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Thanks to the advice of a couple people here I just got done removing the rocker arms through the front of the engine bay without head removal. As I throw away the “Febi” brand junk away, what are people running that meets spec and doesnt break? I think I had heard BMW had an updated model that bimmerworld sold or possibly sourced from the dealer? ANy help or recomendations would be appreciated.
Thanks
The whole rocker arm thing is a subject of some contraversy. As long as an aftermarket rocker arm looks identical to an OEM rocker, well, except for it being broken, it should be ok.
Ireland sells a number of different rocker arms. Off the top of my head, one looks identical to OEM, one looks similar and one is a billet rocker. So that’s “legal”, “not really legal”, and “obviously not legal”.
I’ve not heard anything compelling about aftermarket “OEM lookalike” rockers being better or worse than OEM. Metric Mechanic sells a rocker arm for about 2x OEM price that is actually an OEM rocker arm. What they do is buy a bunch of OEM rockers and then inspect some key areas of the rockers that they’ve found to be troublesome, and keep only the best ones to resell.
Fish Bratton did some interesting work analysing rocker arms and found evidence that geometrically they seem to vary a surprising amount. That is to say if you get a dozen rocker arms from any single mfr and carefully plot the valve lift curves, you get differences. It’s not that one mfr makes rockers that give you more lift, it’s just that there’s some variation in the manufacturing process. If someone was determined to get performance advantage they’d buy 100 rocker arms, plot the lift of each and then keep only the best.
So where does that leave you? Well, you can buy rockers from MM or you can buy OEM (or aftermarket lookalike) and hope for the best.
My brother has a 10lb bag of used oem e30 rocker arms. I’m sure you can work out a deal on some oem ones. You can probably tell him what i.d. you want. I’ll email you his number.
Used rocker arms are a bad idea! Not only are they fatigued, but they have reduced lift even if the pad wear is ever so slight. I literally threw out 75 or so used rockers today because ALL of them had reduced lift and some as much as .030". Rockers that visually looked good, had .010" less lift than a new OEM unit. It sucks that they are so expensive at $37 bucks each!
Nothing wrong with the Febi rockers…BMW’s OEM supplier. You MUST, however, blueprint the rocker to make it last. That involves removing all the casting flash and polishing the top surface. I have not broken/had one broken in 10 years. Chuck
So this Bimmerworld Rocker appears to be OEM, I wonder how this price compairs, anyone runt hese?
http://store.bimmerworld.com/genuine-bmw-m20-rocker-arm-p659.aspx
[quote=“ttiede” post=66176]So this Bimmerworld Rocker appears to be OEM, I wonder how this price compairs, anyone runt hese?
http://store.bimmerworld.com/genuine-bmw-m20-rocker-arm-p659.aspx[/quote]
These are the OEM rockers and the BW price is about average. My dealer gives me a good discount and I can get a little cheaper, but only by a few dollars each…
Richard,
If I buy these, am I to modify them somehow or polish or grind anythin g around like you and others had mentioned or just install and go? I have never done anything but install them but have noticed people working with the casting etc and that is all foreign to me.
[quote=“ttiede” post=66194]Richard,
If I buy these, am I to modify them somehow or polish or grind anythin g around like you and others had mentioned or just install and go? I have never done anything but install them but have noticed people working with the casting etc and that is all foreign to me.[/quote]
I would think that any modification to the stock piece would be illegal without a rule change.
Blue printing is an acceptable practice, as is balancing. All you are doing is removing the casting flash (better known as “break me here”) and dressing the sanding marks. Chuck
Richard, if the Ireland looks the same (and, hey, I’m a rules guy trying to catch the silly non-spec stuff that really can’t be enforced ),it seems that I’d want the .015 extra lift.
For “really can’t enforce stuff” check out the “cam” that could be made with a special rocker foot profile at detroit cnc maching video (do a web search).
I’d say the rules enforcement guys need a horsepower rule, but I don’t make the rules and have grown tired of beating my head against a wall.
RP
I had been curious about these. Not legal but only 5$ more than the febi ones.
[attachment=1849]rockers.PNG[/attachment]
Here is a picture of the IE HD rocker arm (right) and an OEM rocker arm (left) that I took today. Visually, they are much different.
[URL=http://imageshack.us/photo/my-images/594/20120529155303428.jpg/]
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Using a dial indicator, I measured valve lift every ten degrees (measured at the crank) for an IE HD and OEM rocker and plotted the results in Excel.
As you can see, the IE HD rocker makes a bit more lift. It would be nice if they did perform similar to the OEM rockers as they are much cheaper, but they do not and IMO are not authorized within our rule set.
Balancing only is an acceptable practice acoording to the ruleset, and stretching the balancing rule to the rocker arms is a “stretch.” 
Removing casting flash and polishing the surfaces may violate 9.3.1.2.7
I hear you though and the rules should be modified to accept either a spec type, or specify what can be done. It’s obviously an issue that need to be addressed. Anything that can be more of a “set it and forget it” is great in my book.
A letter currently in the works in regards to the legality of the IE HD rockers.
As is my understanding,
the IE HD rockers were ‘formally’ outlawed a couple years ago. Since
then, however, I’ve found a good percentage of people running them and
they are increasingly being accepted as being ‘legal’. I’d like to
know how to get in contact with the correct people to state our case
that they should be formally legalized.
Our position is that there is no inherent performance benefit to running
these rockers since the geometry is unchanged and it still follows a
similar construction as the original rockers (cast aluminum). It is
simply a stronger rocker made to fix the inherent problem (weak
eccentric arm) on the M20 engine, much akin to the ‘legal’ Febi 'design
2 rockers (you can see the comparison of the ‘weak’ area on the OEM,
febi II’s, and IE HD’s in the last attached picture.). Our argument is
that we should be categorized as an aftermarket supplier just like Febi
is, especially since they have also actively modified the rocker casting
design in much the same way we have (only that we’ve taken ours one step
further). If the Febi’s are a formally legal rockers, then our should
be just as legal.
The IE HD rockers have been independently verified at this point by
another prominent figure in the spec-racing community (actually a semi-competitor) to be %30-%50 stronger than their OEM Febi counterparts. They also follow the SpecE30 ethos of being affordable (priced similarly to the OEM/Febi replacements).
I’ve got this covered and I’ve a good track record with rule changes requests. I’ve been in contact with Ireland, and also Metric Mechanic who did the testing of the rockers. Rich Bratton set the issue up for success with an incredibly timely suggestion as he helped the Carter, the national series director, replace his (Carter’s) broken rocker at RA this month.
Rule changes get submitted in the Fall, we start screeching “where hell are the rules” in Jan, and then a week or two after the first event the new rules come out in mid Feb.