods connect to the plow farther from the pivot than mine do. That makes a huge difference in pivot speed too, since the amount of cylinder travel required per degree of rotation is much greater.
 

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Discussion Starter #9
Picked up a little 200 watt magnetic heater Sunday afternoon, stuck it to the bottom of the engine and got it started and back in the garage. And of course it got up into the low 60's today, oh well, another useful "tool" for the collection.

The red cylinder is a 2" bore and the new cylinders are 2-1/4".

I get 7 days in a row off so will get to play with it again this weekend after I recover from Turkey Day.

-Neil
 

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Ok. Well, the 2" bore will have 3.14 sq inches of piston, while the 2.25" bore will have 4.91.
3.14 cubic inches of fluid per inch of travel vs. 4.91 cubic inches. That is 1.56 times the displacement, which should result in 33% slower travel.
 

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Discussion Starter #12
Got back out there this a.m. and swapped things around to get one of the stock Bolens control valves on the single-acting cylinders. Speed was the same, so was able to rule out the dual spool control valve being bad.

Put it all back together and re-timed everything (on-board dual-acting 2" bore x 6" stroke vs single-acting 2.25" bore x 5-11/16" stroke). Then plugged the numbers into the calculator on the following web-site for comparison.

http://www.baumhydraulics.com/calculators/cyl_speed.htm

Standard Bolens dual-acting cylinder (1.5 gpm gave a result very close to the 3.3 sec extend time so using this as a "known")
Pump GPM Cylinder Bore(inch) Stroke (inch) Rod Diameter (inch)
1.5 2 6 1

Extend speed= 1.8 inch/sec
Extend Time= 3.3 sec.


Standard Bolens dual-acting cylinder (times this at approx 5.5 sec rather than the calculated 4 sec)
Pump GPM Cylinder Bore(inch) Stroke (inch) Rod Diameter (inch)
1.5 2.25 6 1.5

Extend speed= 1.5 inch/sec
Extend Time= 4 sec.


The system is plumbed with 3/8" steel line and hoses except where it squeezes down to the 1/4" quick disconnects and hoses up front. Would this cause the 1.5+ second discrepancy?

Thanks
-Neil
 

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Neil and Steevo,

Thanks to both of you guys for posting this information. This is very encouraging and helpful for guys like me who would like to convert their manual angle plow to power angle.

You have both given the rest of us plenty to think about.

Happy Holidays!
 

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Ok. Well, the 2" bore will have 3.14 sq inches of piston, while the 2.25" bore will have 4.91.
3.14 cubic inches of fluid per inch of travel vs. 4.91 cubic inches. That is 1.56 times the displacement, which should result in 33% slower travel.
the 2 1/4 cylinder has 3.98 sq inches of surface area, so should move at about 80% of the 2"er

I believe you calculated using 1.25 for the Radius. Should be 1.125
 

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the 2 1/4 cylinder has 3.98 sq inches of surface area, so should move at about 80% of the 2"er

I believe you calculated using 1.25 for the Radius. Should be 1.125
You got me!
as Rick Perry would say . . . Ooops.
 

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My question for Neil is: How well do the quick disconnect seal? When you disconnect them, do they seal well and not leak?
The ones I got from Surplus Center seep, even the ones on the plow, when it is off the tractor and has no pressure.
 

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Discussion Starter #17
I installed the new pair of couplers on the rear last week, and I disconnected the blade angle cylinders this a.m. after reading Steevo's post. Just now went out and checked, so far so good (no drips).

I'm in need of dust caps now however ($3+ each). Wondering if I would have been better off with the flush face couplers that hammerdwn20 suggested.

-Neil
 

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Back to the SLOW cylinders. Pressure when the cylinders dead-end is 750 PSI which is on the high end of what the Eaton 12 puts out (from what I've been able to find). -Neil
The PRESSURE has just about zero relevence to cylinder speed. VOLUME is what determines how fast the load moves, pressure is what determines how much load can be moved.

As others have noted, there is a huge increase in flow (volume) required to keep the speed constant for only a small increase in cyl. dia. There's no way around the constraints of geometry. None of these small tractors make much flow so patience is necessary. Because they pull the hydraulic flow off the charge pump for the hydro drive there isn't even a good(read "easy and cheap") way to get more bang, no matter how many bucks you could apply.
 

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Discussion Starter #19
Thanks for the info Alan. I'll live with it this Winter and find some smaller cylinders for another Summer project next year. The 2-1/4 cylinders should make for a good project for the Ford 1700 (5.3 gpm according to the spec sheet), rear blade angle setup maybe?

-Neil
 
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