Dial Indicator Setup (Deck Height)
 

I'm trying to figure out the best way to setup and use my dial indicator to measure deck height on my flat top 3.3L CIS pistons / Cylinders. Seems to me you would need to mount the indicator to allow you to set it at 0 when the piston is at top dead center and then measure then rotate it over to measure the span between that and the top of the cylinder but I can't imagine you'd retain any accuracy once you moved the mount.

Probably missing something very simple in my logic.

Rob,

It's call the "Jo block" method or Gage block. (Hardly anyone calls them Johansen blocks anymore).

The procedure entails using a depth gauge base on your dial indicator, resting on a pair of identical gage blocks, which in turn rest on the edge of the cylinder.

• The indicator, base and gage blocks are placed on a flat surface like a surface plate or piece of glass
• The indicator is moved down so that there is slight preload on the tip (needle moves off zero) and then the screw holding the indicator is tightened
• The gauge scale is turned to set zero opposite the indicator position
• With the indicator zeroed, the entire stack is picked up and moved to the top of the cylinder. The gage blocks rest on the cylinder edge
• Holding the stack tightly, the crank is rotated to bring the piston to TDC.
• At TDC, the indicator point will be depressed and the indicator will read the sum of dome height and deck height. Subtract the dome height to get the deck height

Here is a photo of when I used this method to measure deck. Note that you need an indicator with a stroke greater than your anticipated dome height. A 25mm travel indicator would be fine.


http://forums.pelicanparts.com/uploa...1217119703.jpg