what do these spark plugs indicate about running condition?

Craig Nedrow said:

Auroragirl, if you are like me, not made with money. Set initial timing to 8 degrees BTDC (before top dead center) start up and warm engine, hopefully you have a timing light. Depending on the compression, you should be able to run between 32, and 36 degrees advance, all in around 24-3000 rpm. If it is a stock cam, idle around 700 or so, when you shot it off, if it continues to run, (diesel) retard the timing a few degrees. I run a low rpm load, punch it and listen for detonation, and continues advancing until it detonates, then back off a few degrees. This works with the gas you run. I to want a proflow on the new 454 I just installed, but $$$$.

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SquareRoot said:

I've learned from decades of experience when it comes to going down the rabbit hole. You're going to end up in the bottom eventually. It's less frustrating and cheaper not to beat around the bush. Close eyes, hold breath and dive in! Once the pain subsides your at the finish line.

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AuroraGirl said:

Well what i was asking earlier is can I trust the timing marks on the crankshaft? I have no idea if its shifted like it does for others over time.

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Bextreme04 said:

You can either mechanically verify the mark, or you can tune by vacuum. To mechanically verify, install a TDC tool or a tight fitting post/screwdriver in the #1 spark plug hole. Turn the motor over by hand either clockwise or counter clockwise until it hits the post. Put a mark on the harmonic balancer where it lines up with the 0 timing mark on the timing cover. Then rotate the motor the other direction(by hand) until it again hits the post and stops. Place another mark on the balancer where it lines up with "0". Halfway in between those two marks will be the actual #1 TDC.

Alternatively, you can just hook up a vacuum gauge to manifold vacuum and just adjust timing until you have max vacuum. That should put you right around 8-12 initial. If peak vacuum seams lower than it should, you are most likely running rich and need to adjust your idle mixture and idle rpm as well.

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