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feedback on timing marks with cylinder 1 at aTDC


lking240

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Hello all, I would be interested in feedback from the forum about how the timing marks are lining up on my 72 240. 

I found TDC for piston 1 and the pointer is aiming "below" the first mark, see pic.

My understanding is the lowest/first mark on the crank should line up with the pointer when cylinder 1 is TDC and 0 degree advance. i have a stock set-up and considering upgrading to electornic ignition module pertronix II. the distributor looks to be advanced about 1/2 way looking at the lines on the body of the distributor, but if the pointer is accurate then could it actually be retarded ~8 degrees?

thank you for any insights.

timing marks 1.png

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2 hours ago, lking240 said:

Hello all, I would be interested in feedback from the forum about how the timing marks are lining up on my 72 240. 

I found TDC for piston 1 and the pointer is aiming "below" the first mark, see pic.

How did you find TDC? 

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fashioned a vac/pressure gauge to put in cylinder 1 spark plug hole, remote start bumped it until the marks were close to the pointer, then hand turned the crank until the vac/pressure gauge went back and forth to home in on TDC, and then looked into cylinder 1 through spark plug hole and it was right there. Please tell me if I am missing something. Thanks for all the helpful replies.

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4 hours ago, siteunseen said:

image.png

Hey, isn't that backward?  The notches will move down as timing advances, so the zero notch should be the bottom one and you'll get 5 degrees per notch by the light as timing advances.

I tried to find a reference in the FSM but it says the zero is "to the left", and the picture shows a head-on view.  I'm sure those notches will "drop" by the light though as you rev the engine, as the single notch does on the 280.  So, he's only a few degrees off.

At close to TDC you can move quite a few degrees with almost no piston movement.

Edited by Zed Head
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The simple direct answer is "yes, your picture looks off by about 8 degrees".

Your damper might have slipped, or your method isn't precise.  A hard piston stop would be more accurate.  Mark both sides and split the difference.

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