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Thu May 15, 2014 9:38 pm

I got a stock 1600 dp with new OEM heads from Mexico. I want to go with a good quench. (Yes, I know that will put my CR over 9:1 and that I'm building a grenade). From what I've read you can you can get a quench off the combustion chamber if the step is the same or greater diameter than the cylinder bore and of course bigger than the piston diameter. But I'm having a bit of trouble measuring its depth. I have a cheap caliper with the tail that protrudes for measuring depth, but I keep getting very different measurements in the same place. Any suggestions?

Fri May 16, 2014 1:59 am

To get accurate step depth measurments you will need a depth micrometer

Tue Jun 10, 2014 8:23 pm

Here's probably a dumb idea.

What if I take the CC of the whole combustion chamber including the step, take away the CC of the combustion chamber without the step so as to get the CC of just the step, then divide that by the pi R squared of the inside diameter of the step?

Might not be as accurate of the depth micrometer. Maybe I should talk to my machinist.

Tue Jun 10, 2014 9:23 pm

Hold your calipers vertical and measure in the same place 3 times (average the number) ,
if you get a crap reading toss that number out, and measure again,
and then move to a new position and measure again 3 times, do this again at a third location.
Be sure when you do this to always keep your vertical to your measuring surfaces.
Average the 3 average numbers and you'll have a pretty good number to use for calculations.
My bet is your step height is .055”to 060”.