Greetings to all, what a great forum! I own a 1974 280s w116, that was imported from South Africa. The distrubutor has two vacuum ports, with vacuum lines running to the carby, straight and does not go throught any solenoids or any thing.

Viewed from the front of the engine, the top vacuum port on the dizzy runs to the right hand side of the carby, where there is two ports on the carby, one for the idlespeed acutator, and one for dizzy vacuum.

The lower port on the dizzy runs to the left hand side of the carby, does this setup sound correct?

This car has no emission control, a so called euro model, the ignition is a pionts and condenser setup, not tranzistorized at all. Points go to coil.

what is the appropriate ignition timing settings and dwell, futher i deduct that this engine's ignition is retarded at idle, hence the lower vacuum port on the dizzy, why is this ?

sorry for the long post!!

if it has two vac lines to the distributor it must have a later us smog style dizzy. iirc the second vac port actually retards the ignition at higher rpm to decrease emissions. i suspect you may have a us spec smog setup there.

i will go look at my old books to see what i can find.

i would try to find a non smog distributor for the car.

it sounds very similar to the setup that was on my 74 bmw bavaria. i spent many hours modifying that distributor to non smog specification. the car felt like it had a two liter motor when i started and a good running three liter (which it was) when i finished with it.

tom w

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[SIGPIC] Diesel loving autocrossing grandpa Architect. 08 Dodge 3/4 ton with Cummins & six speed; I have had about 35 benzes. I have a 39 Studebaker Coupe Express pickup in which I have had installed a 617 turbo and a five speed manual.[SIGPIC]

..I also have a 427 Cobra replica with an aluminum chassis.

ok my old chilton book shows four distributor numbers with three different specified advance and retard specifications.

i will need the dizzy number to tell anything. the numbers i have will be for us spec models too.

iirc the distributors from that era have a lot of interchanbibility. when i modified mine i took several different distributors including one from a 1960 mercedes 220s and from a vw beetle and mixed and matched advance weights and springs and vac advance pods to achieve a pre smog operating characteristic. i had to file the holes in the advance mechanism plate to allow the movement of the weights to be increased in order to increase the mechanical advance at max rpm.

it was a lot of bother but was well worth it.

the simplist thing would be to find a distributor with the correct specification and just swap it out.

tom w

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[SIGPIC] Diesel loving autocrossing grandpa Architect. 08 Dodge 3/4 ton with Cummins & six speed; I have had about 35 benzes. I have a 39 Studebaker Coupe Express pickup in which I have had installed a 617 turbo and a five speed manual.[SIGPIC]

..I also have a 427 Cobra replica with an aluminum chassis.

to run the the retard dizzy port to the intake manifold port.

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1970 280S M130 engine- good runner
1971 250 M130 engine- #2 rod bearing, gone
1971 280SE (blown engine,parts car)
1977 German 280S W116-only 33 years old