how to set timing - mallory mechanical advance on '74 1.8 Options

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I need to set ignition timing on a '74 1.8 that has a mallory dual-points mech adv distributor. Model # of mallory distrib is 2354101, in case it matters to someone.

Anybody have tips on how to set timing on this setup, assuming the rest of the engine is basically stock?

Prior to any attempts to set timing, I plan to replace both sets of points, condenser, and adjust the dwell.

Thanks in advance for any help

[MarkV]

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Yes in this example 12 initial timing + 16 advance = 28 degrees total advance

My T4 engine is set at 8 degrees and is programed for 20 degrees advance, so 8 + 20 = 28 total advance.
Mine is a crankfire ignition, but I've also done this with a mallory using the 20 key.

To me 12 degrees initial advance is too much, I aim for 8 degrees and 900rpm idle. 10 is about the most I ever use.
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Interesting. Seems like when I tried setting the initial that low I had a problem with an off idle bog. That was using a Bosch 050 distributor. Don't know if I ever tried it with the Mallory. What is the issue with running too much initial advance?

[Mark Henry]

Interesting. Seems like when I tried setting the initial that low I had a problem with an off idle bog. That was using a Bosch 050 distributor. Don't know if I ever tried it with the Mallory. What is the issue with running too much initial advance?

Problem with answering this is I'd have to write a novel (IMG:style_emoticons/default/biggrin.gif)

I aim for 8 degrees. 900rpm and the carb idle screws out 1-1/2 turns. This with a warm engine, the linkage/throttle plate stop barely touching the stop screw and one linkage arm disconnected. Likely it will run a bit slow, so turning the linkage/throttle plate stop screw a 1/4 to 1/2 turn gets you to an acceptable idle.
This is the point that you sync your carbs and when you reattach the arm nothing should change. After this a quality linkage, opening at exactly the same rate, is what keeps it in sync.

Then comes jetting, but if your jetting changes you have to start again from step one.

As always when tuning a carbs this is assuming that you engine is in good mechanical condition. Beyond this point there's often an issue with the secondary jetting, dirt in jet/fuel, way too aggressive cam or another mechanical issue.
The idle screws out more than 2 turns and you are running lean at idle. Running more than say 1200 rpm at idle and you are off the idle circuit.

I'm no longer a fan of 009 and 050 dizzy's, they always seem to have or create a flat spot. I run a fairly aggressive WEB 163/86b cam (my favorite big T4 cam, 2270cc+) and have had no issues, other than a slightly lumpy, 900rpm idle using a mallory.