123 Distributor failures from oil?

sfdon said:
Time for a splash shield at dizzy?
Click to expand...
Yes i was thinking something internal to blunt or relieve the force. Something also tells me that perhaps without vacuum, the valve cover vent may not relieve enough pressure at high revs and therefore the next path of least resistance is the distributor.
 
Stevehose said:
I am reviving this thread as I am now battling this issue. My theory (besides the crank pressure one as noted above) is high oil pressure and I am asking the experts to confirm or debunk this possibility.

When I rebuilt my engine, the oil pump was also rebuilt and it works great. Hot oil pressure maxes out about 60psi at 4k rpm or so and 22 at idle. But after the engine had broken in and been running for a while, I noticed the dreaded oil seepage between the sandwiched circuit boards and oozing out of the cap. I removed the 123, cleaned the circuitry, and installed a new seal and bronze bushing. I already have the helical groove "upgrade" shaft - which now obviously isn't enough to hold back the oil. Yesterday, 6 weeks later, I noticed the issue is back after only a thousand miles or so.

My suspiscion started after the engine rebuild and before starting for the first time. I spun the engine with the starter (no plugs) to see if I had any oil pressure and if so, build it up before the first real start. I did this without the distributor in place and when I cranked it, oil shot out of the dizzy hole across the garage - not a drizzle, a significant shot that cleared the fender. I noted back then that if I ever had 123 oil intrusion that this may be the source. So here we are.

In summary:

1. I have the grooved drive shaft
2. I have new a bronze bottom bushing and shaft seal (looks like a mini transmission selector rod seal)
3. I have oil seeping before and after the latest 123 rebuild.
4. I have the valve cover breather hole venting with no restriction (other than the diameter of the hose attached to the fitting - hmmmm.....).
5. The only thing that has changed is the engine rebuild with higher compression pistons (10:1) and oil pump rebuild

Therefore, if it is the crank pressure:
1. High revs and/or high compression pistons overpower the ability of the valve cover hole to vent, possibly with, certainly without vacuum from the stock air cleaner, thereby driving oil up the 123 shaft past the groove and seal. Interestingly enough, I have little to no condensed oil at the bottom of my valve cover vent tube so a large amount of blowby is not evident. I may try a larger diameter hose but I suspect this will not have any effect.

If oil pressure:
1. High oil pressure, especially cold 20W50, drives oil up the 123 shaft past the groove and seal

Any thoughts on the above? I love the tech of the 123, and given BMW is the only engine with this issue as far as I can tell (I've searched other forums), I'm not ready to fully blame the 123. Yet.

I'll be cleaning this again AND thinking of a possible fix.
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Steve, Great to see you are driving again. I'm not on here as much as I have 3 other cars to take care of.
I did get this notice.
I did install a catch can below my Webbers as I was suspicious of back pressure.
I found multiple stories on 2002 FAQ about problems with the 123. That's what put me on to running issues I was beginning to have.
My engine never quit running just would not run well and you start chasing problems you don't think could be a distributor.
Wanted to drive the car some longer distances, worried me with the 123 even after the upgrades.
It was failing again so I rebuilt my original distributor and installed a Pertronix electronic ignition.
Dialed in about 30 degrees advance. That was more than 2 years ago, no problems since.

Interesting about cranking the engine without the dist. and see oil shoot out. Never tried that.
I see the benefits but got tried of problems and potential problems.
My M30 runs flawlessly with a stock dist.
Not sure the 123 is worth the hassle.

Here's a interesting note for guys with high performance engines.
When I inspected my spark plugs I was not happy with the color.
Too rich.
Started search for hotter spark plugs.
No Bosch, no NGK although they had had a hotter plug but now NLA.
Champion had a huge heat range, bought some, inspected them and have been running for 2 years.

I'll pay attention and see what you determine.
I like the KISS program.

Gary
 
Stevehose said:
I am a fan of NGK BP5ES which is one range hotter than “stock.” Non resisted ones can still be found on eBay. Did you go hotter than that? Webers do like to dump the fuel!
Click to expand...
I also use those plugs. I find them available in some of the regular places. Just have to search for them under the NGK stock # - which in this case is 7734 for BPR5ES.
For example - Rock Auto has them... just do a search for NGK 7734 (BPR5ES) or 7832 (BP5ES). Both on RockAuto.com
Here is a page with more info on NGK plugs than can ever read though.

Decoding Spark Plug Part and Stock Numbers - NGK Spark Plugs

We break down how to decode the part number and stock number on your NGK spark plugs.
ngksparkplugs.com ngksparkplugs.com
LOL - There is a link on that page that has all sorts of info on how to decode their part numbers and then also get the stock numbers (which many places use to list these plugs instead of the alpha-numeric part numbers).
Been using NGK plugs in about everything I drive since the early 1980's. I've had very good luck with them. I even use them in my power equipment and boat. :)
 
Stevehose said:
I am a fan of NGK BP5ES which is one range hotter than “stock.” Non resisted ones can still be found on eBay. Did you go hotter than that? Webers do like to dump the fuel!
Click to expand...
Yes, I ran that NGK. They were ok but not quite hot enough. I don't have the Champion number in front of me but they had a much bigger selection.
 
Working through the oil pressure theory:

TLDR: My thoughts are that this is not the cause.

Thanks to @m5bb this engine oil flow diagram is great. It shows that there is a direct path to the distributor drive shaft gear (points 21 & 13 area) where it then splits to go to the front half of the cam and sprayer bar. After the distributor drive gear, it drains into the chain tensioner reservoir then overflows back down. The yellow indicates oil path, and goes directly up both the front and rear of the engine under pressure:

IMG_5446.jpg



The oil goes through the distributor drive shaft as seen here, out the front and side of the machined end, then is allowed to pass out the bottom of the bore in the cover where it then goes to the bottom of the well where the distributor is inserted:

IMG_5443.jpg



Oil comes out of the hole where the red arrow is then out where the green arrow is at the bottom of the distributor tube.

IMG_5442.jpg



Oil comes out here at the bottom of the distributor tube:

IMG_5445.jpg



So if oil was being forced out of here under pressure up towards the distributor gear/seal, then this pressure could be relieved by removing the lead drill plug circled with the arrow in the previous picture. It is plausible for the "shot" of oil coming out of the dist mounting hole when I spun the engine to have originated from one of these bottom holes.


But since there is a large opening which empties down into the front of the head, past the timing chain and into the oil pan, I don't see how enough volume and pressure could build up for it to be the cause. Maybe by removing the lead plug it would keep the oil level lower by the distributor’s gear thus keeping it from being forced up from crankcase pressure. @sfdon please correct me if I am missing something here:

IMG_5444.jpg



So my next step is to test the crankcase pressure theory by attaching a pressure gauge to the valve cover vent hole, run at various speeds, and see what we find there. Comments?
 
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Deep dive I contemplated but never attacked.
Remember I mentioned that some 2002's had same problem. Dist in rear on the M10.
I really don't think there is a lot of crankcase pressure.
With engine running you can barely feel any air through the hole on the valve cover.
But I do know these engines will throw oil out the hole at constant high RPM's.

I did an autocross in second gear. From 3500 to 7000 over and over. There was a puddle of oil on the ground when I parked the car.
This was before I put the catch can on.
The guys that race with the M30 all use catch cans but I never seen any use more than the valve cover hole for breathing.

See what you find out.
Gary
 
m5bb said:
I really don't think there is a lot of crankcase pressure.
With engine running you can barely feel any air through the hole on the valve cover.
Click to expand...
agree, I'll drive it with the gauge on my windhshield wiper and see if there's anything.
 
When the oil system was "in design" stage, several calculations like flows or pressures have been taken according to specific oil type to be used with. Diameters, dimensions are optimal for specific viscosity level at working temperatures.

Oil quality has evolved over time. Engine oils ale much different to the ones available in 60's when the engine has been designed. It does not mean old engine will not work properly on the new oil.

Many owners of classic cars are using modern oils as they are cleaner, less viscous (more towards water flow) and often contain several additives.

I'm not sure it is the reason, but I can imagine that some old ways of sealing working for 20W40 will not work as efficient for 05W40 (not taking into accounts additives responsible for cleaning, anti-oxidation, dispersion. Also holes, tollarances and diameters will show different performance on different oil grades.

Different Owners have different theories and experiences about the type of oil to be used in old cars. Some are using high performance (e.g 10W50), some standard (e.g 20W40) or very modern, low viscosity engine oils (0W20). Taking into account different condition (mileage) of M10/M30 and several, different modifications, each of the users can experience oil leak at different locations or no leaks at all.

Just a theory...
 
Update. I am pursuing the pressure theory.

The valve cover hole is ≤15.75mm ID wide depending on where it’s measured.

IMG_5452.jpeg



When I put my Weber sidedraft filter system back on and broke in the rebuilt engine, my valve cover vent tube was only 7mm ID. That’s a large reduction in flow!

IMG_5456.jpeg



Recently I have gone back to running trumpets (I like the induction noise for the time being) and the hose I have been using is 9mm ID. Also a significant reduction in flow potential.

IMG_5457.jpeg



Today I put a pressure gauge on the cover outlet and for sure there is pressure at high revs so I have made up a new section that is 14mm ID to closely match full flow potential of the cover hole and CSi elbow:

IMG_5458.jpeg

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With a glued in .5mm joining sleeve 3/4 around I get very little loss of flow from 14mm.

IMG_5460.jpeg


IMG_5461.jpeg


So from 7mm to 14mm is twice as much air flow from before.

I will now again clean the oil off of the 123 circuit boards and innards and run it for however long it takes to see if this has solved the issue. It only took 1000 miles or so before, with no oil residue in the hoses.
 
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For the record here’s how to clean an oily 123.

Take a pic of where the rotor is at TDC #1 cylinder so you can get it back close on install. I have mine like a stock distributor with rotor over plug number 1 even though technically it can be anywhere but I find this way easiest.

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Pull the distributor and remover the rotor. First signs of oil:

IMG_5465.jpeg



Punch out the lock pin to free the top piece from the shaft:

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Pull the top off and more oil. The washer will stick to the magnet. Clean and don’t lose it, put it back with same side facing the shaft. Take a pic of the top PCB so you don’t flip it on install. “BOT” faces up:

IMG_5468.jpeg



Pull the shaft out from the bottom, watch the washer. Note the reverse groove to “prevent” oil intrusion:

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Out comes the oil from the housing:

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Remove the 5 screws, pull the top PCB and now it’s getting ugly:

IMG_5483.jpeg



Separate the bottom PCB from the shaft and pull it a little away from the distributor housing so you can clean both sides. Mind the blue vacuum hose attachment if yours has this, I glued it in last time, make sure this is fully snug on install:

IMG_5486.jpeg



Use electronic circuit cleaner so as to not damage the components. This also dissolves the oil instantly:

IMG_5484.jpeg



Once everything is (gently!) clean, including the housing and gear shaft, assembly is just the reverse. Leave a very thin coat of oil on the shaft so it doesn’t tear the seal inside when installing it (rotate it as you push it in). Then start the pin with pliers, squeeze it almost all the way in then finish with the punch:

IMG_5489.jpeg



Last time I had the 123 out I wired a quick connector to it so I can get it off easily and also because I have it wired to a power strip under the light cover, not in the engine compartment:

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Install the distributor and use a timing light to match the actual timing in the flywheel timing ball window to your 123 curve at idle.

Not super difficult, but hope I don’t have to repeat (yet again) anytime soon!

Upper timing cover mod idea in the works…
 
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Steve, how can they call it 123 when it takes 15 steps to install?
Good luck with the pressure theory. I am known for explaining the flaws in theories after I see that they failed, but cheering for your theory on this one!

PS: Thinking ahead, if it is not pressure, what other force can move oil there? Coriolis? Capillarity? Compound interest? (Einstein said this is the most powerful force in the universe).
 
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