br9 or br18

[Walter Reich]

I have a 356 C car with a 1960 super Engine which has a BR9 distributor. It calls for BR18. What is the difference between the br9 and the br18 and does ether the br9 or br18 improve the out put of the super. The super engine is stock. I am going to keep it stock. Thanks to the 356 experts out there. I am learning all the time.
Walter Aurora, Colorado

[Bruce Smith]

Walter -

The spec. advance curves for the BR9 and BR18 are the same. Here's the breakdown of cars they were installed in:

VJ 4 BR9 (or BR9): 356A in 1956 and 1957
VJ 4 BR 18 (or BR18): 356A from late 1957 and all 356B engines
0 231 129 022 (or 022): 356C, SC and 912 through 1967

You'll find more information at: http://sparkingplugs.com/4.html

- Bruce

[Walter Reich]

ADAM JOHNSON in reply to my br9 & br18 Please e-mail me direct wr6151@q.com

[Dave Erickson]

Walter -

The spec. advance curves for the BR9 and BR18 are the same. Here's the breakdown of cars they were installed in:

VJ 4 BR9 (or BR9): 356A in 1956 and 1957
VJ 4 BR 18 (or BR18): 356A from late 1957 and all 356B engines
0 231 129 022 (or 022): 356C, SC and 912 through 1967

You'll find more information at: http://sparkingplugs.com/4.html

- Bruce

Hi Bruce,
the Porsche Spec book has some relevant information. i.e. the advance curve for BR9 and BR18 have different specs (advance range, start of advance, 5deg, 10deg and max advance are all slightly different). Also BR18 was used on C and SC, at least initially. My 64 SC (built 3/64) has a BR18 distributor in it.

-Dave

[Bruce Smith]

Hi Dave,

I agree with you about the Cs. I think Bosch started their ‘new’ numbering scheme sometime around January 1964. Of all the 022s I’ve seen, the earliest date has been 1/64, which would be consistent. Since ‘64Cs were started around July ’63 (#22 is July ’63), a Bosch BR18 would have been installed in the earliest and probably until inventory was used up.

Regarding the BR9, BR18, and 022, the internal parts vary somewhat with some differences in stamped numbers. Here is a list of what I’ve gathered for all three.

BR9: arms-12, base-607, advance-460
BR18: arms-27Z, base-526, advance-399
022: arms-27Z, base-603, advance-399

The BR18 and 022s have the same advance curve, the base makes no difference and the springs are the same. You might expect that the BR9 would be different, and references might suggest that. But when rebuilt with original springs, their advance curves fall within the spec. band for the BR18/022. There seems to be a bit more variation than with the newer ones, but the onset, increase, and end point of the advance curve are basically what you’d get for a BR18. And maybe the differences you mention are within the upper/lower limits. This is what I've seen, others may know differently. I’ll post some results when I get a bit more time.

Bruce