4A-GE valve shim disintegrated

[DaLanZhu]

On my 86 a valve shim on the intake valves disintegrated. The shim broke into 5 pieces, luckily I was able to find all of them.
The lifter is damaged, and stuck in the cylinder head. The valve is stuck open.








Initially I was thinking about replacing the cylinder head entirely, but looking at the damage I think what might work is to grind off the damaged aluminum in the cylinder head using a Proxxon tool, polish it and install with new camshaft, lifter and shim.
What are your thoughts on this? I am not super familiar with all these grinding sockets for the Proxxon, any tool recommendation to minimize further damage?

[Dave W]

If it was my head, I would try to save it. I think after removing the head, I would try to push the lifter a little lower to help in removing the burrs and prevent any more damage to the surface, before grinding on the head. I would use a medium grit stone in a Dremel tool to cut back the aluminum. Fill the lifter bore with a small layer of grease to prevent the grinding dust getting further down, inside the ID. Getting the lifter out is going to be a real PITA. You might be able to use trans ring pliers to remove the lifter, but I would guess that you will probably have to get a nut welded on to the top of the lifter and then used a slide hammer to remove. Carefully polish the lifter bore with 600 wet and dry paper, then clean the complete head several times. I would also use the 600 paper on the camshaft lobe and lightly polish the surface.
Depending on your milage, you might want to consider getting a valve job, since you are already doing 90% of the work.

[DaLanZhu]

Thanks! Good news is that I was able to grind open the lifter and remove it. Since the valve still remained stuck open I had to remove the head, and finally managed to remove the valve.
The problem was that the valve stem and guide were full of oil sludge, causing the valve to jam and remain stuck open. I had to use a hammer and pin to get the valve out.
The valve even hit the piston, there are clear print marks.
Luckily, the valve guide still looks good. I will now replace valve, lifter, shim, camshaft and reassemble it. I will also remove all other valves and clean the valve guides.