Lifters or Cam?

[Cozmopaws]

I posted this in the Tech area but no response. Any help appreciated.

"Geo Metro 1.3 ohc. Knocking seems to be getting more and more pronounced. Told it may be lifter(s) that is out of adjusment or needs replaced.

Anyone had experience with this or any other vehicle? Am thinking it could be a timing issue as well (maybe 1/2 teeth off) but if that's the case, it is slipping more and more.

Am also told the lifters have carbon points which means they wear slower than the cam which means it could be a worn cam shaft?

Any help much appreciated before I rip off the cover."

Cozmo

[mcalvo]

Cozmo:
My only suggestion here is not to take to long before taking the engine apart. If the problem is getting worst, would affect other parts than the ones that need to be fixed/replaced.

Hope this helps you, regards,

MC.

[AsylumEscapee]

ok I have a recurring problem that may be related to yours.
In my 96 Geo Metro LSI 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. 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.
Its going to take me some time to measure clearance and find appropriate washers to somehow fix in place (so they dont eat away and then break into peices 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 really trust lifters from the junk yard. 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 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...)

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