d21 rocker arm destruction

[SavageD21]

hi fellow Nissan freaks. i just bought a 1994 Nissan D21 5 speed 4x4 with the ka24e. well it noticed it felt slugish and some weird problems so i bought a new maf clean some stuff, still nothing. so i popped my valve cover to check my timing and guides and to my surprise my rocker arms on my back 2 cylinders on my exhuast side are messed up. whats messed up is they lifters have a little brass shoe that is somehow attached to the iron and the shoe hits the cam lobes. well 2 of those have came of and my exhaust rockers dont hit the cam so it has flooded my oil with gas and it wont run right. how did this happen? do i need to replace the 2 others aswell? ill post pics when i can.

[seang]

Being familiar with the KA-E, I am not aware of any brass rocker-arm-to-cam contact shoes. My mind is telling me that brass-on-steel would wear out faster than steel-on-steel, especially in an area with so much friction, possibly even fast enough where the engine would not make it more than a few thousand revolutions before the brass surface started degrading rapidly; but I am only saying my thoughts. I don't have a PhD in engineering so take them with a grain of salt. It just seems wierd to me.