timing the flathead

[t-moss1]

can you time a flathead using a vacume gage? by hooking up a gage to the wiper port, then moving the advance, retard plate untill the most vacume is reached?

[34flathead]

i am running a warmed '52 flathead and the best timming is at 19 1/2 inch of vacuum, using the timming light to see where the bump on the pully is just for documentation if i ever need a reference point and dont have a vacuum gauge with me.
rich

[flatjack9]

So what timing did you have at that point?

[Henry/Kokomo]

To answer your question,"Yes".

[34flathead]

i am at 2 degrees btdc or negative 2 degrees, that is assuming ( i know ) that the bump is the actual top dead center.
rich

[flatjack9]

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I believe the bump is 2 -3 deg BTDC.

[Zurekbrau]

That works the best for me to.

Rich

[34flathead]

i have been told that the bump = 2 degrees, so i am negative 2
that is measuring the width of the bump and calling it 2 degrees, it even ran good at negative 4 degrees 18 1/2 inch vacuum, but not 6, had to find the where it starts going bad, but it is best there, 19 1/2 inch vacuum.
lots of people have told me the bump was not an accurate mark? i have not had some one help me find the exact tdc, but if i can find a 15/16 socket to grind down 1/4 inch so i can turn the crank with a breaker bar, i will degree my pulley.
rich

[52merc]

Originally Posted by flatjack9

I believe the bump is 2 -3 deg BTDC.

im with you the timing mark is 3 deg b4tdc,thats where you work from,,ol ron has done lots of testing of this i think its in his book