fd620d pushrod falls out of rocker on one valve

[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?

 

[StarTech]

Possible loose valve seat.

 

[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

 

[slomo]

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

slomo

 

[cpurvis]

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

 

[Willibe]

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

The pushrod falls out of the rocker cup through a full rotation of the camshaft, and only this one pushrod.

 

[Willibe]

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

The valve guide is fully seated. The compressed spring measures the same as the other 3 springs.

 

[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

 

[cpurvis]

The pushrod falls out of the rocker cup through a full rotation of the camshaft, and only this one pushrod.

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.

 

[Joed756]

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