Rocker Arm Walked

[liquidgroove]

Last night I was doing some fun driving and took the engine up to 6500rpm. After slowing down, I discovered the engine had a horrible valve tick noise. This noise is much louder than the out of adjustment "valve tick". Fortunately, I was near by my house and baby the car home.

After open up the valve cover, I found the intake rocker on cylinder 5 had walked. It was no longer above the valve tip and was pressing on the retainer.

Fortunately, undo the retainer clip and reinstall the rocker arm seemed to address the issue. Engine was as quiet as before.

Anyone else had this happen before? Is this a "sign" of something going to break soon? Just like to get the issue fixed before it does break something.

[SpecM]

I would replace the rocker clip with a new one

[thereisnoyun]

I agree, this happen to me before. Get all new rocker clips. That would be the only concern.

[M-technik-3]

I would not be surprised if down the road the rocker arm fails. Suggestion maybe to shift before 6k and not redline an older engine.

[2.5-12]

theres nothing wrong with redlining and engine, no matter the age if it has been taken care of. going into the red, never a good idea.

I have seen 60k mile automatic convertibles with snapped rockers and I have seen 300k mile manual-red-line-it-every-day-M20B25 cars with original valve trains in pristine shape.

that being said, they do fail at about 6,800rpms in most cases. my good buddy Jeff has a chipped M20 vert' and it sees 7,000 rpm more often than it should. valve train is still fine.

[jlevie]

theres nothing wrong with redlining and engine, no matter the age if it has been taken care of. going into the red, never a good idea.

I have seen 60k mile automatic convertibles with snapped rockers and I have seen 300k mile manual-red-line-it-every-day-M20B25 cars with original valve trains in pristine shape.

that being said, they do fail at about 6,800rpms in most cases. my good buddy Jeff has a chipped M20 vert' and it sees 7,000 rpm more often than it should. valve train is still fine.

I've seen the same thing and my theory is that the big contributor to rocker arm failure is the repetitive impacts that result from a lack of timely and correct valve adjustments. On a street car that doesn't spend a lot of time above 5500rpm, adjust the valves at least every 10k. On a track or race car about every third of fourth weekend.

[2.5-12]

+1 and +1.

[M-technik-3]

See what you both just mentioned? Impacts, Well that arm did walk slightly so now it most likely has a stressed area where it normally wouldn't. Fail next week, I doubt it but you never know.

Edited for the grammar police.

[thereisnoyun]

See what you both just mentioned? Impacts well that arm did walk slightly so no it most likely has a stressed area where it normally wouldn't. Fail next week doubt it but it might never know.

grammer dude... I dont even understand what you wrote.

[M-technik-3]

I was typing quickly dude relax read slowly. Add a comma between Impacts, and Well. Add another after week.

[PxTx]

It could be a sign of weak vale springs too. If the spring is being lazy, the arm will have enough clearnace to walk. On a car which sat for a long time a few springs will remain compressed and loose some strenght. Fresh valve springs and seals?

I'm more familiar with BMW's as much as Audi 5 cylinders, but it doesn't look to hard to replace the springs.



For a reference, they are buried deeper in the head on an Audi.

[DJB]

Notice that on the Audi engine you can just gradually loosen the bearing caps and lift the cam straight up?

On the BMW head the rocker shafts and cam go through the casting and have to be removed from the front or rear. That means most work must be done through holes drilled in the dashboard or radiator....

[AlarmedBread]

If you pull the hood, unbolt the motor mounts and jack the engine up a bit you can slide the rocker shafts out the front of the head to change rockers.

However usually there are more underlying issues and you should just pull the head and give it a quick refresh.

[liquidgroove]

Thanks for everyone's input. I am gathering parts for 2.8L stroker right now. Will sure put new valve springs and retainer to the shopping list.