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Yup, I broke one, it was a new one…probably due to adjustment, or over rev at CMP turn 14…In many years of running M20’s I have never broken before that, keeping the stock rev helps I think. I know of people who have broken them on the street and at DE’s. I tend to think that older heat cycled arms should be fine. Mine broke right thru the middle.
Jim, I dont think you have anything to worry about. I would be wary of aftermarket ones myself.
Al
The original OE design was bad, but that was corrected at some point and the stronger arms are all that is now available as an OE part… Sorry, but I don’t know when the change is design was made. It could be that most, if not all, of the broken rockers were of the original design.
Steve D wrote:
If the rules don’t say you can, you can’t. So the only legal rockers are the factory pieces. Don’t confuse “increase performance” with “go faster” in all cases. If the IE rockers were designed with less opening (more metal) for durability, I would argue that is increased performance.
Besides, the specific “exact shape and size” in the now-superseded rule trumps the more general “meet or exceed” language in the definition of “replaced.”
Steve D.[/quote]
I know the rules state you CAN use a crank scraper, which by design helps durability, what is the difference here? It’s not going to make someone faster by having heavier duty (and probably slightly heavier mass) rockers. If someone really wants to deal with the “rocker reliability issue” (if there really is one), what’s to keep them from building a new head every couple of races? THAT goes against the idea of a budget series, but if it means the difference at the end of the season in points, someone may follow that path.
Yea, I broke mine at VIR. It started with a crack and I actually ran about half of one more session until the power was gone.
Original 21 years old part. Not only that, the valves were not adjusted for at least 60 track days that I had owned Mr. Junky until that point.
I replaced all of the arms with the new OEM parts and planning to learn how to adjust the valves.
My wife hates Mr. Junky as is. I can’t ask her to come and rescue me again at VIR.
[quote]our understanding is that at some point in time BMW changed the design so original rockers could be the inferior design as well as being old and fatigued.
bruce[/quote]
Bruce,
Do you happen to have this service update via BMW? I also heard Febi “redesigned them many years ago with an extra extrusion on the side to make them stronger.”
I apologize if I brought up a shit storm on the board; I was just looking at precaution parts. I understand there are those out there who are on either side of this debate; old rocker arms = are easily broken, new rocker arms = should be no problem.
But the case in point is; I am not talking about a lighter version or custom designed arms. Granted I am not sure who manufactures these arms; but if I am rebuilding an engine, I don’t want to do it again for awhile…
I’ve had a good friend with his 325is broke an arm at Sebring before, but one cannot say if those were replaced or under what circumstances.
I understand that if the rules do not state it, then it’s illegal but I highly doubt everyone who may be running ‘illegal’ rocker arms are now running Febi’s.
I don’t know the date that BMW updated the part but here is a reference:
http://www.e30tech.com/forum/showthread.php?t=40424
has some pictures of old stock vs. FEBI - in the 4th picture, notice the extra thickened rib under the 5828 in the FEBI version
From what I’ve read in numerous places, you really only need more expensive rockers like IE’s with high-lift cams or a raised rev-limit.
thanks,
bruce
OriginalSterm wrote:
OS -
Don’t interpret my post as opposing a future rule change (in spite of agreeing with IndyJim’s goal of rules stability). I was arguing in favor of rules compliance (and trying to help Bav3 understand how the rules are to be read).
If the rocker arms are a common failure point, by all means we should look at the cost/benefit of having a stable aftermarket supply of a more robust but more expensive part.
I am opposed to allowing ‘open’ rockers because that will lead to another needless hole in the rules. Some say that the gains are too small to worry about. If I can get one horsepower by changing each of 10 things…
I am satisfied that the stock part is robust enough for our purposes. Of course, if you bang off the rev limiter all the time and don’t keep the valves adjusted, failure is more likely.
Steve D.
I have yet to hear of the “new” Febi arms breaking in a stock motor. Has anyone else?
These are an improved design and are OEM replacements. I’m not sure why we are still having this discussion?
FARTBREF wrote:
[quote]Yup, I broke one, it was a new one…
Al[/quote]
Did you read this thread or just start posting stuff?
So we have Al with a broken new one, and Chi with a broken old one.
That is just in the SouthEast and just people I know. So hardly a major study, but that is why I bring it up.
For the record I put the febi oem ones in, and if one of them breaks right before I light my car on fire, I’ll rip all 12 out and throw them an whomever says “These never break”.
This obviously happens before the anger management seminar and the inevitable trigger of Jones’ roid rage…
Steve D wrote:
[quote]OriginalSterm wrote:
OS -
Don’t interpret my post as opposing a future rule change (in spite of agreeing with IndyJim’s goal of rules stability). I was arguing in favor of rules compliance (and trying to help Bav3 understand how the rules are to be read).
If the rocker arms are a common failure point, by all means we should look at the cost/benefit of having a stable aftermarket supply of a more robust but more expensive part.
I am opposed to allowing ‘open’ rockers because that will lead to another needless hole in the rules. Some say that the gains are too small to worry about. If I can get one horsepower by changing each of 10 things…
I am satisfied that the stock part is robust enough for our purposes. Of course, if you bang off the rev limiter all the time and don’t keep the valves adjusted, failure is more likely.
Steve D.[/quote]
I was just adding my 2 cents, not arguing for or against either side. And I agree that if it truly is identified as an issue, there may have to be a rule change allowing some “improved design” rocker that offers ONLY longer life.
If there is a rule change, it may effect people like me who are rebuilding an engine with all stock components. The fuel tank/pump rule change got me already…
IndyJim wrote:
Jim, I feel your pain.
I’ve given up on rules stability, and am now debating whether I want to crash on my car to get it ready for VIR, or just skip because it’s too much damn work to meet the new rules, and i just don’t have the time to wrench.
But in this case, I think that spec’ing OEM rockers is a good thing. The magic dyno isn’t going to happen, so keeping these motors similar is going to depend on keeping the parts the same.
I have broken 2 rockers. Both times, “Adjust valves” was on my to-do list. I honestly believe that if you adjust them once every few months that you’ll be ok. I’ll let you know when I break on that was well adjusted.
-Vic
[b]victorhall wrote:
I honestly believe that if you adjust them once every few months that you’ll be ok. I’ll let you know when I break on that was well adjusted.
-Vic[/quote]
Dang,
I just learned how to change my own brake pads, now I gotta learn how to adjust valves four times a year?:woohoo:
DB
IndyJim wrote:
[quote]FARTBREF wrote:
[quote]Yup, I broke one, it was a new one…
Al[/quote]
Did you read this thread or just start posting stuff?
So we have Al with a broken new one, and Chi with a broken old one.
[/quote]
Way to selectively quote…
Rev. Alonzo wrote:
I don’t think that they are an issue if maintenance is kept up.
John - It’s really not hard at all, just easier with an extra set of hands.
I’ve always been told that the BMW spec torque is part of the problem. I haven’t encountered the busted rocker arm (yet), but I attribute that to the fact that mine are not as tight as what Bentley calls for
I’ll give my last shot on this since this wasn’t intended to change the rules or make anyone angry. I’m simply saying that no one on this board knows why these break, if one design is better than the other, etc. Meaning has actual empirical evidence (not gut feel).
Here is the thought process I went through making the decision based on facts:
These rockers break. How do I know?, because I’ve been around when it happens and have seen it.
How can I prevent that from happening? - buy billet.
Is billet legal? Ask, and ‘was’ told yes.
Now the rules change. Fair enough.
Send to your E30 friends that don’t race SE30, or I’ll keep for my KP build.
http://cgi.ebay.com/ebaymotors/ws/eBayISAPI.dll?ViewItem&item=260352817093&category=107063&viewitem=
IndyJim wrote:
[quote]
Send to your E30 friends that don’t race SE30, or I’ll keep for my KP build.
http://cgi.ebay.com/ebaymotors/ws/eBayISAPI.dll?ViewItem&item=260352817093&category=107063&viewitem=[/quote]
Wow. I had no idea that better rocker arms were so expensive. Ouch.
IndyJim wrote:
[quote]I’ll keep for my KP build.
[/quote]
I always knew you were a time trialer at heart! 
I just want the possum fur coat that Al makes for national champs. That makes Geegar’s trophy chairs look pretty lame in comparison.