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fd620d pushrod falls out of rocker on one valve

#1

W

Willibe

I had the cam shaft (plastic gear) and valves replaced by a JD dealer after an engine failure. Was told then there was oil blow-by, but they didn't repair bottom end engine at their facility and I would need to take it elsewhere.
I finally got tired of the oil usage and carboned spark plug, so I pulled the engine and tore it down to replace the rings. I bought a kit with gaskets, seals, pistons and rings...no valves, springs or pushrods.
I didn't pay attention to the pushrods when I pulled the head.

The issue: With the engine at (TDC) top dead center, I Installed the exhaust valve pushrod on #2 cylinder head, after seating the pushrod in the the lifter, it falls out of the of the rocker. If I turn the crank 180 degrees it will stay in, but with a full turn it falls out again.

Checks/ balances: With all things being equal, I switched pushrods, rockers, springs, camshaft with the same results. I checked the head for flatness, measured the springs for free length, There is not enough thread on the rocker screw to adjust. The pushrod appears to be approximately 1/8 to 1/4" short of seating into the rocker.

Has anyone seen anything like this or have some opinions?


#2

StarTech

StarTech

Possible loose valve seat.


#3

R

Rivets

Check to see it the valve guide has moved up, not allowing you to adjust the valve clearance. Here is a service manual that may be of some help. https://www.mymowerparts.com/pdf/Ka...20D-FD661D-KAWASAKI-SERVICE-REPAIR-MANUAL.pdf


#4

S

slomo

Possible dirty cylinder cooling fins overheating the block chunking push rods. Taryl shows a moved valve guide eating pushrods.

slomo


#5

cpurvis

cpurvis

Is the rocker arm stud pulling out of the head when you rotate the engine?


#6

W

Willibe

cpurvis said:
Is the rocker arm stud pulling out of the head when you rotate the engine?
Click to expand...
The pushrod falls out of the rocker cup through a full rotation of the camshaft, and only this one pushrod.


#7

W

Willibe

Rivets said:
Check to see it the valve guide has moved up, not allowing you to adjust the valve clearance. Here is a service manual that may be of some help. https://www.mymowerparts.com/pdf/Ka...20D-FD661D-KAWASAKI-SERVICE-REPAIR-MANUAL.pdf
Click to expand...
The valve guide is fully seated. The compressed spring measures the same as the other 3 springs.


#8

S

slomo

Take a picture of everything you are seeing. Will help a lot. Lot of times we hear someone has cleaned or replaced everything and it still doesn't run, like your post. Show us what you are doing.

I want to see a picture of the cylinder cooling fins and valve guides.

slomo


#9

cpurvis

cpurvis

Willibe said:
The pushrod falls out of the rocker cup through a full rotation of the camshaft, and only this one pushrod.
Click to expand...
That's why I asked if the rocker arm stud is pulling out of the head. If you can rotate the engine two full turns and the lash on that one rocker arm goes from 'correct' to completely loose, either:

The rocker arm stud is pulling out of the head;

Valve is not returning to a closed condition;

OR the lifter is collapsing, IF it has hydraulic lifters.


#10

J

Joed756

Is your push-rod bent? Roll it on a sheet of glass to find out.


#11

W

Willibe

Joed756 said:
Is your push-rod bent? Roll it on a sheet of glass to find out.
Click to expand...
I not only rolled it on a flat surface, but used a straight edge as well. I also switched it with the other existing pushrods. Everything checks true.


#12

W

Willibe

slomo said:
Take a picture of everything you are seeing. Will help a lot. Lot of times we hear someone has cleaned or replaced everything and it still doesn't run, like your post. Show us what you are doing.

I want to see a picture of the cylinder cooling fins and valve guides.

slomo
Click to expand...


#13

W

Willibe

Slomo, here are the pics.

Attachments















#14

S

slomo

Willibe said:
I not only rolled it on a flat surface, but used a straight edge as well. I also switched it with the other existing pushrods. Everything checks true.
Click to expand...
You can't roll this kind of push rod. There are balls on the ends.

slomo


#15

S

slomo

Willibe said:
Slomo, here are the pics.
Click to expand...
From what I can see, the adjustment stud "looks" like it is worn down to a chisel point??? Pic has a light bounce glare and is blurry at the spot in concern. Is the adjustment stud the same size and shape exactly as the adjacent one? On top of the jam nut, both adjustment stud lengths "look" the same. What do you have below?

slomo


#16

R

Rivets

I’ve reread this thread and have a couple of stupid questions. Do you have the part numbers for both the replacement valves and cam? Do you have the old valves? Reason I ask is that something doesn’t look right in the pics. On the loose valve the keeper looks like it is sitting almost flush with the end of the valve stem, while the other looks about 1/16” above. I’m wondering if you have the correct cam and valves installed. Also include your engine serial numbers please.


#17

Hammermechanicman

Hammermechanicman

The height of the IN and EX valve stems should be within a couple thou of each other with valves seated.. take the rockers off and put a rule across the end of the valve stems. It should be level with the head. If not you have a valve problem. Springs, retainers and keepers should look the same on both valves when both are seated. Tappets, pushrods and rockers are all the same so you can swap them around. I am going to assume you have the engine sump cover on when checking valve lash.


#18

StarTech

StarTech

Can even be a loose valve seat though I have yet to one on a Kawasaki engine; but always possible.


#19

S

slomo

Also on that loose valve, the oil seal looks deeper in the head. Valve guide moved down in the picture? Sticking valve guide not allowing said valve to close all the way up? Valve seat out of pocket like StarTech said?

slomo


#20

S

slomo

Not much of a JD dealer if they can't put piston rings on.

Swap valves and see what you have. Measure both and see what you have. Like Rivets said, incorrect valves?

slomo


#21

StarTech

StarTech

slomo said:
Not much of a JD dealer if they can't put piston rings on.

Swap valves and see what you have. Measure both and see what you have. Like Rivets said, incorrect valves?

slomo
Click to expand...
Hey the local dealer couldn't find a bad spark on Stihl Hedger or a loose fuel solenoid connector on a Z925A. So would you expect them to be able do anything that requires more brains?

On of my customer brought a brand new Z950M and will not let them even touch it repair wise.


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