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Alright guys I need some opinions on this, so today I decided to check my plugs and saw that the timing mark on the plugs is low close to the threads and that i know it mean it’s to advanced so I go and check timing and it’s only on 10 degrees initial when I checked total timing my guess springs are to stiff because at 3000 it wouldn’t hit 36 total my question is am I running to much compression?
 

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Spark plugs don't "read" ignition timing. That is done with a strobe timing light clamped to plug wire number one with 12 volts at the battery - then aimed at the timing indicator strip near the harmonic balancer. That is, if you are running an older Gen 1 small block Chevy motor.


Similarly, compression is what it is. While it is true that high compression aggravates timing issues if timing is too high, I think of compression as an independent variable that an owner can't do much about short of rebuilding the engine for lower compression.


What year for the engine?


HEI distributor or old school vacuum advance?


Rick
 

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Spark plugs don't "read" ignition timing. That is done with a strobe timing light clamped to plug wire number one with 12 volts at the battery - then aimed at the timing indicator strip near the harmonic balancer. That is, if you are running an older Gen 1 small block Chevy motor.


Similarly, compression is what it is. While it is true that high compression aggravates timing issues if timing is too high, I think of compression as an independent variable that an owner can't do much about short of rebuilding the engine for lower compression.


What year for the engine?


HEI distributor or old school vacuum advance?


Rick
i understand how to read timing with timing gun but on the plug it will tell you if your timing is too advance or too retarted, on the spark plug ground strap there will be a line where its a different color and if it’s close to the threads it’s to advance causing detnonation and if it’s towards the tip it’s too retarted Someone will verify
 

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maybe you could clue us in where you gathered that interesting piece of information. We all have heard about reading plugs for to rich or lean, but that's a new one.
 

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maybe you could clue us in where you gathered that interesting piece of information. We all have heard about reading plugs for to rich or lean, but that's a new one.
What he said^^^ We are waiting...:popcornsmiley:
 

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That link is interesting in many respects but a little too subjective for me with regards to guessing engine timing. Why not reach for a stroboscopic timing light to eliminate timing guesswork?


Rick
 

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Reading Plugs

Like most of you, I have been working are cars since I was in high school back in the 60's and even in auto shop they never, ever mentioned having the ability to read engine timing from a spark plug. Fascinating but like someone said, a bit subjective. It's like the US Cavalry American Indian guide tracking down Geronimo. I think he went that way Kemosabe!
 

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When I was at Holley EFI School in Bowling Green KY the instructor touched on this lightly. He was one of the most knowledgeable instructors I have ever had. not only EFI but all aspects of engine tuning. Here is a clue for all you old school guys (of which I am one) THE WORLD IS NOT FLAT. To simply discard this information because "I never heard it before" is short sighted. When I took auto shop in high school they didn't even have advance wheels on timing lights. How do you think the old mechanics at tracks like Indianapolis were able to tell timing. This information came from "way back" and I for one am glad to learn it. Go out there and pull some plugs and read them for more than fat or lean.
 

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I know this is an old thread, but great info. Like most others, I had never heard of that before, but there must have been a way to figure that out before modern electronic technology eclipsed the old way.
 

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As an old school wrencher, I cut my teeth on a 265 cid SBC. While I did check the spark plug tips, it wasn't for timing. For ballpark timing, I used my ears. I'd get close based on how the motor cranked at start-up. (y)

Thanks for the article Vinny!
 

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I'm still trying to wrap my head around flip-flops. He starts talking about 1 plug, says the WOT is too fat, so needs to advance the total timing. But idle is good, so don't change idle timing. There's only 1 distributer. How you can change WOT timing by turning the distributer, yet not change idle timing is beyond me. On top of that, my cap is computer controlled. Set cap at 0° and plug the computer back in. Can't change a thing.

I'm old school in a lot of ways, nice to see that it's not totally a dead art, but I'll take an airgun and body lift over a tire iron and gm bumper jack any day of the week.
 

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In order to read plugs you have to shut the engine down while at high rpm. Most of us dont have access to a track or a place where we could do this..

Actually I think power timing a engine is the best way. Disconnect the vac advance and plug it. Then keep advancing the initial until some full throttle pinging is heard and back off. Do this all on regular gasoline with a 180 t stat.. Next try some premium and see how it runs. Go back to regular and try a 160 t stat. And see how that goes..

Its a lot of work but this is the correct way to get your motor to run at its optimal.. My 454 likes 21 initial with 14 mechanical all in by 2500... It also likes regular gas with a 160 t stat better then premium with a 180..In this heat I run 89 though.. It also does NOT like a vacuum advance.. I tried limiting it and moving it all around with nothing to show. It also sounds real tinny with a weird skip-smooth-stumble while idling in gear.. Every time I try to bring it on, I end up taking it back off in a hurry.. lol
 
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