96 Geo Metro Lsi with tapping rockers

[AsylumEscapee]

ok I have a recurring problem.
In my 96 Geo Metro LSI my 4 cyl 1.3L (90k miles) has had worn out rocker arms twice now. I pulled a set from a junk yard (from a seemingly newly rebuild wreck) and replaced the cam as well last summer. This summer the problem has repeated itself.

Here's what's happening:

The rockers have hydrolic lifters in them. Oil is injected through the rocker arm to close valve clearance as the arm tilts. This occurs through a small hole in the rocker mount which is hollow, and has to line up perfectly with a small hole in the rocker arm. What has happened is the header mount that holds the rocker assembly is eating away at the side of the rocker arm causing it to slowly shift to the side until the holes no longer line up. This causes tapping because the lifters fail to work without oil. It can also lead to one or more of the hydrolic lifters to get stuck in the extended position, or even eject it completely, causing the rocker to eat away at the cam lobe.
I am still trying to determine a permanent fix other than a replacement head. Given the way the springs press the rocker against the mount, the problem would occur in any head unless some kind of half round cap was installed over the rocker assembly at these places, to complete the surface that rubs against the rocker, rather than a knife like edge...
Its going to take me some time to measure clearance and find appropriate washers to somehow fix in place (so they don't eat away and then break into pieces causing even more damage...)
Some of the mounts have actually worn slightly where the rocker rubbed.

You should be able to check for this damage easily by pulling the valve cover. It's quick and easy, takes a number 10 socket.

I found it to be consistent in 5 other metros I found in the junk yard.
All of them had the same wear. Many of them had replacement cam assemblies, but showed signs of wear on header mounts. Apparently it is a major problem causing significant damage.

Now from my experience, hydrolic lifters are very expensive from dealers or auto stores. You can't easily trust lifters from the junk yard. Personally I don't know how to service them. I found a site online, called parts dinosaur.com I think. They sold the lifters at 8 for 20 dollars! great find.
Now these little buggers just pull out and push into the groved hole in the rocker. Use pliers and only grip the sides of the tip. They are very sensitive to dirt because of their tiny groves and holes that oil must pass through.
they have tiny o rings on them.
{When they retract the oil in them squirts out of the side of the rocker (to lube the cam)}


So If you have tapping , pull the valve cover and look for rocker arm damage, for lifter extrusion, and for cam lobe wear. Also look for damage to the mounting posts.
If you let this go, the rocker will break completely, and you will lose one or more cylinders (causing engine lag, loss of power, excessive gas consumption, and very rocky idle...)

Although another cause of tapping I also have is my intake rocker on cylinder 1 is actually hitting the valve cover... (must be warped...)


I would love to hear anyone's experience on this matter , and any useful advice would be greatly appreciated.