Flathead Timing.

C

cpr66

New member
Ok...when you are talking about ignition timing on flathead engines, i hear alot of people say timing in the hole. are they refering to the keyway on the crank and flywheel as the hole? any help would be appreciated
 
You really should refer to it as off of TDC, because deck heights can be different on different blocks or piston combo's so measuring a pistons depth 'in the hole' can be misleading. Going off TDC will eliminate any error for block or piston differences. You could use a degree wheel or there are charts that translate degrees into inches before TDC, all you need to know then is the fire point or position of the flywheel in relation to the coil when it's gonna fire. When the right edge of the magnet reaches the outer edge of the right coil leg , that's where it fires so you put the crank at the timing you want, for example a stocker that you want at 29 degrees is right at .195 before TDC, with the crank held at that point you line up the fire marks I mentioned above and torque the flywheel on. Re check after torqueing to see if it moved on you any. Jon
 
Jon Brogden said:
You really should refer to it as off of TDC, because deck heights can be different on different blocks or piston combo's so measuring a pistons depth 'in the hole' can be misleading. Going off TDC will eliminate any error for block or piston differences. You could use a degree wheel or there are charts that translate degrees into inches before TDC, all you need to know then is the fire point or position of the flywheel in relation to the coil when it's gonna fire. When the right edge of the magnet reaches the outer edge of the right coil leg , that's where it fires so you put the crank at the timing you want, for example a stocker that you want at 29 degrees is right at .195 before TDC, with the crank held at that point you line up the fire marks I mentioned above and torque the flywheel on. Re check after torqueing to see if it moved on you any. Jon
Click to expand...

this is correct
 
thanks alot guys for all your help...my next question was gona be.. how do you kmow the reference point on the flywheel as to where it fires...but that clears it up. thanks again.
 
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