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 Setting base timing 
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Joined: Sun May 12, 2013 5:21 am
Posts: 332
Location: Michigan
Ok I've read this n that and always tried to give it what it wants, but I still try to follow a baseline. For example if a cam says it would like 14-16 I set it there, but when it wants 20+???

So what steps would you take to find ideal base timing for a combo?

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Thu Jul 14, 2016 3:15 pm
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Joined: Fri Feb 08, 2013 5:50 pm
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Usually as much as the engine and fuel will tolerate. Engines with milder cams won't need as much, high idle vacuum improves vaporization at low speeds so fuel is distributed more evenly and burns quicker. Large cams with lower vacuum need more initial as the fuel burns slower.


Thu Jul 14, 2016 6:30 pm
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Joined: Sun May 12, 2013 5:21 am
Posts: 332
Location: Michigan
I can put it up to 40 initial and the vac keeps going up, can't go higher cause the vac can hits and I can't see why I'd need even full 36 locked out timing with my cam.

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Thu Jul 14, 2016 6:47 pm
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Joined: Sun May 12, 2013 5:21 am
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Location: Michigan
Forgot to mention it starts/fires the same at 14 or 40 initial and it's low comp. I've always thought you need some curve but trying to keep an open mind.

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Mon Jul 18, 2016 4:37 pm
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You can need 40 and sometimes over WITH the vacuum advance hooked up, maybe 36 at full load once RPM is up high enough. When idle vacuum is low because of a large cam that is when it needs the most timing, to have time to burn the fuel well. When converter stall is high enough you can usually lock timing and have enough to run decent, but not to say it might like more. M timing curve adds 3 degrees under 4000 RPM, as stall speed on the converter is high enough that it doesn't load it hard in that RPM range. As it passes that point it pulls 3 degrees, back to what it likes at WOT. Makes idle and light throttle cleaner, like having a vacuum advance.


Tue Jul 19, 2016 2:02 pm
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Joined: Sun May 12, 2013 5:21 am
Posts: 332
Location: Michigan
Car likes 38 total, but I'm not sure the marks are 100% accurate on this engine, so I'll give it what it wants for total. This dist has vac advance(ported source & still unhooked for all readings of course) because it's a street car. I ordered the FBO 10 & 14 deg msd bushings to try since it's set at max possible initial atm with msd bushings. I know Tuner likes to heat n bend the weights but I'll just screw them up and I'm not revving super high.

I was just reading that low low comp like a lot of initial so I'll try those FBO ones to compare to locked.

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Tue Jul 19, 2016 9:14 pm
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