Marelli twin plug advance map

BURN-BROS · 06:28 AM

I mapped the advance of a Marelli that was off of a 2.8 rsr. I got a linear rise from 600 to 4000 rpm (distributor). The total advance was 14 degrees. Does anybody have some other numbers that I could compare to? Thanks in advance(no pun intended).

Steve@Rennsport · 06-13-2004, 11:25 PM

Hi:

Thats a decent curve for a moderately high-compression, twin-plug motor.

These ran at 26-28 deg total at 4000 RPM.

BURN-BROS · 06-14-2004, 06:42 AM

Thanks Steve, you are a wealth of information. Aaron

Steve@Rennsport · 06-16-2004, 06:32 PM

Hi Aaron:

LOL,...I have the full map for the Marelli 2.8 RSR distributor as I raced with one for several years.

The Bosch RSR ones were similar.

BURN-BROS · 06-17-2004, 06:06 AM

Steve, I have been working on a rotor for the Marelli for some time now. I changed the design to use a $60.00 jaguar 12 cylinder cap. It should save at least $350.00 for a tune up. I will be casting in a couple of weeks.Do you think there will be interest?

Steve@Rennsport · 06-17-2004, 07:41 PM

Yessir, I think so.

I'd like to see your finished product!

Henry Schmidt · Henry Schmidt's Garage

Anyone who can come up with a single cap and rotor for a twin plug application that is under $500 is on to something. I would be pleased to see and test anything like you describe. Let me know when you've got a product in hand.
BTW: this guy needs a cap, who's got one? Thanks

DIABLO 914_6 · DIABLO 914_6's Garage

I will let everyone know soon. I will be using copper for the metal parts(unless anyone has any better suggestions). Aaron

BURN-BROS · 06-18-2004, 12:21 PM

Woops, Logged on my dad's computer. Btw if anyone can guess at a volume that would be great. I know it won't be much but it would help to get a feel on how long my ass will hang out.

nein14-6 · 06-18-2004, 12:47 PM

Alright guys could you all clarify something for me? What companies made twin-plug distributors for Porsche? My 67 parts car came with a single plug distributor with an twin-plug adapter piece on it, the cap is Marelli(black).

nein14-6 · 06-18-2004, 12:48 PM

Also, why hasn’t someone tried to reproduce these? Trademark infringements?

Henry Schmidt · Henry Schmidt's Garage

Magneti Marelli make distributers for early style engines (906, 911R) and Bosch made them for the late engines (2.5, 2.8 RSR. 917, 935,3.0 RSR) The Picture above is a bosch 3.0 RSR. The picture below is a Bosch from a 917. I have modified it to fit a 2.8/ 3.0 RSR style engine.

Henry Schmidt · Henry Schmidt's Garage

Quote:

Originally posted by nein14-6
Also, why hasn’t someone tried to reproduce these? Trademark infringements?

Cost is the problem. If you could make a 100k of them they would be cheap. Andial makes the rotors and next year they will make the caps.

BURN-BROS · 06:22 AM

The question is what is an appropriate price for a distributor if reproduced?

I got quoted for injection molding the rotors and The price for tooling outways going that direction. There is an article in the excellence out right now about the guy who is making rotors for andial(showing off his weird brown 930 with mag rsr centerlock wheels.

Henry Schmidt · Henry Schmidt's Garage

Quote:

Originally posted by BURN-BROS
The question is what is an appropriate price for a distributor if reproduced?

I don't know what is appropriate but I would be willing to spend $500 all day long for a (non Bosch) cap and rotor that had the same function and feel.

Steve@Rennsport · 04:58 PM

Henry;

FWIW,...2.8 RSR's had Marelli's, not the breakerless Bosch ones. On 911's, those were first used on the 3.0RSR. I raced both for years,.......

I used to make custom RSR distributors that accepted Bosch RSR caps & rotors. These were racing units without advance mechanisms, but streetable with programmable MSD retard boxes and CD's. The issue was always getting caps & rotors. If Andial gets caps, then I might resume production.

BURN-BROS · 06-27-2004, 02:32 PM

Update! Got the bits and pieces I needed to start casting. Silver soldered some of those bits and did a test to see if the mold release would work. The mold release was not right so I need to buy some tomorrow. Let you guys know.

smdubovsky · 06-28-2004, 04:44 AM

Aaron/Steve,
You mention 14 deg advance at "600 to 4000 rpm (distributor)".

That means the engine would advance from 12-14deg to 26-28deg from 1200-8000rpm? 4000rpm seems like an engine rpm, but you specifically mention "distributor" right after rpm.

Tnx,
SMD

BURN-BROS · 06-28-2004, 06:13 AM

I got this old distributor tester that I am still trying to learn all the ins and outs. I believe that it is engine rpm and the books that I have bought on the subject suggest full advance around 3000 to 4000 rpm(depending on engine and application). Steve and Henrey have true experience with it. Hopefully they elaborate.

BURN-BROS · 07-16-2004, 04:11 PM

I cast the first part last weekend. The supplier gave me inappropriate matl. to cast with(brittle). I have some other formulas to try that are more sturdy this weekend. I have a client that does injection molding inhouse, I will likely trade out so I can have access to some equipment/knowledge. If I pull a decent part I will post it. Aaron