Here's one for ya...

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dart_68

dart_68

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Was checking my ignition to see what my initial and total advance was for mechanical advance alone and with with vacuum. (360 LA)

Idling @ 800 my initial was 16* with vacuum disconnected. When I slowly began to raise the RPM the timing went down, yes down, to 10*. Then as the RPM continued up it got to a total of 20* at about 3500. I thought I was seeing things so I kept checking it and it did the same thing every time. At least that was consistent.

When I added the vacuum the total was over 40* at about 4000 but the RPM had a big problem with going higher as the ignition would breakup. Could hear it, see it with the timing light, and shook the whole car pretty bad.

Not sure what's going on but I've been fighting gremlins on this thing for a while now and have thrown in the towel on this ignition system. The gentleman I bought it from said he had problems too and eventually gave up. I thought I could find the problem(s) with enough time but enough is enough...I'm done. System is a stock Mopar electronic distributor triggering an 8 pin HEI module and coil. I decided on a Petronix III distributor as the module is internal and has a built in rev limiter. Had to get a coil too to match the module.

Not really asking any question here but if you have any input on what was going on I'd love to hear it.

Thanks!
 
Well, you would seem to have too much initial timing. 10º at 800rpm might have been a better starting point. That would put you at 34º at 4000rpm which would be reasonable as a max advance. I would have just retarded the initial timing to 10º and see how that worked.
 
Some of those HEI modules had retard functions in them when grounding a certain pin. Some pins could also be used for a start retard if I remember correctly. Sounds like you made a good decision to nix the whole setup and start fresh.
 
40 degrees at 4000 with the vacuum can hooked up to ported and no load is not “too much”. It sounds like a good recipe for fuel mileage to me.
 
The Pertronix distributors are really tall. You'll need to run angled plug wire boots on the cap otherwise you'll hit the wiper motor body. Even then, the boot will be very close to the wiper motor. You might need to index the oil pump drive gear over 1 tooth to position the distributor cap in the best location.
 
Why not use a Mopar box with the distributor you have?

Pertronix has a GM HEI Module with a rev limiter too.
 
With the Timing going down when you bring up rpm- are you connected to the proper port on the carb?
 
Syleng1 said:
With the Timing going down when you bring up rpm- are you connected to the proper port on the carb?
Click to expand...
^^THIS^^ is where I'd start. Check timing at idle, remove hose, see if timing changes
 
I had a friend who had a 383 distributor in a 318 once. Because it is made to turn the opposite direct, it was retarding timing with more RPM. It's a close enough fit to bolt in and run.....and not run well like you describe.
 
Use the 4 pin module & your problems will go away....
Pertronix modules have a checkered reputation. Cannot go wrong with the stock GM 4 pin module for your combo; coil should work ok with it if it is an E-core.
If you want a little more 'oomph' from the ign system, use the MSD 83647 module; has built in rev limiter, switches 7.5 amps v stock 5.5 amps.
 
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