Johnbro
Gold Member
If the IP timing was retarded, wouldn't there be other problems other than a few seconds of lumpy idle/white smoke at cold start? Things like over heating, excess black smoke, poor fuel economy?
L5740 Cold Start
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If the IP timing was retarded, wouldn't there be other problems other than a few seconds of lumpy idle/white smoke at cold start? Things like over heating, excess black smoke, poor fuel economy?
leonz
Super Member
Yes but the timing has been advanced on the smaller tractors coming off the assembly floor to reduce the exhaust emmisions and diesel particulates to get under the EPA's current rules and regulations.
The issue is vibration at "Low Idle Speed" and the amount energy created because of the advanced injection pump timing which quite ofte becomes much more pronounced when the engine speed is increased and becomes unbearable.
Its a simple fix after the sale and it can be done quickly to make the problem GO AWAY FOREVER.
The issue is vibration at "Low Idle Speed" and the amount energy created because of the advanced injection pump timing which quite ofte becomes much more pronounced when the engine speed is increased and becomes unbearable.
Its a simple fix after the sale and it can be done quickly to make the problem GO AWAY FOREVER.
leonz
Super Member
Anything above the L series has the
pollution controls in it as far as i know
and the smaller ones have
"the Voodoo adjustments"
as they are strictly sized via the C.C. or Cu In.
displacement per the EPA guide lines which
I added here a few weeks ago.
All they need is a catalytic muffler
"Diesel Exhaust Gas Purifier" and this
business would end and they would
sell more of them and have customers
for life.
The Exhaust Gas Purifiers are easy to add
to any diesel and as long as the motor is
in good condition and the tractor is held
at high R.P.M. while working.
The engines high temperature exhaust gas
emmisions are converted to Carbon Dioxide
and water vapor.
pollution controls in it as far as i know
and the smaller ones have
"the Voodoo adjustments"
as they are strictly sized via the C.C. or Cu In.
displacement per the EPA guide lines which
I added here a few weeks ago.
All they need is a catalytic muffler
"Diesel Exhaust Gas Purifier" and this
business would end and they would
sell more of them and have customers
for life.
The Exhaust Gas Purifiers are easy to add
to any diesel and as long as the motor is
in good condition and the tractor is held
at high R.P.M. while working.
The engines high temperature exhaust gas
emmisions are converted to Carbon Dioxide
and water vapor.
DDT
Platinum Member
- Joined
- Dec 18, 2000
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- Clay Center, Kansas
- Tractor
- Kubota M6040/cab, BX25D, RTVX900
I talked with service man to day, He said the tier 1 and 2- 40 series timming specs were 16.5 to 17.5* the teir 3 engines timming specs are 8.5 to 10*. he also told me the tier 3 s had a smaller cam lobe to help emisions.
crazyal
Super Member
I don't know about any other GL40 owners but my 4240 is very smooth. From idle all the way up to top RPMs. Sure when it's first started when cold out it's a bit rough and smokes some but so are the other two diesels I own. After a few seconds it clears up and runs fine. I don't think I own an engine that doesn't run a little rough when first started in 0 degree weather.
bitseeker
Silver Member
I agree. Our GL5240 puts out a little smoke and runs raggedy for a few seconds when first started in cold conditions. It always starts in just a few cranks. It then smooths out and idles like silk. Subsequent starts when warm are smoke and vibration free. Our BX23 acted the same way.
Isn't incomplete combustion (causing the smoke and roughness) normal for diesel combustion because there is no spark, and reliable ignition and complete burn depends on heat and compression which improve when the combustion chambers warm up?
leonz
Super Member
Any diesel in good condition no matter the size will have a single puff of black smoke when the combustion cycle starts and then barely any smoke at low idle unless the air filters are plugged.
If you have an extended period of black smoke like the OP and the chugging where you can hear each cylinder complete its combustion cycle with a huge amount of effort and then the following cylinder repeat i would have them examine the timing to be sure its at Zero T.D.C.
If you have ever been next to a railroad locomotive when it is idling its smooth and balanced and you cannot hear each cylinder complete its combution cycle like you would with a diesel with advanced timing.
the above is what you want with your tractor.
If you have an extended period of black smoke like the OP and the chugging where you can hear each cylinder complete its combustion cycle with a huge amount of effort and then the following cylinder repeat i would have them examine the timing to be sure its at Zero T.D.C.
If you have ever been next to a railroad locomotive when it is idling its smooth and balanced and you cannot hear each cylinder complete its combution cycle like you would with a diesel with advanced timing.
the above is what you want with your tractor.
bitseeker
Silver Member
Thanks Leonz,
My tractors have more than a single puff, yet there is no smoke or vibration at low idle after a few seconds.
Above, the specs for a couple of classes of diesel injection timing were quoted:
- Tier 1 & 2- 40 series ... 16.5 to 17.5 BTDC
- Tier 3 ......................... 8.5 to 10.0 BTDC
Are those specs incorrect?
Should all be reset to Zero T.D.C.?
Chilly807
Elite Member
Interesting thread... I can honestly say I've never , ever, in over 25 years of diesel repair and fuel injection work seen a diesel set at 0 degrees BTDC for start of fuel delivery. Most are between 15 and 35 degrees BTDC depending on the combustion chamber design and compression ratio.
I have attached a picture of the engine label on my 3400, which works perfectly normal in cold weather in my opinion. Notice the injection timing is 17.25 degrees BTDC.
We've recently done some diesel engine testing through work involving attaching a pressure sensor to the fuel injection line and another one attached to the cylinder head to measure the pressure rise in both areas vs. degrees of crank rotation on a running, loaded engine. There is also a sensor in the injector tip to measure when the needle lifts and injection actually begins. With timing set at 32 degrees BTDC, the actual ignition point is approximately 6 to 9 degrees after TDC on the power stroke. Diesels have a phenomonon called ignition lag, measured in degrees of crank rotation from the time fuel is injected into the combustion chamber until it begins to burn. This is a normal facet of diesel operation, and is why fuel must be injected well before TDC.
That's a V16 turbo intercooled engine turning at 1800 rpm and making well in excess of 1000 HP at full power. We had reliability issues that led to a study of what was happening with combustion pressures and fuel timing.
After experimenting with different injection timing, it was discovered that retarding the timing even 5 degrees resulted in excessively high exhaust gas temperatures, poor combustion, and reduced power for an equivalent amount of fuel consumed. Advancing the timing beyond the original design resulted in extremely high cylinder pressures, cracked and broken connecting rods, etc.
That's 5 degrees or less of change, and here we're discussing retarding it over 15 degrees?? Come on people, have some faith in Kubota and the other manufacturers. They DO know what they're doing, it's one of the reasons they're one of the leaders in small diesels worldwide.
Changing timing affects primarily cylinder pressures, but does have a secondary effect on exhaust gas temperature. Changing the amount of fuel delivered affects primarily the exhaust temperature, with a slight change in cylinder pressure. The two variables are quite different and both are independently adjustable on all diesels I'm aware of.
There's a lot more to adjusting fuel timing than most folks realize. You're changing a design parameter that's been carefully set to provide a balance of the best performance and engine life, while still meeting emission standards.
As some have tried to point out, diesels don't work particularly well when they first start in frigid conditions. Cylinder temps barely support combustion, so yes they will run rough and exhibit grey-white smoke until the cylinders warm up. There's normally a puff of heavy black or grey smoke on start-up, then it will reduce to a lesser level and eventually go away entirely as the engine warms up. The governor will keep adding fuel to maintain idle.
Suggesting that the timing should be set to 0 degrees BTDC regardless of what Kubota has designed it to be, makes absolutely no sense to me. I seriously doubt any dealer will warranty an engine that has had that done, I certainly wouldn't.
And that, my friends, is my opinion.
Sean
I have attached a picture of the engine label on my 3400, which works perfectly normal in cold weather in my opinion. Notice the injection timing is 17.25 degrees BTDC.
We've recently done some diesel engine testing through work involving attaching a pressure sensor to the fuel injection line and another one attached to the cylinder head to measure the pressure rise in both areas vs. degrees of crank rotation on a running, loaded engine. There is also a sensor in the injector tip to measure when the needle lifts and injection actually begins. With timing set at 32 degrees BTDC, the actual ignition point is approximately 6 to 9 degrees after TDC on the power stroke. Diesels have a phenomonon called ignition lag, measured in degrees of crank rotation from the time fuel is injected into the combustion chamber until it begins to burn. This is a normal facet of diesel operation, and is why fuel must be injected well before TDC.
That's a V16 turbo intercooled engine turning at 1800 rpm and making well in excess of 1000 HP at full power. We had reliability issues that led to a study of what was happening with combustion pressures and fuel timing.
After experimenting with different injection timing, it was discovered that retarding the timing even 5 degrees resulted in excessively high exhaust gas temperatures, poor combustion, and reduced power for an equivalent amount of fuel consumed. Advancing the timing beyond the original design resulted in extremely high cylinder pressures, cracked and broken connecting rods, etc.
That's 5 degrees or less of change, and here we're discussing retarding it over 15 degrees?? Come on people, have some faith in Kubota and the other manufacturers. They DO know what they're doing, it's one of the reasons they're one of the leaders in small diesels worldwide.
Changing timing affects primarily cylinder pressures, but does have a secondary effect on exhaust gas temperature. Changing the amount of fuel delivered affects primarily the exhaust temperature, with a slight change in cylinder pressure. The two variables are quite different and both are independently adjustable on all diesels I'm aware of.
There's a lot more to adjusting fuel timing than most folks realize. You're changing a design parameter that's been carefully set to provide a balance of the best performance and engine life, while still meeting emission standards.
As some have tried to point out, diesels don't work particularly well when they first start in frigid conditions. Cylinder temps barely support combustion, so yes they will run rough and exhibit grey-white smoke until the cylinders warm up. There's normally a puff of heavy black or grey smoke on start-up, then it will reduce to a lesser level and eventually go away entirely as the engine warms up. The governor will keep adding fuel to maintain idle.
Suggesting that the timing should be set to 0 degrees BTDC regardless of what Kubota has designed it to be, makes absolutely no sense to me. I seriously doubt any dealer will warranty an engine that has had that done, I certainly wouldn't.
And that, my friends, is my opinion.
Sean
