[bmw] Re: EI questions & suggestions.

[jkerouac <jkerouac@xxxxxxxxxxxxx>]

Hi Gregory,
    Sounds like you're researching this project well.
If you have the 40 degree advance distributor, that will be good.  The 
Allison optical ignition is know nto have reliability problems.  The 
Mallory is a power pack with a magnetic pickup that directly screws in 
place of the Bosch  points.  Fully compatible with any coil.  There is 
no positioning requirement as with the Allison.
I suggest this:
    The change to make is with how you connect the advance/retard 
unit.  Don't use the retard side.  You might like disconnecting the 
advance side too.  If I  found the an engine ran better this way, then I 
would crimp the slots on the distributor breaker plate tight against the 
sliding section to make effectively a solid breaker plate.  Leave the 
vacuum lines and advance/retard unit in place to keep the emissions 
police happy.  You can plug the vacuum lines with a sheet metal screw at 
the manifold.  Less parasitic vacuum loss also means more power and 
quicker throttle response.
    Set the 40 degree total advance at 4500 rpm.  Do this with the 
advance unit disconnected, vacuum lines plugged.   That will insure the 
distributor is fully advanced.  This should be the same position as you 
would get if you position the engine and distributor at #1 top dead 
center with the engine not running.  Then you can measure the timing as 
RPMs drop to find the point where full advance begins.  Partial curve 
timing is unreliable because destributors wear and advance springs 
stretch.  A stretched out spring brings on the advance sooner than new 
stiff ones.
    If you can get the Mallory coil, its hotter than anything else. 
Once I learned about NGK wires I stopped looking for anything else.  As 
you might have found with the Japanese cars, these wires last forever.  
With their low cost and the way NGK wires perform, high priced exotic 
wires were not worth trying.
    The 3 or 4 electrode RX7 NGK plugs were the best I found.  I 
plugged the wires directly to the plugs, not using the factory plug 
resistors.  The 6 heat range was best, unless you ran 10:1 compressions 
like on the 2002 tii.  Curious how BMW and many other manufacturers now 
use 4 electrode plugs as standard equipment.
Good luck,

Barry


Gregory Bradbury wrote:


> Hi Jerry (guess it's your name, you didn't sign your message).
>
> Thanks for the tips.  I was considering a Crane/Allison system, as 
> they make the pickup bits specifically for a BMW/Bosch 6 cyl 
> distributor.  Yes I did consider the advance / retard curve 
> situation.  I terribly boring one is a US E12 530i.  However Euro 
> distributors (I live in Switzerland and the car was built at BMW South 
> Africa) had / have more "interesting" curves.
>
> This specific Bosch dist is 0.2.237.302.010, used on Euro 525, 630, 
> 728 & 730 cars with EI.  The cars had the Solex 4 bbl carb.  Timing is 
> to be set at 22 degrees BTDC at 1500 rpm (525) or 1700 rpm (630, 728 & 
> 730).  Final advance is 40 degrees (+/- 3) at 3700 and 38 degrees (+/- 
> 3) for the 630, 728, 730.  Believe this is rather close to E3 / E9 
> territory.
>
> The vacuum advance is 12-16 degrees and retard 10-14.  Has vaccum 
> ports for both.
>
> Taking your advice SERIOUSLY, one should:
>
> a) Have a good curve:  My dist should do this, but would like your 
> advice.
> b) Have a hot spark.  I can upgrade to a hotter Bosch or Allison coil 
> to get this with either my points set-up, EI upgrade or aftermarket 
> upgrade.
> c) Burn better (RX-7 type plugs are a good idea.  Normal heat range 
> should be 6 for older 9 or 9.3:1 engines, good idea.)  Any idea how 
> well they would work with a factory EI system with or without a hotter 
> coil?
> d) Better wires.  Factory EI wires are good, I ALWAYS was a fan of NGK 
> wires and put them on any of the Jap cars I owned.  How about using 
> Magnacore or other wire alternatives?
>
> The other considerations are that:
>
> a) Switzerland has serious pollution tests (annual for non-cat cars) 
> and it's a more serious that California.  They look at CO, HC and 
> smoke.  No jokes here !!
>
> b) I have plans for vintage racing, so a factory looking system has an 
> advantage.  I don't believe they would allow an aftermarket system.
>
> Your thoughts and ideas are valuable, would appreciate more of your 
> comments.
>
> Best regards,
>
> Greg
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