Setting Timing

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Wdschell

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Good evening everyone,

I have been trying to tune my timing for a while now and have read just about every thread on timing there is on here or hotrod.com etc and I am still confused.

My question is when setting my total timing, do I set the RPM that I want the mechanical advance to be all in at and then tune it to 34-36 degrees from that? Or do I just set it to 34-36 at when the mechanical advance stops coming in?

I have a cheap amazon distributor that i have replaced the coil in with a standard GM coil since the one it came with went out
here is the link. http://a.co/fHmomfo It says it has total 32 degrees timing.

My Pickup seems to drive around fine until I am on the highway cruising at 65 and try to accelerate or go up hill and then I get some ping. Have a 327 with mild cam and current initial timing setting is 14 degrees btdc.
 

Wdschell

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Also my vacuum advance is currently connected to the ported spark option on my edelbrock 1406
 

74 Shortbed

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Your total should be all in by 3000 or less(2500-2700 if the engine can handle it)that's acomplished with different springs(trial and error)and with vacuum disconnected, also vacuum should be hooked up to full vacuum port, ported is a smog thing..
 

Wdschell

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Ok I am all in around 3k and about 34 degrees right now. Just wanted to make sure I was doing it right. I will move my vacuum advanve over to full vacuum too.

Will I need to readjust mixture when I do that?
 

74 Shortbed

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Adjust mixture and idle, with full vacuum initial timing will be advanced around 15* at idle so it will idle higher, it will have a lot nicer idle after adjusting it..
 

Wdschell

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So it will be 14 initial plus 15 from the vacuum. So 30* total at idle.
 

74 Shortbed

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Yep, that's if you have a 15* vacuum can, after setting total look at the initial, then hook up the vacuum and look at the initial and see how many degrees it advanced, that will tell you how many degrees is in the can, then add that to the total and that's what you'll have when you're cruising, should be around 50-52*..
 

Wdschell

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I believe the vacuum can is adjustable. So I'll check my total again tomorrow then move the advance over to full manifold and adjust everything from there. I appreciate the help I have been fighting this for about two weeks before I found the coil was failing. What kind of milage should I expect?
 

74 Shortbed

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Just remember that the vacuum and mechanical are two separate deals, and the mechanical has to be done first then you can play with the vacuum.
 

Wdschell

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Just checked this morning and my initial timing is 14* BTDC, with mechanical 34* all in at 3k and with the vacuum advance hooked up initial is about 30-31* so that puts my total about 52-53.
 

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If you still have pinging, lower the initial a couple of degrees or try some better gas.
 

Wdschell

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I am running 91 octane right now. That being said it is still California gas...I drove around on the highway just now and was getting a little bit of ping so I moved the initial to 12*. It only ever happens to me on the highway can't replicate it otherwise
 

Wdschell

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Looks like my vacuum can is adding about 18* at idle. Should I adjust that down a bit?
 

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Depends what your total is, if you have it set at 34-36 that means 52-54 at cruise, that's ok if your engine can take it only way to find out is try it, take your allen with you go out on the road and play with it, if it rattles back it a down a bit at a time until it stops, I'd back down the vacuum before the total first, if it won't work then back off the total a tad.
 

Wdschell

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It didn't like the 52 at cruise I had some rattle for sure. When I adjust the can does turning it clockwise add or subtract advance?
 

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