123 Distributor failures from oil?

I re-torqued the head bolts today to stay busy and keep my project moving while I wait for parts (again), and noticed that the vacuum line on my 123 distributor had oil on it. I pulled the distributor and dis-assembled it to see how much of an issue there was.

Just a light film on a few parts so far, but the presence of oil in the vacuum fitting has me wondering if the presence of vacuum is pulling oil up the shaft.

I am thinking that I may not re-connect the vacuum advance. Prior to the rebuild I did not have vacuum connected and had not noticed any oil, but I admit that I wasn't looking for oil until you started this thread.


123 Dist oil between plates.JPG
123 Dist oil at top of plate.JPG
123 Dist oil at vacuum.JPG
 
That’s strange to see it at the vacuum port. Did you check the little blue tube inside that it is still connected to the circuit board?
 
Stevehose said:
That’s strange to see it at the vacuum port. Did you check the little blue tube inside that it is still connected to the circuit board?
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Well, that was a miss for me. I did not, but may pull it apart again and take a look. There is a clear cap on the side of the distributor, I wonder if that is removable to use the endoscope...

I must admit that the issues with the 123 are frustrating for what is presented as a high-end product.
 
Stevehose said:
The clear cap is the bluetooth light so I would avoid that
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Saw your not too late, I pulled it, but needed more access for a good look so I disassembled the unit again. All seems to be connected as it should be and no oil seen on electronics. That would seem to indicate that the oil is migrating up the shaft despite the machined shaft.

123 Dist electronics level 2.JPG
123 Dist electronics level 1.JPG
 
I have 300 miles on my most recent fix attempt (replacing the grooved "improved" shaft with the original non-grooved one, the double seals, and larger diameter valve cover breather hose). No leaks yet. There, I just jinxed myself.
 
I purchased with the grooved shaft so that isn't an option for me, but will consider re-installing the original distributor if needed.
 
And not reconnect the vacuum?

I looked at the beginning of the thread and Gary just had a cap on his port ( but still had oil migration)

Steve, have you always had the vacuum connected?

Hard to believe this would contribute to the cause/reason but mine is not connected or capped and haven’t seen any oil……..yet.
 
DWMBMW said:
And not reconnect the vacuum?

I looked at the beginning of the thread and Gary just had a cap on his port ( but still had oil migration)

Steve, have you always had the vacuum connected?

Hard to believe this would contribute to the cause/reason but mine is not connected or capped and haven’t seen any oil……..yet.
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Yes I am running vacuum advance but the connection goes to a sensor on the motherboard so that should not have any effect on oil intrusion.
 
When I built my m10 engine and ordered the 123 from a friend who is a dealer for them, he asked if I wanted the version that had the helical milling reversed so the oil never comes up on my dizzy. He mostly builds Porsche engines and told me that the typical 123 is made to be turned the opposite direction than the M10 turns. So they make custom versions for this circumstance specifically to prevent oil intrusion. I think it was an extra $100. I don't know if this scenario is relevant to an M30B35. My E9 build will run wasted spark and stand alone ECU so no distributor for me. But it's worth asking 123. No issues at all in my 2002.
 
Rudy3.0CS said:
When I built my m10 engine and ordered the 123 from a friend who is a dealer for them, he asked if I wanted the version that had the helical milling reversed so the oil never comes up on my dizzy. He mostly builds Porsche engines and told me that the typical 123 is made to be turned the opposite direction than the M10 turns. So they make custom versions for this circumstance specifically to prevent oil intrusion. I think it was an extra $100. I don't know if this scenario is relevant to an M30B35. My E9 build will run wasted spark and stand alone ECU so no distributor for me. But it's worth asking 123. No issues at all in my 2002.
Click to expand...
Yes, @m5bb was the one who made that helically milled spindle possible. Works on all BMW M10 & M30 engines like the original Bosch Distributors. That stops all oil from blowing past the 123 dual O-rings. I have123s in Athena 1973 3.0 CSi, Vern 1973 2002Tii & Veronika 1968 1600 Cabriolet all have the milled spindle.
 
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