I Still Hate My Tractor

[k0ua]

I am not going to comment one way or another about Freds modifications, as I don't have the experience to make any meaningful contribution. but something he said did make me do a test today as I was out pushing snow.

Fred mentioned that he saw a tremendous drop in RPM going up a hill when he raised or sent his hydraulic pump into relief.

So I went up the steepest hill I have, and let me tell you it is plenty steep in MED with my 3 speed hydrostat and tried it at various RPM's and this is what I got. All of these tests are with the hydro pedal mashed to the floor.

At about 2400 when I raised the loader the tach would drop about 50 rpm and regain 2400 almost instantly (govenor kick in I guess). When I deadheaded the pump by pulling into curl all the way. it would drop about 100 and stay there.

At 1700 when I would raise the loader the tach would drop about 50 to 75 and regain 1700 When deadheaded the pump it would drop about 175 and try to regain some back. I did not hold it very long, as I don't like to actually deadhead a pump.

Overall the drops in RPM were very minimal and except for sound note of the engine you could hardly tell it.

My 38 gross horsepower Kioti is sure not the same engine, but the tractor with loaded tires, my 850 lbs of ballast on the back, and loader is just under 6500 I believe. This may or may not be pretty close to Freds Tractor, but I am thinking pretty close. I am no mechanic either, but I am still having trouble understanding such a big drop on Freds machine unless the governor is not working right. I know that hydrostatic transmission, have much greater losses than a gear machine but guys they are not that much. I wish I could help and offer some assistance, but unfortunately I cannot. Carry on, good luck.

James K0UA

 

[ovrszd]

I am not going to comment one way or another about Freds modifications, as I don't have the experience to make any meaningful contribution. but something he said did make me do a test today as I was out pushing snow.

Fred mentioned that he saw a tremendous drop in RPM going up a hill when he raised or sent his hydraulic pump into relief.

So I went up the steepest hill I have, and let me tell you it is plenty steep in MED with my 3 speed hydrostat and tried it at various RPM's and this is what I got. All of these tests are with the hydro pedal mashed to the floor.

At about 2400 when I raised the loader the tach would drop about 50 rpm and regain 2400 almost instantly (govenor kick in I guess). When I deadheaded the pump by pulling into curl all the way. it would drop about 100 and stay there.

At 1700 when I would raise the loader the tach would drop about 50 to 75 and regain 1700 When deadheaded the pump it would drop about 175 and try to regain some back. I did not hold it very long, as I don't like to actually deadhead a pump.

Overall the drops in RPM were very minimal and except for sound note of the engine you could hardly tell it.

My 38 gross horsepower Kioti is sure not the same engine, but the tractor with loaded tires, my 850 lbs of ballast on the back, and loader is just under 6500 I believe. This may or may not be pretty close to Freds Tractor, but I am thinking pretty close. I am no mechanic either, but I am still having trouble understanding such a big drop on Freds machine unless the governor is not working right. I know that hydrostatic transmission, have much greater losses than a gear machine but guys they are not that much. I wish I could help and offer some assistance, but unfortunately I cannot. Carry on, good luck.

James K0UA

Good test James. Wish you had tried it at something closer to 1/2 throttle rather than 3/4 throttle. Maybe another test at 1500, then 1200, then 1000. I'll run a test on my Brother's L3240 in a couple days and report findings.

 

[k0ua]

Good test James. Wish you had tried it at something closer to 1/2 throttle rather than 3/4 throttle. Maybe another test at 1500, then 1200, then 1000. I'll run a test on my Brother's L3240 in a couple days and report findings.

I am sure it will drop more with lower throttle settings. but Heck I would never go up that hill at less than 1700, especially in Medium range.. Now if I was in HI range, it might of stalled.

 

[Chilly807]

A mechanical governor will drop rpm slightly as the engine is loaded, and will maintain that new rpm setting within the capability of the engine. This is not a result of an overload condition, simply an inherent trait of a mechanical governor. To the best of my knowledge, there's no way around that (this is what I do for a living, btw). In most cases it's not a problem anyway, and in the situations where you need more accurate speed control there are hydraulic or electronic governors that can be adjusted for zero speed droop.
An overload condition is quite different, as the speed drop is not controlled, and the engine will actually stall if the excess load is not removed or reduced. With an overloaded engine, the fuel rack goes to it's maximum position and stays there until load is reduced, and there's usually black exhaust smoke, which is also present in cases of air starvation.
When Fred increased the fuel setting, the engine couldn't burn the extra fuel efficiently, so it dumped it out the exhaust as black smoke, essentially unburnt fuel.

Sean

 

[buickanddeere]

I'm concerned that our resident OCD tinkerer has tweaked so many items on the tractor that finding a baseline to measure from will be difficult.
As previously stated if the engine really is down on power. It's either due to cam timing, injection timing or some strange phantom assembly error. And/or a heavy parasitic load from a hydraulic pump fighting a relief valve.
iirc the typical diesel opens the intake valve somewhere between 15 degrees prior to TDC to TDC. If measuring modern cam timing at 50 thou lift then of course those degrees change.
Any access to a thermal gun to check exhaust temps on all cylinders? This engine could have a cylinder riding along doing nothing?

 

[sd455dan]

Fred, This might help some.
Compression test in Bobcat specs. fall in line with your findings:

View attachment 349270

Here is valve timing the V2003T;
View attachment 349271

Here is valve timing on the V2203;
View attachment 349272

Injection timing on both is 18 BTDC.


Turbo will definitely add more power but might as well check everything while you are at it.

Thanks for posting this information , it is helpful looks like they added a small amount of duration on the turbo cam...

 

[the old grind]

A governor trying to keep rpm up would add fuel & should make more smoke doing it, no? (.. clean burning at most speeds when unloaded? ..)

Fred's intake opening event should align with whether factory specs consider cam rotation before the .050" he timed at. Show me 30^ of 'ramp' (take up lash) and/or to get that .050", and Fred's '15^ after' could be someone's '15^ before'. (Cam is ok if so?) Gotta be sure where lobe center is and where it's best measured in crankshaft degrees.

I've seen oil 'coolers' that were just long lines out into the airstream somewhere and back vs finned or thru a core. See the boneyard for odd shaped/sized coolers/cores with various inlet/outlet openings. Inter-cooler volume can add to lag (think Kubo robo-throttle) so he'd want to keep inlet air temps down as compactly as efficiently. IMO it'd be great to have that.

Fred, I was just explaining old-school 'doodlebug' to a young friend. With cab on & hood off the look would be there for ya during all the development/test work, .. and alterations. Would put any bodywork on no matter what/where add-ons do for now. (Didn't really think you'd start choppin' just yet. ) 'Remoting' can add to plumbing but also ease servicing. Can you get going with a cheapo point & shoot digital temp gauge, like if you're rtr & still shopping for a better monitoring setup? (don't know which happens first ..)

 

[milkman636]

Thanks for posting this information , it is helpful looks like they added a small amount of duration on the turbo cam...

I was thinking a new camshaft might be required myself.

 

[crazyal]

Look forward to seeing the turbo in operation once it's complete. I think it's a cool mod to do. There's no question you haven't been happy with your tractor, maybe this will change that. Maybe along the way you'll solve what ever issues that may have been causing a loss of power.

I do have some questions about your Meteor though. We haven't had much snow so you shouldn't of experienced any power loss. Were you loosing power or was it more a case of it just wouldn't throw snow. If it just wasn't throwing snow then you may have an impeller clearance issue. I almost never run at more than 2000ish with my blower. Being a front mount with a mid PTO I should have less HP going to it.

 

[Chilly807]

Thanks for posting this information , it is helpful looks like they added a small amount of duration on the turbo cam...

It's typical to do that to promote scavenging of the cylinders, since the intake manifold is under pressure any time the engine is loaded. Once the intake opens, air under pressure rushes in and carries spent gases out the open exhaust valve until it closes, after that the cylinder is pressurised until the intake closes.

Sean