oil spray bar differences...

[PatAllen]

anyone ever noticed theses small differences in between the oil spray bar into the cylinder head ?

and why it actualy spray in between two cam lobes instead of right on it ??

the shiny one is from a late late e21 1.8, the other messy one is from a junk 1974 Tii motor. I have one too (not pictured) with only small round holes, still only squirting in between each cam lobes, not directly over them.

two differences: the spray hole next to the timing chain is much large on the late design

also the late design has its hole more rectangular and in line with the tube, my only guess is it squirt "larger" so it can reach potentialy the two lobes...i am wondering if i had one bar drilled with two tiny holes right over the lobe instead of in between two...

among the ones i have, there was 2 with cloged holes for the timing chain...worth a check when you rebuild a motor...

[aa/fd]

This is all speculation, but you like I assume that an oil hole for each would be a proper design. But sometimes in application even the best engineered designs have to change. It could be as simple as the small holes like you suggested might clog too easy and if they were large enough to not clog they might flow too much. I essence too big a leak for the oil pump at idle. Another reason might be fewer holes cost less to make. Bean counters always win when you are over budget. The design obviously took a change for cost issues, as the crimped design would be cheaper to manufacture than the tube with the swedged plug. Could be as simple as the low bidder won the new contract for supplying spray bars. Interesting and somewhere in Germany a retired production manager in charge of M10 engine assemblies knows the answer.

[tjones02]

Ha, you should see one of the earliest versions with the banjo fitting in the middle and the pipes welded to it... things definitely got cheaper to make as these cars went through the model years.

If I have in laying around here I'll snap a picture for ya...

[PatAllen]

i had all 3 connected on my parts cleaner tub. The later design realy sprays in a steep angle on the cam gear, almost on the chain itself, while all others sprays straigh.

The direction of the holes does not seems to change the spray patern at all.

I know my test was not using oil (parts cleaner solvent)...