How do I set the rocker arm assembly?

[Lzybmbjj30]

I set the flywheel where the 1TC mark is aligned with the notch. From this point I don't really know what to do. I don't know which piston is piston#1. There are like 6 of these rocker arms. One side of the arm sits on a springs and the other on rods. The rocker arm assembly, when I put it on, doesn't sit completely flush because the rods are somewhat uneven. I'm assuming once I set the flywheel to the proper position that the rods are all supposed to be even and that the assembly should sit flush.

Is it just saying to set the flywheel 1TC mark to the notch and then to simply adjust the screws until every rocker arm is at 0.0057 t o 0.0073 in or is that just for the first piston?


-These are the copied and pasted instructions. I understand down to step 4 but can someone maybe explain the rest in English to me?-

1. Remove the head cover.
2. Align the "ITC" mark on the flywheel and punch
mark (1) on the plate so that the No. 1 piston comes to the compression or overlap top ded dead center.
3. Check the following valve clearance marked with ''0''using a feeler gauge.
4. If the clearance is not within the factory specifications, adjust with the adjusting screw.
I Valve clearance
NOTE
0 The "TC" making on the flywheel is just for No. 1
cylinder. There IS no "TC' marking for the other
I Factory I 0.145to0.185 mm spec. 0.0057 t o 0.0073 in.
I
cylinders.
0 No.1pistoncomes.totheT.D.C. ositionwhenthe
0158F016
(2) TCMark Line
(3) Valve Clearance
0
0 0
"TC" marking is aligned with tRe punch mark of the rear end plate. Turn the flywheel 0.26 rad. (15') clockwiseandcounter-clockwisetoseeifthe piston is at the compression top dead center or the overlap position. Now referring to the table below, readjust the valve clearance. (The piston is at the top dead center when both the In. and EX
when both the valves move.
Finally turn the flywheel 6.28 rad. (360') to make sure the "TC" marking and the punch mark are perfectly aligned. Adjust all the other valve clearances as required.
After turning the flywheel counterclockwise twice or three times, recheck the valve clearance.
After adjusting the valve clearance, firmly tighten the lock nut of the adjusting screw.
ve arrengemen
Iscompresslontop

 

[jcy110]

That is usually for the #1 Piston, then you crank the flywheel around until piston #2 is ready to check with the feeler gauges and so on. If you tighten them all down when #1 is top dead center you will bend or break everything on the other cylinders......There is usually a gap setting for the intake and exhaust valve when the flywheel is turned to a specific point, that is what you need to find out.

 

[Tooljunkie]

The manual wants you to set valves at top of compression stroke. Not familiar with engine. So #1 is easy. If you watch valves open/close you will be able to feel next cylinder reach top of stroke. Its the stroke after intake valve cycles. Really if you check for clearance right after intake valve opens/closes you will be vey close and should find there is a small gap between rockers and valves.

 

[North Idaho Wolfman]

The push rods will be uneven because they are all at different places on the cam, you need to bolt the rocker arm assembly down completely before you even start any adjustments.
FYI, you probably don't even need to adjust the adjusting screws as they were already set right before you took it apart.

Once everything is bolted down, then you can do as Tool junkie said turn the motor the right direction and watch the valves when the intake closes check the valve lash on just that cylinder, then move to the next and do the same, and then the last, easy and done.

Use a .007 feeler gauge to set the valves.
Note, #1 is always the cylinder that is closest to the gear case / water pump on a Kubota, never go by "it's the front of the tractor, because like in this case the engine is mounted backwards in the tractor!

 

[Lzybmbjj30]

That's the other thing. The rocker arms are the same as when I removed them so is it possible that I don't need to mess with them?

 

[North Idaho Wolfman]

That's the other thing. The rocker arms are the same as when I removed them so is it possible that I don't need to mess with them?

Yes that is most likely the case!

 

[Kubota Newbie]

Uhhhhh, Nope! If you removed the rocker assembly the valves must be re-set. Would they be "close enough" to bolt it on to get started with the adjustment procedure? Maybe, but you should really loosen the locking nuts, back the adjuster screws out 2-3 turns, install the rocker shaft assembly and then proceed as directed in the service manual. Make sure as you bolt the assembly on that the pushrods are seated correctly on the lifters AND on the ball of the adjuster screw.
You didn't say why you took it off to begin with. Was the head serviced? Milled? New head gasket? Valves serviced/ground? All of these things will result in a change in the clearance compared to disassembly. Even just re-tightening the head bolts to spec can cause a change.
Failing to adjust the valves correctly will result in 1). not running at all, 2). running poorly, or 3). damage to valves/valve train and perhaps pistons. Just not worth taking the chance. Sorry

 

[lugbolt]

Screw Kubota's way of adjusting valves. It's the hard way. I have always used the EOIC method. Exh opening intake closing (that's what EOIC stands for).

Choose a cylinder. #1 for example. Turn the engine over in it's normal direction of rotation until the exhaust valve JUST starts to open. Stop. Adjust intake valve. Once the Intake's set, turn the engine until the intake valve is ALMOST closed (but not all the way). Check/adjust clearance on the exhaust valve. This method is almost foolproof if done correctly. Repeat the same process for the other cylinders.

When removing the shaft assembly (or installing it) it makes no difference where you put the flywheel. If you have it on #1 TDC, then some of the other valves are going to try to open as you tighten the shaft assembly. Best bet is to drop the shaft assembly on, any stroke, then install the pushrods. Most of the Kubota 2 valve engines you can just push the valve spring down with your fingers anyway. 4 valve is a different story but it's still not rocket science.

 

[Lzybmbjj30]

How do I know what valves correspond to cylinder 1? How do I know which one is the intake valve and the exhaust valve for cylinder one? How do I know that the exhaust valve is starting to open?

 

[D2Cat]

Lzybmbjj30, your best bet would be to go to YouTube and find someone SHOWING you how to adjust the valves. Seeing the process will maybe clarify your situation.

To determine what is an intake or an exhaust valve, look at the position of the valve in the head. The intake will lined up with its position on the intake manifold and the exhaust will be to the exhaust manifold.

Go back over Lugbolt's second paragraph, try to get a picture of what he's explaining. Then go look for a YouTube video of someone doing the adjustments. Then you'll have an "A-hah" moment!

 

[Lzybmbjj30]

Are you referring to where the rods line up with the 3 intake holes and then the other 3 on the other side for the exhaust?

 

[Kubota Newbie]

So I'm a great proponent of doing things yourself... But it seems pretty clear from your posts that this is your first adventure into reassembly of any kind of overhead valve 4 cycle engine. Perhaps the best approach would be to have someone over that has a little experience with this sort of thing, not to do it for you of course, but to kind of coach you through it a little so you have a better understanding of which parts are doing what and why they are adjusted in a particular manner.
lugbolt is right, it's not rocket science, BUT if you've NEVER done it before then advice from someone who has in a post on a forum can seem nonsensical. There are tons of little details someone looking over your shoulder could point out the first time through. Next time you'll have a better understanding of why it works the way it does.

 

[Lzybmbjj30]

I think I understand the eoic method now. So on cylinder one on theach intake valve I rotate the crank until that one just starts to rise. That's when I adjust it to specifications. I then go to the exhaust and turn the crank just to the point where it starts to fall. I adjust it and do the same with all 6 of them. Is this pretty much correct?

 

[Lzybmbjj30]

Actually reverse what I said. I meant exhaust starts to rise intake starts to lower. One issue. There's a nut and a notch for a screwdriver on the opposite side. I'might trying to loosen the nut counter clockwise. How hard is that nut supposed to be to turn? Am I only supposed to loosen the when then cylinders are TDC?

 

[D2Cat]

Kubota Newbie has given you sound advise.

When the spring you are seeing on the top of the engine head is at it's fullest height....that's when the valve is closed. The spring is what is forcing the valve up against the head.

You get all the valves to that position and adjust to .008 the engine will run.

But I want to know how you are going to loosen the nut, turn the adjustment screw, install the feeler gauge, move the gauge to confirm it's not too tight or too loose, and tighten the nut while holding the adjustment screw, without changing anything....

Once again, humble yourself to find a good coach.

Some great philosopher said:

I hear and I forget,
I see and I remember.
I do and I understand.

 

[Tooljunkie]

Its basically a matter of timing, engine turning, valves opening and closing in a pre-determined order. In order for valves to seal when engine is hot, there needs some room for expansion and contracting when it cools. Hence the setting for clearance between rocker and valve stem tip. for illustration purposes. When tappet(thing that runs against cam to push on rod)reaches the point that is highest from cam,valve is fully opened.
At point where valve should be set is at lowest part of cam. One or both valves can be set depending what stroke is starting at top dead centre. Cam rotates once for every two rotations of crankshaft.

Hopefully i havent confused you any more.
We didnt all know everything from the start,for some it comes easier than others. Knowledge is a gift to share. Wolfman is a perfect example of this.

 

[Lzybmbjj30]

Okay so I think I did it right last night. When the flywheel is on the TDC notch valves 1,2,4, and 5 are at their highest and there is a little bit of play between the arm and the spring. That when I adjusted those valves. I then rotated the flywheel 360 degrees until valves 3 and six where right at the top just before they go down. I thin did the same thing. I adjusted the space and tightened the nut and checked it again so that there is just a slight drag with the .006 feeler. I then rotated it a few times and checked the distance again through each cycle. I guess you have to rotate the flywheel twice to get it to go through the cycles. The first rotation 1,2,4,5 are at their peak and the 2nd cycle 3 and 6 are at their peak.

 

[North Idaho Wolfman]

This thread is becoming the perfect example how NOT to set your valves.

Several have tried to explain to you in great detail how to properly set the valves and you still ignore their advice.

I think it's getting about to the point to "abandon all hope".

 

[Lzybmbjj30]

The manual wants you to set valves at top of compression stroke. Not familiar with engine. So #1 is easy. If you watch valves open/close you will be able to feel next cylinder reach top of stroke. Its the stroke after intake valve cycles. Really if you check for clearance right after intake valve opens/closes you will be vey close and should find there is a small gap between rockers and valves.


Tool junkie posted this in the second response. I don't think what I explained was ignoring his advice.