Please Help Identify Distributer

needlevalve · needlevalve's Garage

Can anyone help me identify this distributer (935 or RSR?)

Bosch Part # B237490013

Other inscription reads:

1G 6 x 2 <----
Kat. C 2/13

Help Appreciated!

Thanks

RPMClassic · 05-15-2002, 07:31 AM

I called the Bosch hotline, checked factory literature and all my Bosch books. I think your "B" in the item # you write, might be an "8". I will continue to look and post a follow up if I find anything.

Jim

Early_S_Man · 05-15-2002, 11:48 AM

Matt,

Does that disributor have points ... if so, it would be much older than RSR or 935 vintage, because they used magnetic trigger, not points!

My '70-'72 Competition Parts Catalog focuses primarily on the racing Marelli distributor, and doesn't list a Bosch dual-plug distributor, or any spare parts for one!

pwd72s · 05-15-2002, 11:54 AM

This is totally off the wall, so please don't laugh...but 12 wires? Bosch? 917?????

emcon5 · emcon5's Garage

That thought crossed my mind too. How can you tell a distributer from a single plug 12 cylinder from a twin plug 6 cyl?

Also, are you sure it is a Porsche part? There have been a few 12 cyl cars over the years from other companies that probably (just guessing) use Bosch electricals. BMW comes immediately to mind.

Tom

edit, or was the 917 twin plug?

pwd72s · 05-15-2002, 12:19 PM

AUTOMOBILE QUARTERLY, Volume 9, no. 2, (I've had it for decades), shows longitudinal and cross section drawings of the 917 engine, as run in John Wyer's Gulf sponsored 917's. These drawings show one distributor, 12 wires. Also an engine pic as installed in the chassis: One distributor, 12 wires. Of course, no way to tell part numbers. This all from the fall/winter, 1970 issue of the magazine. Looking at the drawings with a magnifying glass, I see what I would describe as a hemi head, single plug, HUGE intake & exhaust valves for the space allowed. I'll put it this way, I sure wouldn't sell the distributor in the pic until I found out for sure what it is. So, needlevalve...where did you find this?

needlevalve · needlevalve's Garage

First off, thanks to all for your input. I may have discoverd some insight on this. The distributer came from a whole whack of parts which were acquired with an RSR clone project. I had assumed it was an RSR distributer but wasn't 100% certain. I listed it on ebay as such and received a reply from a fellow enthusiast who has both an RSR and a 935. He beleives it is from a 935 as it has two terminals. By his account the RSR's had just one. Both used the same cap and rotor. It can be used with an RSR application by crossing the A and D and B and A terminals. RSR's originally used a Marelli distr (as Warren mentioned) then went to the Bosch. Warren this ditributer does not have points as the earlier systems did. Not sure whether this may have been used on 917 applications.
All in all an intersting piece.

Thanks again!

lendaddy · 05-16-2002, 06:20 AM

It's probably worthless but I'll give ya $100 for it as a paperweight

Seriously though Andial would probably know they are the twin plug freaks, no?

Early_S_Man · 05-16-2002, 01:00 PM

If you really want to ID the dist. ... call Andial, as they probably have a few laying on their shelves!!!

OK ... since it is the magnetic trigger type, itis most likely the later 917/RSR type ... the only way to be sure would be to test it on a distributor machine and plot the advance curve. All 917's had dual plugs and used two of the 12-port distributors -- one at each end of the crank -- that were later used on the 2.8 RSR and 3.0 RSR ... one for each bank of the engine, since each of the distributors connects up to two coils and handles 2 plugs for 6 cylinders, hence the designation on the distributor body: '6 x 2!' The way you would test which terminal to use, and this is the same for a 917, RSR, or RSR clone ... is to use a multimeter, each trigger coil is separate, and feeds a single CDI-unit of the 6-pin 911SC variety! The trigger coils are probably 600 Ohms, just like the later SC and Turbo distributors!

The distributor is quite usable on a streetable, normally-aspirated dual-plug engine ... all you need is two CDI-units and two coils!

Early_S_Man · 05-22-2002, 02:45 PM

August 2002 issue of Excellence has an article about Jo Siffert's 1971 Can Am car that has been restored ... and a pic on p. 78 shows a good view of the rear distributor, and it looks EXACTLY like your 'mystery' object!

needlevalve · needlevalve's Garage

Nice Warren, do you mean Aug 2001? I will begin digging through the archives to find that issue.

Early_S_Man · 05-22-2002, 04:14 PM

No, Matt, my August 2002 issue just arrived today, and for once ... nobody had posted about it days before I got my copy!!!

Superman · 05-22-2002, 05:56 PM

Well, now I know what to expect when my copy arrives. Hey, this is a fascinating discussion. So, a 917 engine would NOT look like a big spider. Instead, the ignition wires would probably run just straight down the edges of the heads. Clean. Pretty, I bet. Pretty effective too, apparently.

needlevalve · needlevalve's Garage

Well, I have verified this part. After speaking with Pete from Andial, we have established that this distributer is a 935 part. The difference between the 935 and RSR dual point distr. being that the 935 has no centrifugal advance where the RSR does. Thanks for all the input!

Wayne 962 · Wayne 962's Garage

Geez, you took my thunder! I knew that! The real check is for the centrifugal advance mechanism. The 935 had none, because it ran in a very narrow RPM band and didn't really need one...

-Wayne