BR18 distributor rebuild service?

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Jacques Lefriant
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Re: BR18 distributor rebuild service?

#16 Post by Jacques Lefriant »

Hi
personally I prefer investing in say a 123 distributor or the Pertronix Ignitor III rather than the cosmetics. Even Ab had concerns that the cam lobes could not be rectified and no amount of effort would produce commensurate results.
j
 

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Neil Bardsley
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Re: BR18 distributor rebuild service?

#17 Post by Neil Bardsley »

I have a 123 in my 912 and 022, rebuilt by Bruce Smith, in my 356 both work very well but no need to check the points on my 912

Erik Thomas
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Re: BR18 distributor rebuild service?

#18 Post by Erik Thomas »

Glenn Ring is fast and reliable. I have 3 of his distributors in my fleet..

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Chip Flor
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Re: BR18 distributor rebuild service?

#19 Post by Chip Flor »

You have to be careful because some rebuilders change the advance curve from stock.
For example one of the builders mentioned is a believer of the Stock advance 35 degrees total advance. Several other respected mechanics and an oil company gas expert believes this is the way to go.
Another has his own version of what he believes is a "Modern Gas" advance with no more than 32 degrees total advance.
Many experts believe stock advance will lead to detonation and destroy your motor.

So you really need to know what advance curve you want to run.
Don't go blind into a rebuild or purchase without securing your position of what you believe is the right total advance for your engine.
Last edited by Chip Flor on Mon Jul 01, 2019 1:32 pm, edited 1 time in total.
 

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Neil Bardsley
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Re: BR18 distributor rebuild service?

#20 Post by Neil Bardsley »

Chip I would be interested to understand what you mean because the adv on a normal 18/022 is 30 degrees. Most set there max adv and therefore the static is that minus 30. Therefore a max adv of 32/36 is achievable with stock distributors.

If Bruce rebuilds your distributor, or am sure another, you get a graph of the adv curve on your distribution so you know what it does.

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Chip Flor
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Re: BR18 distributor rebuild service?

#21 Post by Chip Flor »

5 degrees static timing plus 30 degrees distributor advance (+ or minus 2 degrees) equals 35 degrees total advance.

Here is an example of a different curve. A 050 distributor for example has a completely different curve with an advance of 27 degrees. Therefore with 5 degrees of static timing (plus 27 degrees of distributor advance) you get 32 degrees total advance.

From my first hand experience I purchased a rebuilt/restored BR18 and it came with an advance curve that topped out at 27 degrees not 30 (as is expected from stock from a BR18 or 022). I ended up sending it back to be recurved. Regrettably it could not be turned back to the stock 30 degrees advance spec.
Be careful, not all builders advance to stock specs of 30 degrees because they believe the stock advance will lead to detonation (with a total advance of 35/36 degrees).
Others believe this is hogwash... You need to know what your bargaining for.
 

Mike Horton
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Re: BR18 distributor rebuild service?

#22 Post by Mike Horton »

Chip, all, the real difference, in the timing we can safely run now, is due to the difference in today's fuels, when compared to what was available when these cars, & engines were new. As well, there is a real difference, in changes made in each engine build, compared to the originals.

C.J., Vic others?
Mike

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Chip Flor
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Re: BR18 distributor rebuild service?

#23 Post by Chip Flor »

Glenn Ring runs stock 30 degree advance in his BR18's. Jack Staggs has no problem running 35 degrees total advance in his customers (356) cars.

On page 21 of the A owners manual the factory suggests 86 octane ROZ. (RON)

Octane back then is rated differently than today. Also European octane ratings are different than in the US. In the US we rate our octane R (RON) + M (MON) /2.

R + M/ 2 is considered an anti knock index. One can see that our US octane rating when compared to the European index is much more conservative.
Here is an example: "EuroSuper" or "EuroPremium" or "Regular unleaded" in Europe, "SP95" in France, "Super 95" in Belgium: specs out to 95 (RON) and 85–86(MON) Octane rating.
To convert this to our US Octane rating you get 90–91 (RON + MON/2).

[95 (European octane index) = 90/91 (USA octane index)]

In other words, the European spec 86 ROZ(RON) as suggested by the factory is a lower octane rating than what is sold in our 87 (R+M/2) USA octane pumps today.

Having said that, a US 91 Octane (Supreme) gas rating in our cars is even more conservative to ever having detonation taking place in our 9 to one compression 356's.
You can conservatively see that you are in no way creeping into no-mans land of detonation with the stock 35 degrees total advance set up running premium gas in your 356.

Unless they have changed the specific gravity weight of gasoline (which they haven't) you have nothing to worry about.


This whole MODERN FUELS of Today argument does not wash with me. Regardless, everyone is entitled to their opinion and can choose for themselves.
For the record, I run 34 degrees of total advance in my Maestro built '56 engine. I removed the 050 distributor (his choice back in 2003) and it runs noticeably better with the stock spec BR18 that I have replaced it with.
Last edited by Chip Flor on Sat Jul 13, 2019 12:49 am, edited 2 times in total.
 

Mike Horton
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Re: BR18 distributor rebuild service?

#24 Post by Mike Horton »

Good homework, Chip, and I agree with your presentation.

Find, however, and read all of David Jones writings on the 10% ethanol fuels, and needed changes in the higher compression ratio engines, for success. I did, and learned a lot. I rejetted my stock '68, US smog tuned 912 richer, and got my high oil temps back under control, and fuel mileage back to normal, when commuting in this West TX hot summer weather, about 18,000 miles ago. I run about 32*, at 3200 rpm, in my 022, and the 91 octane 10% ethanol fuels, when on the road away from home. My commute was from 3300', to 3700' elevation.

Your car, your choice, my 356 Friend,
Last edited by Mike Horton on Mon Jul 01, 2019 3:19 pm, edited 1 time in total.
Mike

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Chip Flor
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Re: BR18 distributor rebuild service?

#25 Post by Chip Flor »

David Jones is a genius...
We have exchanged emails concerning this subject. He is a great person.
Being an X-oil company gasoline expert and X-SCCA Formula Vee racer, he too runs stock 35 degrees total advance timing in his 356s.

I too was wondering with the advent of alcohol if re-jetting the carbs (i.e. fattening of the jets) would be advantageous.
How much more did you fatten your jets? I would imagine the elevation changes would have fattened them by default (with less barometric air pressure i.e. less denser air).
That makes a whole lot more sense regarding backing off on the timing (plus your 912 starts out with 3 not 5 degrees static timing stock).

Inquiring minds?
-chip
Last edited by Chip Flor on Mon Jul 01, 2019 3:36 pm, edited 1 time in total.
 

Mike Horton
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Re: BR18 distributor rebuild service?

#26 Post by Mike Horton »

Yes, Chip, my 022, functionally the same as a BR18, does offer the best performance, in my opinion, I've not tried any of the electronic versions, but most of which I've read, use the 356 curves, and in my '68 912, jetted lean, to pass the then new "smog" tests, has Solex split shafts, which came with 55 idle fuel jets, and 125 main fuel jets ('69 specs), and I changed the idle fuel jets to the earlier pre smog solid shaft 57.5s, and installed 127 main fuel jets, in my tired old 1582cc original engine.

These days, each engine may be different from original, so some research may be needed. IIRC, Ron LaDow, at Pre-Mat, says the 356 C specs, for Zenith equipped engines, will handle the big bore 1720 conversions, and the 912 Solexes, at sea level, may need 130, or richer mains. The earliest S90s came with 60 idle fuel jets, the Rock catcher air "filters", and way small main fuel jets. The Solexes through their life, came with a variety of jets, so be informed.

My nearly ready spare engine, will be a big bore, just under 9:1 S90, and it will be interesting how differently it will need to be tuned.

Thanks for your post, we all help each other, with each lesson learned, going forward...,
Mike

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Chip Flor
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Re: BR18 distributor rebuild service?

#27 Post by Chip Flor »

Well said Mike
thanks for sharing your specs.
 

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