L175 Valve adjustment

[Orange Tractors]

Hello, new Kubota owner here. I have a recently purchased L175 that sat for two or three years. I have change the fluid in the transmission with universal Hy-trans, changed engine oil Rotella (15w-40) and filter, replaced the fuel filter. I drained the old fuel from the tank and refilled with fresh offroad diesel, using Sea Foam to try to get the injectors cleaned up.

Just a couple of problems left: the valve cover leaks oil and it sounds like the valves need adjusting, but I can't find the specs for valve lash.

Thanks for any help,

Robert

[Service Dept Vic]

Hi Robert,

Valve lash on your L-175's Z750 engine is as follows:

0.007-.009 inch, engine cold, cylinder at TDC.

[Orange Tractors]

Thanks for the help Vic.

[oldtown]

is there a part number for the gasket and what is TDC?

[Bulldog]

is there a part number for the gasket and what is TDC?

I would say that TDC means Top Dead Center.

[oldtown]

great that is very immportant. did the parts number for the gasket ever come up.

[handyman]

That also means top dead center on compression stroke.handy

[oldtown]

i am doing a valve adjustment and have a few questions?

the manual provides instruction on valve adjustment, it does not differentiate or make mention of intake vs exhaust valves until you get to the part about adjusting the decompression and then it says to adjust the exhaust valve to a different clearance than the instructions for regular valve adjustment.

how are you supposed to adjust the E.V. through the peephole?

are all the valves adjusted to the same clearance?


how many marks are on the flywheel? the manual makes reference to F1 and TC

i use the alternator bolt to turn the engine but which way do i turn it?

[Orange Tractors]

i am doing a valve adjustment and have a few questions?

the manual provides instruction on valve adjustment, it does not differentiate or make mention of intake vs exhaust valves until you get to the part about adjusting the decompression and then it says to adjust the exhaust valve to a different clearance than the instructions for regular valve adjustment.

how are you supposed to adjust the E.V. through the peephole?

are all the valves adjusted to the same clearance?


how many marks are on the flywheel? the manual makes reference to F1 and TC

i use the alternator bolt to turn the engine but which way do i turn it?

Oldtown,

I didn't have a manual when I adjusted my valves. I just took the valve cover off and turned the engine over by bumping the starter until both rocker arms for one cylinder were loose; Three of my vavles were extremely loose, on the order of .016-.018". Getting them set to .009" seemed to add about twice the horsepower it had before, (by the seat of the pants dyno).I used the figures that Vic provided and didn't mess with the decrompression adjustment.

Good Luck with yours, mine makes an excellent lawnmower.

Robert

[oldtown]

thanks , i spoke to the local kubota dealer mechanic and he gave me his version. now i am confused. he recommended not to use the flywheel mark and adjust intake when exaust starts to go dwon. adjust exhaust when intake starts to come up.

i did mine with flywheel on TDC and adjusted all 4 with flywheel in that position. was that correct?

[aquaforce]

thanks , i spoke to the local kubota dealer mechanic and he gave me his version. now i am confused. he recommended not to use the flywheel mark and adjust intake when exaust starts to go dwon. adjust exhaust when intake starts to come up.

i did mine with flywheel on TDC and adjusted all 4 with flywheel in that position. was that correct?


Maybe I can be more clear as to what he is saying, he is right. No you can't adust all at TDC.

Sometimes that confusion is intentional. :( Can't blame a guy for drumming up work, but what they do is make an explanation that is confusing so a person will give up, bring the work to the mechanic and PAY!!! They need a paycheck too. :D

Anyway, the TDC and F1 thing has to do with timing the injector pump. There is F1 and F2 on the L175 since there are two cylinders. Then there is a TDC for both cylinders. How is that for confusion. :D :D


Well......................CAPTAIN CANDLE WAX will divulge this service tip that will try to simplify the valve adjust procedure. :D
It gets challenging to find material, data and engine information with most any engine as it is these days so the procedure that is used by crew chiefs and engine builders for ANY camshaft and profile is what I use. This procedure works with the natural events of the engine regardless of how many cylinders, how radical the engine or what kind of fuel it burns, internal combustion only.


Rotate the engine in its normal direction of operation and apply this procedure to one cylinder at a time. Firing order and all other parameters are irrelavant. Just do one cylinder at a time using this sequence of valve events and you can adjust any engine in the world. ;) ;)

INTAKE VALVE --- CLOSING ----- ADJUST EXHAUST VALVE
EXHAUT VALVE ---OPENING ----- ADJUST INTAKE VALVE

The opening and closing should be observed at the very begining of the valve movement (just beginning to open or just beginning to close) to indicate the stop and adjust point. Just keep turning the engine over until this specific point happens and the valve is on the heel for adjustment.

Good luck

[Orange Tractors]

Maybe I can be more clear as to what he is saying, he is right. No you can't adust all at TDC....

Rotate the engine in its normal direction of operation and apply this procedure to one cylinder at a time. Firing order and all other parameters are irrelavant. Just do one cylinder at a time using this sequence of valve events and you can adjust any engine in the world. ;) ;)

INTAKE VALVE --- CLOSING ----- ADJUST EXHAUST VALVE
EXHAUT VALVE ---OPENING ----- ADJUST INTAKE VALVE

The opening and closing should be observed at the very begining of the valve movement (just beginning to open or just beginning to close) to indicate the stop and adjust point. Just keep turning the engine over until this specific point happens and the valve is on the heel for adjustment.

Good luck

Aquaforce,

Very clear, easy to understand instructions.

This should help a lot of people to adjust valves. Now the biggest problem will be to find a feeler guage that is the correct thickness.

Robert

[traildust]

http://www.orangetractortalks.com/forums/image.php?u=247&type=sigpic&dateline=1273257283 You, my friend, are indeed one crazy son of a bitch :eek: ........ :D:D

[oldtown]

Maybe I can be more clear as to what he is saying, he is right. No you can't adust all at TDC.

Sometimes that confusion is intentional. :( Can't blame a guy for drumming up work, but what they do is make an explanation that is confusing so a person will give up, bring the work to the mechanic and PAY!!! They need a paycheck too. :D

Anyway, the TDC and F1 thing has to do with timing the injector pump. There is F1 and F2 on the L175 since there are two cylinders. Then there is a TDC for both cylinders. How is that for confusion. :D :D


Well......................CAPTAIN CANDLE WAX will divulge this service tip that will try to simplify the valve adjust procedure. :D
It gets challenging to find material, data and engine information with most any engine as it is these days so the procedure that is used by crew chiefs and engine builders for ANY camshaft and profile is what I use. This procedure works with the natural events of the engine regardless of how many cylinders, how radical the engine or what kind of fuel it burns, internal combustion only.


Rotate the engine in its normal direction of operation and apply this procedure to one cylinder at a time. Firing order and all other parameters are irrelavant. Just do one cylinder at a time using this sequence of valve events and you can adjust any engine in the world. ;) ;)

INTAKE VALVE --- CLOSING ----- ADJUST EXHAUST VALVE
EXHAUT VALVE ---OPENING ----- ADJUST INTAKE VALVE

The opening and closing should be observed at the very begining of the valve movement (just beginning to open or just beginning to close) to indicate the stop and adjust point. Just keep turning the engine over until this specific point happens and the valve is on the heel for adjustment.

Good luck


thanks for the advice, you made it alot more simple. i have got the tractor back up and running... well almost. i adjusted the valves, but i think i got the order wrong. the tractor drops 1000 rpm when i engage the mower. it also sounds different, it does not CLACK like it used to. i adjusted in this order from the front of the machine.

Intake - Exhaust - intake - exhaust,

i remember, now, from doing the valves in the mercedes that the order was

intake - exhaust - exhaust - intake.

what is the correct order ??

waiting for the engine to cool and the rain to stop.

thanks DA

[eserv]

Turn the engine either direction until one valve is just closing and the other is just opening on the cylinder you want to adjust the valves on. then turn the engine one complete turn(either direction) and then adjust the two valves for that cylinder. repeat for all the other cylinders. this way you are adjusting the valves at the top of the compression stroke just as the cylinder is starting the firing stroke. ( it is good practice to always turn an engine it's running direction)
But sometimes it's just more convenient to turn them backwards!
Ed

[oldtown]

ok i have adjusted and adjusted these valves.

the engine still bogs down easily and lacks powers.

i am going to use the TDC method that is provided in the manual.

[aquaforce]

Aquaforce,

Very clear, easy to understand instructions.

This should help a lot of people to adjust valves. Now the biggest problem will be to find a feeler guage that is the correct thickness.

Robert

Good to hear. I hope it helps others some. :)

http://www.orangetractortalks.com/forums/image.php?u=247&type=sigpic&dateline=1273257283 You, my friend, are indeed one crazy son of a bitch :eek: ........ :D:D

Sometimes I think I am crazy for getting into this kind of career. :confused: :confused: :eek: :D

[oldtown]

Turn the engine either direction until one valve is just closing and the other is just opening on the cylinder you want to adjust the valves on. then turn the engine one complete turn(either direction) and then adjust the two valves for that cylinder. repeat for all the other cylinders. this way you are adjusting the valves at the top of the compression stroke just as the cylinder is starting the firing stroke. ( it is good practice to always turn an engine it's running direction)
But sometimes it's just more convenient to turn them backwards!
Ed

when you say turn engine one complete turn, what do you mean? one complete revolution on the flywheel?

[eserv]

Yes, I mean one complete turn of the flywheel. When the valves are "rocking" ( one just closing and the other just starting to open) the piston is at Top Dead Center (TDC) Turn it one complete turn and it is again at top dead center but this time at the firing position, both valves are completely closed at that position and can be properly adjusted.
Ed

[oldtown]

Yes, I mean one complete turn of the flywheel. When the valves are "rocking" ( one just closing and the other just starting to open) the piston is at Top Dead Center (TDC) Turn it one complete turn and it is again at top dead center but this time at the firing position, both valves are completely closed at that position and can be properly adjusted.
Ed

Ok i did this and i think the valves are adjusted correctly. When the valves were rocking i made one more complete turn back to TDC on the respective cylinders, there are only two, i adjusted to.008. the machine sounds good but still lacks powers when climbing hills and when PTO is engaged.

just to give an example, when the tractor is running standing still i can adjust the throttle either by hand or with my foot and the engine is slow to respond and takes a while to come up to RPM. Before i messed with the valves the engine was very responsive.

i also bled the fuel line while running and not running thinking that air was in the line.

it may still be the valves but i wonder if something is up with the fuel delivery system.

thanks DA

[oldtown]

FYI , on TC of each cylinder i adjusted both valves at the same time. is that correct/

[oldtown]

i guess everyone is out using their tractor today instead of trying to figure out why it does not run correctly.

i have bled the lines as instructed in the article on this site. i started it up and it ran fine and then all of sudden it cut off like it was out of fuel. cranked right back up. engine was going from 800 rpm to 1500 without touching a thing then cut off again. started back up and runs fine . engine sounds great but lacks power.

IN 5th gear and PTO engaged in LO, the engine drops to 900 rpm and takes forever to gain momentum. if i am on a hill it wont go and has to be saved from dieing by depressing the clutch.

[eserv]

I don't believe your problem is valve adjustment. If the valves were enough out of adjustment to effect power so drastically you would have extreme difficulty getting the engine started.

[oldtown]

what in the world is going on. tractor starts good. it ran fine before i "Fixed IT"

[eserv]

Maybe you are like my ex-fatherinlaw, He fixed lots of things until they were broke! Seriously though, does the tractor idle smooth? Does it smoke under load? Is there some other parasitic load? ( three point hitch adjusted to high, loader hoses not properly attached etc?)

[oldtown]

it does idle smooth. it does not smoke under load. a little smoke when i start but that is it. but it wont take a load either. throttle is slow to respond and once again when i activate the PTO it cant handle it and the RPMs drop off.

not sure if it makes a difference but i did replace the fuel filter with one from auto zone the numbers were cross referenced. it fit and is the same size as the original.

i have adjusted the valves using the TDC method that you recommended, when the valves were rocking at TDC, i spun it around another complete turn to TDC and adjusted.

i also used the method that aquaforce recommended. which the first part is at TDC but the second part is not.
INTAKE VALVE --- CLOSING ----- ADJUST EXHAUST VALVE
EXHAUT VALVE ---OPENING ----- ADJUST INTAKE VALVE

using both methods tractor ran about the same, seems like the aquaforce method had a LITTLE more power, ran louder, the reaction time of the throttle seems better.

one more thing i noticed when i had them adjusted on the TDC method. i noticed that you could hear the pull on the engine when i turned the key on and off. it was slight but you could hear it. it seems like hitting the key for the charging system would not have any affect. The TDC method sounded smoother.

when i bled the fuel system, with the engine running, i loosened #1 at hte injector and of course fuel went everywhere, the engine stayed alive and did not falter. however as soon as i broke the seal on #2 cylinder at the injector
the motor quit.

that is all the details i have.

[eserv]

Sounds like one or more of your delivery valve holders are loose. Try loosening the injector lines at the pump and tightening the fitting just below the injector line nuts. this is the delivery valve holder and can cause similar problems to what you have if they are loose. it is easy to loosen them by mistake when you are removing the injector lines. Kubota have a locking device on them but it isn't strong enough if you have stubborn fittings. Just tighten them down firmly and reinstall the lines.
Ed

[Orange Tractors]

it does idle smooth. it does not smoke under load. a little smoke when i start but that is it. but it wont take a load either. throttle is slow to respond and once again when i activate the PTO it cant handle it and the RPMs drop off.

not sure if it makes a difference but i did replace the fuel filter with one from auto zone the numbers were cross referenced. it fit and is the same size as the original.

i have adjusted the valves using the TDC method that you recommended, when the valves were rocking at TDC, i spun it around another complete turn to TDC and adjusted.

i also used the method that aquaforce recommended. which the first part is at TDC but the second part is not.
INTAKE VALVE --- CLOSING ----- ADJUST EXHAUST VALVE
EXHAUT VALVE ---OPENING ----- ADJUST INTAKE VALVE

using both methods tractor ran about the same, seems like the aquaforce method had a LITTLE more power, ran louder, the reaction time of the throttle seems better.

one more thing i noticed when i had them adjusted on the TDC method. i noticed that you could hear the pull on the engine when i turned the key on and off. it was slight but you could hear it. it seems like hitting the key for the charging system would not have any affect. The TDC method sounded smoother.

when i bled the fuel system, with the engine running, i loosened #1 at hte injector and of course fuel went everywhere, the engine stayed alive and did not falter. however as soon as i broke the seal on #2 cylinder at the injector
the motor quit.

that is all the details i have.

It sounds to me like you have the vavles adjusted okay; at least for now, but you have further problems. It is natural to feel that you have screwed up the last thing you worked on, and to suspect that.

I'm not really a diesel mechanic, but the last paragraph tells me you aren't getting any fuel to the #1 cylinder, and are only running on #2. You are getting fuel to the #1 injector; but it is not getting into the cylinder. I would either get that injector tested and repaired, or replace it; they aren't that expensive.

Robert

[oldtown]

well i tried the old take it apart and put it back together. also i left the fuel line on the #1 cylinder that was apparently blocked and took the line off the #2 cylinder which was not and she started right up. so we are now operating on all cylinders!! yeah. must have been a little bit of trash.

now for one last question.

which valve adjustment do i use? the TDC method or the aquaforce method. ?

thanks for all the trouble shooting help. i will post pics asap.. now i can move on to redoing the decals.

[Orange Tractors]

Oldtown,

Either method will work, as long as you understand what you are trying to accomplish. When you adjust valve lash on an engine with mechanical lifters; what you are doing is setting the amount of clearance, or slack, that is built into the system. If the rocker arm is too tight, when the engine heats up do to combustion temperatures the valves will not fully close, causing loss of compression, lack of power, and maybe burning valves and seats. If the rockerarm is too loose, on the intake you won't get enough air to allow the fuel that is injected to fully combust; if the exhaust valve is too loose you will not get all the burned fuel out of the cylinder, also causing incomplete combustion, because there is not enough oxygen available to burn the next charge of fuel.

As Vic stated in his reply to my first post on this subjectl valve lash, (or clearance) is .007" to .009" with the engine cold.

Here is how I adjusted my valves.

After taking the valve cover off, I turned the engine over a couple of times just to be sure everything was moving like it should.

Then I bumped the starter until both rocker arms on the front cylinder were loose, indicating that the piston was at top dead center of the compression stroke.

I then measured the clearance between the rocker arm and the valve stem. (All of my valves were too loose, one was at about .011" the othe three were around .016"-.018").

Loosen the lock nut on the adjuster, then turn it in until it lightly touches your feeler guage.

Tighten the lock nut and do the other valve on that cylinder. Very important that this gets tightened.

Repeat the operation for the other cylinder, then put the valve cover back on.

After replacing the valve cover I adjusted the decompression linkage, to make sure that it didn't affect anything. (the knob on mine is broken off, I didn't replace it. I only use this tractor for lawn mowing.)

That is basically it. Like I said; by adjusting the valves on mine, it seemedlike I had twice the available horsepower and torque.

I know that it is frustrating to work on a piece of equipment, and not have it come out right the first time. Perseverance and attention to detail will obtain the desired results.

Good luck,

Robert

[meanjean]

Can someone speak to this last question?

[eserv]

Kinda OK except just because the rockers are loose doesn't mean the cam is in the ideal position to be adjusted.

[aquaforce]

Can someone speak to this last question?



I hope you saw my post on page two of this thread.

Are you talking about the TDC reference in that last question? TDC is only a reference point if the camshaft heel and toe profile are going to be followed for specific adjustment points in the firing order. Following the procedure I listed ONLY follows the heel and toe of the cam and the adjustment procedure can be done on any cylinder in any order.