Has anyone ever seen this? Rocker arm shaft question

[sampayne]

So I broke a rocker a few weeks ago. I damaged the rocker shaft a little bit getting it out, since I did the job with the head still on the car. No big deal, I just got a new shaft along with the replacement rocker. I put the new shaft in along with the rocker and pretty much almost reassembled the head. Then I noticed the rocker wasn't sitting on the cam the same way is was before. It was shifted over a bit and not lining up on the original shiny wear mark on the lobe. I then inspected the other end and the eccentric was obviously not centered on the valve either. The rocker shaft was oriented the right with the retainer clip in the front, so theres no way the shaft isn't all the way in. I originally thought it must be some sort of QC defect and the shaft was machined wrong. I returned it and purchased a new shaft from a different site and manufacturer, in hope of not getting the same thing again. The new shaft came last night and its the same size/spacing as the other one. The notch in the shaft where the rocker retaining clip slides into is spaced differently than the ones that came out of my car. Here are some pictures comparing the two:




Another thing to note is the old rocker shaft from my car has a flat/smooth end in the shaft, whereas both replacements I bought have the hex head grub nuts in them. Not sure if that means anything. I've never heard anything about there being a variance in size of rocker shafts between different m20 heads, so this does not make any sense. I crossed check PN's from a euro 323i rocker shaft to a normal US 325i shaft and they are the same. I am completely stumped. Has anyone ever seen anything like this? Any help appreciated. Thanks

[TobyB]

All I can think is that it's not the correct side?
But that would be too easy...

t

[SkiFree]

[Old525i]

I had the same problem with replacement shafts for my 1990 525i M20 equipped car. The Febi set from AutoHausAZ just didn't match exactly like the factory original set. The marks didn't line up. I ended up returning them and following the advice from MM: reuse the old set after buffing them with steel wool.

[sampayne]

All I can think is that it's not the correct side?
But that would be too easy...

t

The retainer clip notch is not symmetrically spaced on the other side and is closer to the end, so they can only be oriented one direction. :/

I had the same problem with replacement shafts for my 1990 525i M20 equipped car. The Febi set from AutoHausAZ just didn't match exactly like the factory original set. The marks didn't line up. I ended up returning them and following the advice from MM: reuse the old set after buffing them with steel wool.

Yep, it sounds like they are just defects. I'm going to try to pull a shaft out of a 525i at a local scrap yard and use that.

[halesyeah]

4 years later these bad rocker shafts are still being sold. Got mine from Ireland Engineering. Look to be Vaico brand. They line up fine on the exhaust side, but are near 3mm off in the intake side orientation. Will be returning mine and just reusing the old ones after cleaning them up.

[digger]

TBH the OE ones are "only" twice the price so that's what i bought last time though you do need to get the screw in end plugs