m30 / m90 curiosity question

rsporsche

rsporsche

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been wondering about this for a bit ... question is which engine models had single width timing chain, which ones had double width? can't recall anybody ever talking about it, but i know both exist.
m30 b28
m30 b30 <double 1974>
m30 b32
m30 b34 (US)
m30 b34 (euro)
m30 b35 <single 1989>
m90 <single 1979> <double 12/1980>
 
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My m90 has a single. From a 735i E23 Sept 1979
 

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My M90 has double chain. At least now and through out my ownership the chain has been double. Engine origin M535i Dec 1980.
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Sami
 

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SamiA said:
My M90 has double chain. At least now and through out my ownership the chain has been double. Engine origin M535i Dec 1980.
View attachment 220729

Sami
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Curious if you have the VIN on the engine. RealOEM shows the 1980 535i as having a single row. For all the cars I looked at on RealOEM, the double row sprocket is listed in the figures, but it is greyed out, and only the single row is actually shown in the parts list
Screenshot 2026-06-09 at 8.05.37 AM.png
 
a note from the engine maestro - @sfdon says that the early engines had 2 row chains and quit at some point as it wasn't needed ... and from then on it was single row.
 
ScottAndrews said:
Curious if you have the VIN on the engine. RealOEM shows the 1980 535i as having a single row. For all the cars I looked at on RealOEM, the double row sprocket is listed in the figures, but it is greyed out, and only the single row is actually shown in the parts list
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I do have it: 4145730

1781025116508.png


Sami
 
SamiA said:
I do have it: 4145730

Sami
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Very interesting that was a December 1980 car. That one comes up the same as my 1980 M90 (5549667, March 1980) as a single row in RealOEM.

And reading @rsporsche 's post it may be an obsoleted thing. I'll have to go take a look at mine again. It's been a long time since I had the valve cover off!
 
as Don mentioned, 2 row chains are harder to find. now that i think about it, my 1973 Bavaria had a single row chain (as i bought one to change, but decided against it) under the valve cover and my e12 528i and e28 533i had single row ... all 3 of my 2002 had 2 row chains
 
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