My quest for "Grand" 3 point performance from my "economy" tractor. The L3400

[emmy71]

Re: My quest for "Grand" 3 point performance from my "economy" tractor. The L3400

Here it is, I got my tractor back today. I'm pleased but it's not at all the miracle that I'd hoped for.

YouTube - L3400 3 point New LSV New PCV one
YouTube - L3400 3 point New LSV New PCV two

I really don't get it. When I changed the LSV, it seemed that my hitch got jerkier but more responsive. Now that I have the new PCV, I've lost the responsiveness that I'd expected to carry through. I have to move the lever about 1/4" before the hitch moves. Some may suspect the "slop" EE_Bota has been referring too and may be right but before my LSV change my lever was responding in 1/4 inch increments, after it was responding almost instantly. Or at least it seemed that way.

The new PCV is much smoother than the old one, it doesn't necessarily appear that way in the video but if you focus on the fender you'll note that with the new PCV the tractor is pretty still even though there is some bounce with the BB. In the previous videos the entire tractor is shaking violently.

At this point I'm wondering if the LSV change has helped, hurt or is insignificant. I'm not ready to change it back though. If GMtb42 is still willing to go through with his test in spite of my lacking results, we may learn more. Although, I wouldn't blame him if he decided to mail those parts right back.

As for the PCV change, the mechanic said he spent most of his time removing and replacing all the shields. That it wasn't a big deal for him to replace the valve.

Still, more questions:

Why, is my tractor, with the same LSV, PCV and feed back linkage still jerky compared to the L3010?
Why did the extra sensitivity I seemed to gain with the LSV change go away with the new PCV?

The obvious answer would be the last remaining components of the system.
If I up my system pressure to 2400 psi, then I'll have a similar pressure to the L3010 (and a stronger loader). According to TractorData.com the L3010 has 7 gpm and the L3400 has 6.3 (My WSM says 6.31). I don't yet see how that works against me, a big part of our discussion has been about reducing flow. So, that covers the pump, I would think. The only other component that I can think of that would cause the L3400 to behave differently than the L3010 is the cylinder.

At this point we need more info. from someone with a WSM for the L3010. We need to know what size the L3010 3 point cylinder is, I think that means something to this puzzle. I'm close to duplicating the L3010's system in my L3400 and I need to know what's missing to make sense of this.

The L3400 Cylinder Bore is: 75mm/2.9528 inches.

My L3400 is in the 67XXX serial number range and I would say my hitch works about like yours does now.

Terry

 

[GMtb42]

Re: My quest for "Grand" 3 point performance from my "economy" tractor. The L3400

Getting spring and washer tomorrow if roads are not iced over , will do swap and give it a try , will post results !

 

[Harvest Moon]

Re: My quest for "Grand" 3 point performance from my "economy" tractor. The L3400

Thanks Emmy71 and canoetrpr, that makes me feel a bit better.

Teg, it really is only a 5 minute job, 10 allows for patience. I had just enough difficulty pulling the LSV out and forcing it back in that I'm tempted to quit while I'm ahead. Especially with Emmy71's and canoetrpr's accounts, it seems like I shouldn't expect much.

On another note, I got a PM from a very kind and helpful TBNer with the bore for the L3010. 90 mm +/- a few thousandths.

Bare with me, my math isn't what it used to be but when I calculate it, the flow rate is 10% slower in the L3400 and the cylinder (assuming the same stroke because it has the same connecting rod) is 17% smaller.

So, I'm seeing a net 7% difference between the two tractors. I can imagine that causing the difference in performance. If my math makes any engineering sense, slowing the flow by .5 GPM or to 5.8 GPM should match the two systems and their performance, if at the same rated pressure. EE_Bota, is this logical?

For those with an L2800, your tractor has a 6.5 GPM flow, and would be only about 7% slower so your hitches may be even jerkier.

 

[Harvest Moon]

Re: My quest for "Grand" 3 point performance from my "economy" tractor. The L3400

Getting spring and washer tomorrow if roads are not iced over , will do swap and give it a try , will post results !

GMtb42, not sure what to say? So far my results don't look to promising. I'd love to see how it works for you but hate to see you waist your time and money by my encouragement.

I started out on this quest confident, passionate and vocal about my thoughts and ideas. Now I'm somewhat humbled by my premature conclusions. I have no regrets (other that GMtb42's $10 or so) because my tractor is now a lot smoother and I think we are all much closer to a solution. If there is one that is worthwhile.

 

[GMtb42]

Re: My quest for "Grand" 3 point performance from my "economy" tractor. The L3400

GMtb42, not sure what to say? So far my results don't look to promising. I'd love to see how it works for you but hate to see you waist your time and money by my encouragement.

I started out on this quest confident, passionate and vocal about my thoughts and ideas. Now I'm somewhat humbled by my premature conclusions. I have no regrets (other that GMtb42's $10 or so) because my tractor is now a lot smoother and I think we are all much closer to a solution. If there is one that is worthwhile.

Well I watched the videos and it does look like what mine works like with the PCV change , so the LSV does not do much for the situation .
With the PCV it does get better , but still not smooth as I would like it , 1/4" movement is better than 1" and is usable .
No worry about the parts , will keep them around just in case .

 

[EE_Bota]

Re: My quest for "Grand" 3 point performance from my "economy" tractor. The L3400

Thanks Emmy71 and canoetrpr, that makes me feel a bit better.

Teg, it really is only a 5 minute job, 10 allows for patience. I had just enough difficulty pulling the LSV out and forcing it back in that I'm tempted to quit while I'm ahead. Especially with Emmy71's and canoetrpr's accounts, it seems like I shouldn't expect much.

On another note, I got a PM from a very kind and helpful TBNer with the bore for the L3010. 90 mm +/- a few thousandths.

Bare with me, my math isn't what it used to be but when I calculate it, the flow rate is 10% slower in the L3400 and the cylinder (assuming the same stroke because it has the same connecting rod) is 17% smaller.

So, I'm seeing a net 7% difference between the two tractors. I can imagine that causing the difference in performance. If my math makes any engineering sense, slowing the flow by .5 GPM or to 5.8 GPM should match the two systems and their performance, if at the same rated pressure. EE_Bota, is this logical?

For those with an L2800, your tractor has a 6.5 GPM flow, and would be only about 7% slower so your hitches may be even jerkier.

If I calculated it correctly

dia mm dia in radius in area sq in
90 3.54 1.77 9.86
75 2.95 1.48 6.85

(9.86/6.85) and it's inverse are ratios you can work with.

For a 6.85 sqin cylinder to move at the same speed as a 9.86 sqin cylinder, multiply the gpm by 6.85/9.86 = lesser gpm needed.

I have mislead you guys, but not on purpose. I have never modified a spool in my life. I was trying to use a rhetorical device to make my two overly long posts more engaging. I said "Lets' design a valve." "We can..." "I can..."

I have requested different spool cuttings from manufacturers...to cure various problems, but these are usually optional cuttings of off the shelf valves, and usually these are proportional valves. Once in a blue moon, the local distributor will modify a valve directly, but not often.

That not to say it can't be done. I'm a workaday engineer. I rarely get the chance to actually move metal. I have a lathe and a milling machine at home (cheap stuff) to compensate a little. I might would work on my own spool if I wanted / needed too, but I don't think I would if I had you guys problem. I would try the flow divider valve Canoe_ptr pointed out.

You know, in my BX2200, the very first thing the oil sees when it leaves the pump is a similar valve. My power steering and PTO work off the priority flow, but the lift and loader work off the excess flow.

 

[Harvest Moon]

Re: My quest for "Grand" 3 point performance from my "economy" tractor. The L3400

Thanks EE_Bota. I thought I had the math wrong, this time I came up with a 2 GPM reduction in flow, which seems more realistic. Probably still working it out wrong but I don't think it's that important.

The important thing is that there is something tangible here. All along I've been asking why the L3010 works better than the L3400 with the same valve. I think we finally have a supportable answer and I think canoetrpr nailed the solution a while back.

I don't feel mislead. "I can" can mean many things. Sure you could, that doesn't have to mean that you would, should or it would ever be a reasonable or practical solution for you to do. It's possible, that's fair.

So anyone want to speculate on how the L3010 PCV in the L3400 will respond to 4.3 GPM instead of the 7 GPM it works so smoothly with in the L3010? I get that the cylinder will move at a comparable rate in the different machines but will the valves performance be altered with less flow?

 

[Harvest Moon]

Re: My quest for "Grand" 3 point performance from my "economy" tractor. The L3400

On the flip side, is it possible that the lack of responsiveness in the position control lever correlates to the lower flow of the L3400? That if we had 7 GPM the hitch may rise a lot faster because of the smaller cylinder but the lever be more responsive as well? Thus, no more 1/4 inching? At least with the spring in the LSV?

Seems like the PCV valve I just replaced was a higher flow valve. Everything was amplified. Maybe reducing the flow to the old valve, with the spring in the LSV enhancing the responsiveness would result in a smooth hitch. Maybe with the new valve the machine doesn't produce enough flow to keep the valve active enough to respond to the lever immediately?

I must be loosing it. Next time I'm going to test the hitch before I sign.

 

[canoetrpr]

Re: My quest for "Grand" 3 point performance from my "economy" tractor. The L3400

Next time I'm going to test the hitch before I sign.

I don't think there is a single L3400/L2800 owner who is going to do any different!

 

[jeconn]

Re: My quest for "Grand" 3 point performance from my "economy" tractor. The L3400

You guys are persistent. Even though I don't have a 3400 anymore I watch this thread daily. Keep it up, you'll figure it out.