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-   -   Pertronix into a Marelli S145C anyone? (https://www.alfabb.com/bb/forums/engine-management/676698-pertronix-into-marelli-s145c-anyone.html)

Anth73 03-14-2019 03:57 AM

Pertronix into a Marelli S145C anyone?
 
1 Attachment(s)
Test fitted the Pertronix Ignitor 1 and Flamethrower coil purchased from Classic Alfa into the Marelli S145C distributor on my 1974 2000 GTV. Prior to replacing the points with the Pertronix Ignitor I fitted a new cap and rotor, new leads and new spark plugs, set the timing at max advance at 4600rpm and made sure the mixture screws, carburettor balance and idle setting were as good as I could get them. The engine started after a few cranks from cold without misfire and revved well.

I fitted the Pertronix Ignitor without taking the distributor out using the fitting guide for the large distribution cam setting, removed the ballast resistor and fitted the Flamethrower coil. I also checked the static timing following the recommended procedure and thought all would be good as the test light on the negative coil terminal read 12.8V.

Unfortunately the engine cranks and cranks but I donít get ignition. Iím getting what looks like an OK spark and double checked the rotor position and static timing and all looks in order.

Reading the FAQs and online forums, people have made mention of a distributor ground wire but not specifically for the Marelli distributor. Attached is the points and condenser setup I removed. Wondering if Iíve overlooked something? Has anyone else fitted a Pertronix Ignitor 1 to this model Marelli distributor?

gprocket 03-14-2019 05:04 AM

2303 Attachment(s)
I've done the conversion a number of time without a problem. The fact that you have spark would suggest to me that it's a timing issue. I'd start advancing the dizzy (turning CCW) in small increments and see what happens. Double check the firing order 1-3-4-2.

No need for a separate ground on the dizzy. Red wire to the + pole on the coil, black wire to the - pole.

Alfajay 03-14-2019 08:26 AM

Quote:

Originally Posted by Anth73 (Post 8387608)
I fitted the Pertronix Ignitor without taking the distributor out using the fitting guide for the large distribution cam setting,

As gprocket wrote, your problem is likely the timing. The Pertronix doesn't necessarily fire the coil at the exact point that the old points did - some re-timing of the distributor is necessary.

Quote:

I’m getting what looks like an OK spark and double checked the rotor position and static timing
How did you check the static timing? With my electronic distributors, I rotate them CCW until a timing light on the #1 wire fires. You need to turn them fairly fast to get the ignition to fire, so you end up going past the firing point - need to judge how far back to turn it CW to return to the point where it fired.

Anth73 03-15-2019 01:53 AM

I will try advancing the timing as suggested. I set the static timing by firstly lining up the F mark on the crank pulley to the indicator, checking piston #1 was at the top with valves closed (peering down the spark plug hole) and the rotor pointing to #1 spark plug lead. I then rotated the dizzy anticlockwise slightly and connected my test light to the negative coil terminal. I then rotated the dizzy clockwise until I got a 12V reading on the timing light.

Anth73 03-22-2019 10:46 PM

Thanks for everyone’s help. Tweaking the static timing by advancing the dizzy a bit at a time and checking it with my test light did the trick.


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