885 head oiling differences


Other than the Daytona race last year, I’ve been running a .020" over engine that I built while I was living in Kansas. It had 14 or so race weekends on it and dynoed at 158 WHP at Road Atlanta last summer during the event prior to the East Coast Nationals. This background is important because it’s a miracle the engine was even running…

I refreshed (complete tear down) the engine over the winter using my standard procedures with the only difference being the addition of Ireland Engineering HD Rocker Arms. When I disassembled the engine, I took note that there was virtually no wear on the pistons, bearings, cam, the piston ring gaps were unchanged, but the intake rocker arms had wear that reduced valve lift by about .030". The exhaust rocker arms had no wear and I didn’t think much of it.

At Roebling Road this weekend, the engine was very strong for the Lightning race. All morning long though, I kept thinking the valve train didn’t sound right and acknowledged to myself that I would re-check valve lash prior to the next race. In my experience, valve lash does not change during the engine break in process, but there are always anomalies. Anyway, I lost power during the the Thunder race and pulled into the pits.

After I pulled the valve cover, I found significant rocker arm wear and complete failure on one rocker arm foot. However, this isn’t a defective part issue and the Ireland HD Rocker Arms are in fact reliable pieces; I just had a problem with my oiling system. After replacing the rocker arms, I started the engine and found that there was no oil passing through the oil spray bar. Today in the garage, I figured out that my cylinder head is in fact an 885 cylinder head from a 1988 Super Eta and it does not have the same oiling provisions that come standard on the 325i cylinder head. By drilling four holes, you can modify the Super Eta 885 casting to work well, but I didn’t realize it was a Super Eta piece during the original build and never made the modifications. Other than the oiling holes, the head is identical to all 885 cylinder heads.

So, the funny thing about this failure is that I ran this engine, and it ran very well for 14 or so weekends without oil moving through the oil spray bar or the oil intake side rocker arm shaft. I guess BMW builds a very hard rocker arm!!!

After discussing with Andrew at Ireland Engineering, Ireland is replacing the Rocker Arms at there expense and planning to examine and improve their design as necessary. I my opinion, the pad on the Ireland piece may not be as hard as the OE piece, but Ireland’s piece is much more resistant to over rev breakage and hard enough to last with proper oiling.

Rocker arm kabob

Cam wear

A standard 885 casting next to my 885 Super Eta casting. The red circles mark the the locations you must drill to create the oil passageways.


wow, I can’t believe it lasted that long


Yes, it’s amazing it lasted. To be clear, the engine lasted 14 weekends after I originally built it a few years ago, but only made it one day after I refreshed it this winter.


When you built it the first time, were the cam and rockers new or used parts?


It was a new cam with new OEM rocker arms during the original build; I re-used the cam but replaced the rockers during the refresh.


Being old school, when the govn removed ZCCP from oil, I started adding MSO2 to my oil. As an extreme pressure lubricant that will stay in suspension in the oil and pass through the oil filter, I got very good cam/lifter lubrication. Obviously it probably would not have worked in this case… The oil spray bar lubricates the cam/rocker interface, not the oiling holes in the head.The spray bar receives oil from each end of the head and is metered by the slots in the end cam bearings. If you have this type of wear, you have problems with the oiling spray bar, not the holes in the head. Also, the super ETA cam is also 7 bearing so why the hole differences???


Have heard of rocker pad hardness problems in aftermarket rocker arms…not Ireland specifically…but heard something about them being too hard??

Just strange that the stock arms lasted 14 weekends then the problem?



Al, you make a good point. The OEM rocker supplier certainly has the pad material science perfected.

Chuck, your point on oil is good as well. I was running Redline Racing Oil (very high ZDDP) for the entire life of this engine with the exception of it’s first weekend (Charlotte 2012 if I recall correctly). I tried Valvoline Racing Synthetic oil that weekend and the engine seemed to lose power after I noticed near extreme oil temperatures; switching to Redline Oil masked the symptons. 3 years later, I understand why the engine hates long left hand sweepers even though it never loses oil pressure. It was relying solely on oil splashing around in the head to oil the intake rockers and that didn’t work well at Charlotte or Roebling. I doubt MSO2 would have helped because the rockers were essentially running dry in between right hand turns that splashed oil over the intake lobes.

To figure all of this out, I set up a test rig in my garage with an old engine bottom end with oil pump and a pan, bolted the head to the block, used a drill to turn the oil pump and and another drill to turn the cam while adding components to the head to see what happens.

All seven cam journals on the cam and the cylinder head are perfect condition. Interestingly enough and you may not believe this (I probably wouldn’t if I hadn’t seen it with my own eyes) is that only cam journals two and four were receiving oil supply (from the exhaust rocker shaft). In a normal 885 cylinder head, all seven cam journals receive oiling from the intake rocker shaft yet mine was not receiving the oil feed that typically comes from the fourth journal and the oil passage holes are present in most of the journals. My assumption is that the head essentially created a small sump that allowed enough oil to infiltrate bearing journals and provide adequate lubrication. Totally odd, but there is not other way for the oil to route to each of the cam journals and the cam journals were well oiled when I disassembled the engine each time.


Your picture showed your cam, but not the slots in journals 1 and 7. As the spray bar works, oil pressure on journals one and seven are passed to the spray bar every other engine revolution. If you add the spray bar to your setup, you should see oil pulsations spraying oil on the intake and exhaust rocker pads. If your cam does not have the slots on one and seven, you are not lubing your cam/rocker interface!!! (other than splash oiling)


Chuck, the cam has the slots, but neither the #1 or #7 journals had any oil supply to transfer through the cam and into the spray bar.


2, 4, and 6 were the ones without holes. ALL M20 heads oil 1 and 7…they must to send oil to the spray bar!!!


Chuck, I knew you wouldn’t believe me! A picture of a Super Eta OEM cam would probably help but I don’t have one and it appears that google doesn’t either. I agree that all M20 heads oil all the cam journals, but Super Eta 885 heads with 325i cams do not oil all of the journals. There are no oil holes in cam journals #2 or #6 on the Super Eta 885 head; yes, this is a head scratcher…

journal #2.

journal #6.

So how do these two cam journals get oil in the Super Eta configuration? Does oil move through the cam?

Below is a picture of a standard 885 casting cam journal #4. You can see that it has holes to provide oil to both the intake and the exhaust rocker arm shafts. If you look carefully, you can see a third hole on the exhaust side that goes down through the head to the oil supply on the top of the block.

Now look at this picture of the #4 cam journal on the Super Eta 885 head. It only has the supply hole that feeds the exhaust rocker arm shafts. Behind cam journal #4, you can see #5; from the looks of it, BMW intended to feed the exhaust rocker shaft through cam journals #3 and #5 as they are drilled on both the intake and exhaust rocker shaft sides.


Not that I don’t believe you…the lack of oil holes for the cam journals is not your problem! The spray bar is.


The spray bar was there until I removed it to figure out why oil didn’t flow. With the engine running, 75 psi oil pressure, and the oil spray bar installed, oil did not come out the spray bar. I swapped the entire cylinder head assembly, and oil pumped freely out of the spray bar on the different head.


Exactly. Your problem is the spray bar, not the lack of oil on the cam journals…without wear, obviously they got oil. Now find out why the spray bar is not getting oil with that head.


The lack of holes is still amazing tho, even if they weren’t the cause of the failure.