Rocker Arm


#1

I had a rocker arm failure this past weekend, the pad that rides on the cam came off and at least one more looks to have heavy wear on the pad. I replaced all of the rocker arms last year when I had one break with the Heavy Duty rocker arms from Bimmerhead, not sure if they get them from IE, but they do look the same.
Not sure where to go from here, may just go back to using OE.
Open to some ideas.


#2

There’s been lots of rocker arm threads here over the years. There’s no solution that has been free of problems. I am currently using IE HD rocker arms and they’ve worked fine for 4-5yrs. Other folks have had problems with them. There’s never been any attempt to gather any data, that is to say…

ID the different kinds of rockers in use and get some #'s re. failure rates of each type. This is made harder because it’s not always clear who made the rockers that were sold to you by BMW or a reseller. Or that FEBI, just to choose an example, rockers made one year might have been better or inferior to a different year.

There’s also processes that the rockers can go thru. One guy might smooth out the casting marks on a rocker or even polish it because smoothness reduces surface micro cracks that lead to fractures. Another guy might use a small hammer to peen a surface and, in so doing, work harden the surface.

Neither of the above two process are really legal, I imagine, but no one’s likely to care about those kinds of subtle things one might do to make their rockers more durable.


#3

The problem, as I see it is none of those processes you mentioned will solve the problem that I had. I had the cam pad come free from the rocker arm. I was lucky that it did not go into one of the oil drain holes, that could cause major damage. I feel that I need to replace all of them just make sure that I don’t lose another one.


#4

RE. what I mentioned won’t solve your problem. Maybe I misunderstood your problem. Sure, gathering info won’t replace your rocker. But what you seemed to be asking for is suggestions re. durable rocker arms. My answer was that you weren’t going to get hard info only anecdotal experiences because no one I know has ever gathered hard data that accounted for all the variables.

What I can tell you is the Metric Mechanic did a bunch of testing on rocker arms and found that the IE HD rockers were be far the strongest. But later there were some problems with those rockers, the exact nature of the problems I can’t seem to remember, and MM quit using them. If Rich Bratton sees this thread, he’ll probably chime in because he likely remembers what the issue was. Maybe they were chewing up cams?

That said, I would guess that MM generally uses high lift cams which would shove the rocker into the cam harder then our OEM cams so maybe we’re dodging the problem that MM found. I’ll send an email to Rich and point him towards this thread.

The IE rockers do have a history of losing their pads. One thing you could do is confirm that the rockers are indeed from Ireland. Then take some pics and send them to Jeff Ireland (jireland at earthlink dot net. A couple guys got their rockers replaced this way. If they aren’t responsive, get in touch with me. Twice now I’ve had to get involved to get a rocker replaced for someone because IE did seem too interested in helping. I’m the guy that got IE’s rockers “legal” for us and there were lots of conversations with Jeff that led up to that.


#5

IE HD rocker arms do in fact have a problem with the foots coming off. My engine failure at Roebling last year was the direct result of this; the pad came off, dropped into the pan, started bouncing around and destroyed two piston skirts, banged up the connecting rods, and pitted several of the cylinders. The entire engine is now garbage…

The problem with the IE HD rocker arms is with the steel pad to foot connection isn’t designed well. For whatever reason, the pads tend to come loose. The pads also tend to be machined in a way that creates a small ridges that scrape the oil off the cam. You can remedy with emery cloth and polishing.

In reality, the Febi rocker arms (~$13 each) are good enough. They aren’t as strong as the OEM BMW (~$46 each) pieces, but they should be reliable unless you frequently mechanically over rev or have week valve springs.

To increase the rocker arm fork strength, you can shot peen. It’s a pretty simple process and you essentially blast with large glass beads.


#6

Thanks Guys for your responses. I got my HD rocker arms from Bimmerhead, I sent them an email to find out if they came from IE, but I have yet to hear back from them. I may contact Teddy at MM to see what they are using.


#7

I used the Febi arms for about 15 years without failure, both on my motors and others I built. However, I spent good time removing the casting flash and polishing the arms to remove stress points. YRMV