Why can't you check deck height by placing a straight edge across the bore and use a feeler gage to check the gap between the piston and the straight edge (with the piston at TDC, of course)?

 

Actually you can.

 

I copied a tool I saw at the machine shop. Take an old main crank cap and drill a hole in it using a drill press, then spot weld a dial indicator in at the appropriate height. Using one bolt hole in the deck, zero it on the deck and then move it such that the dial contacts near the center of the piston, or directly over the pin.

Turning the crank in direction of rotation will give a precise reading of deck height..

 

Actually you'd probably want the stop to stop the piston about an 1" from TDC... piston speed is highest in this region for the same reason... very little crank angle produces much higher piston travel (think of the slope of a sine wave). The more piston travel you have for the same rotation of a crank, the less a slight tolerance/inaccuracy will have on your final result.

Yes, this is the similar geometry that slows pistons at TDC and causes dwell... making it tough to nail down actual TDC @ TDC. Trig is cool.

I belive this is the ideal way to degree a cam and reccomended by CompCams. While you have it at TDC, make sure you take time to double-check the timing marks on the balancer.

As long as your piston stop is solidly mounted, mid-cylinder is technically the most accurate way to find TDC.

 

i use a yard stick to measure it


brook

 

That'll work, ya got plenty of number's to choose from.