OMFG>> Doesnt get much worse..

[e30loverSC]

Brken rocker.. and i wasnt even drivin super hard.. Well idk what too do? any input? prices... parts where the hell do i start. Is this something i can do myself over time with some help..

[accident]

I paid something like $35 for the rocker arm and just reused the eccentric from the one that broke. If you do just the rocker arm all you need is the rocker and a valve cover gasket. Some people say to take the head off to do this, but I didnt bother and it worked out fine. If you've never done it before pick up a bentley manual (about $40) and read through it. It will give you step-by-step instructions. Good luck!

[DoriftuEvo]

I believe the need for removing the head depends on which rocker arm is broken. If you can slide the cam shaft out far enough to get at the rocker arm you need to replace you won't need to remove the head. I remember reading that if the broken rocker is on the intake side, the head will need to be removed. I removed my head before investigating the no removal option, so I don't know for sure. I like tearing things apart completely anyhow.

The job is time consuming, but not hard. Follow your bentley manual (step 1 is buy a bentley manual).

[SpecM]

at the very least, unplug the injector to that cylinder in the meantime (if you're going to drive it anyway)

[jlevie]

While perhaps a more common cause of rocker arm failure is operation at or above 6k rpm, I know of enough failures where high rpm operation isn't involved to have formed a theory as to why this happens. My theory is that rocker arms fail from impact loading that results from wear in the rocker arm, worn valve guides, excessive valve clearance, or a combination of those. With improperly adjusted valves being the most common cause.

Depending on what rocker broke, it may be possible to replace the part w/o removing the head. It usually isn't too difficult to replace rockers on cylinders 5/6 with the head in the car. By lifting the front of the engine any of the rockers can be replaced. But getting the rocker shafts out with the head in the car can be a real bear, and you'll usually destroy the shafts in the process.

I think it a lot better to pull the head and give it a refresh. That would mean at least a valve grind and new seals, but it could include new guides, new exhaust valves, some rockers and shafts. Or just get a rebuilt head.

[JGood]

While perhaps a more common cause of rocker arm failure is operation at or above 6k rpm, I know of enough failures where high rpm operation isn't involved to have formed a theory as to why this happens. My theory is that rocker arms fail from impact loading that results from wear in the rocker arm, worn valve guides, excessive valve clearance, or a combination of those. With improperly adjusted valves being the most common cause.

I'm guessing too loose of valve adjustment would cause the "impact wear" you were talking about? That makes sense. Makes me want to recheck my valves on my m20 track car...

[jlevie]

I'm guessing too loose of valve adjustment would cause the "impact wear" you were talking about? That makes sense. Makes me want to recheck my valves on my m20 track car...

That is exactly what I'm thinking. Furthermore I think that wear in the rockers and valve guides increases the risk.

I adjust the valves for 8 thou clearance on a cold engine. While it is normal to hear a slight clicking from the valves on a cold engine, they should not make noise once the engine is up to operating temperature. If you hear clicking from the valves when at operating temperature and they are correctly adjusted it is time for a head rebuild.

[JGood]

Interesting. What does the factory spec call for, .010 cold, .012 warm? I am fairly certain my valve guides are worn (as with any 100k+ mile head), but what do you mean by rocker wear? The shaft? Or the rocker itself, where it contacts the shaft and/or the eccentric?

[Julien]

i've always read that the heat expansion of the raised lettering causes failure.. so far everyone i've seen has been throught he raised lettering. Some autox/track guys recommend grinding the raised lettering off.

to the OP.. if the it's cylinder 4,5 or 6 you can do it yourself. I replaced only the broken one on my car and 3 years later it's still fine

[bostonbmw]

I had #3 rocker on the intake break on me. If it is on the intake side you can slide the rocker shaft out through the cam sprocket be careful not to damage the shaft. I believe I pulled the radiator and moved the AC condenser down a little so I could slide the shaft through the front of the car.

I have 2 brand new rocker arms $30 shipped for both

http://www.r3vlimited.com/board/showpost.php?p=1654842&postcount=1

[JGood]

i've always read that the heat expansion of the raised lettering causes failure.. so far everyone i've seen has been throught he raised lettering. Some autox/track guys recommend grinding the raised lettering off.

I've heard of people polishing them, to remove the microscopic peaks/valley in the surface, since stress fractions can start there. So that makes sense too.