i just bought a deck bridge with a dial indicator
and i was wondering how do i go about setting it up. i have countless books that have photos of checking deck height but they really dont tell you how to properly set it up. thanks for the help

i forgot to mention that i want to measure piston deck height

ANYBODY??

Are you trying to measure the deck height of the block, or the amount of height DIFFERENCE between the block deck and piston head?

If you are only looking for the difference, put the bridge on the deck surface with dial indicator across the block, and zero the dial. Then move the bridge so the indicator is on the piston head, directly above the pin. If you're right over the pin, the rocking of the piston won't affect your readings. You'll also want to go to the "top" or "bottom" edge, so that you can rock the piston, to determine how much it moves.

Plan your quench based on the HIGHEST position of the piston, as it's going to rock in the bore when the engine runs.

We measure the deck height of the center line of the crank to the deck.

Originally posted by Schurkey:
Are you trying to measure the deck height of the block, or the amount of height DIFFERENCE between the block deck and piston head?

If you are only looking for the difference, put the bridge on the deck surface with dial indicator across the block, and zero the dial. Then move the bridge so the indicator is on the piston head, directly above the pin. If you're right over the pin, the rocking of the piston won't affect your readings. You'll also want to go to the "top" or "bottom" edge, so that you can rock the piston, to determine how much it moves.

Plan your quench based on the HIGHEST position of the piston, as it's going to rock in the bore when the engine runs. =

Gonna have to disagree with this a bit ;)

First, it is pretty hard to measure the center of any piston except a flat top.

Second, you do not set your quench height based on the highest reading on a piston that is rocked over.
The quench is the distance from the head to the piston when the piston is square in the bore.
This is part of the reason you need more than zero quench.

As Carl stated the deck height is the distance from the center of the main bore to the top of the block.

The piston to deck height is what you are measuring.
This is commonly referred to as deck height but this isn't really correct.

The best way to measure a non flat top piston is, after zeroing your indicator, to set your indicator on the flat or quench part of the piston, rock it all the way to one skirt or side, record the measurement. Rock the piston against the other skirt & record the measurement.
Divide the total of these numbers by two & that is as close to what your piston to deck height will be.
Do it a few times & you will get a "feel" for when the piston is "rocked" over all the way
If you have a flat top piston then you can use the center of the piston.

Mike, what about measuring directly over the pin at the quench space beside the dome?

Originally posted by Pat Kelley:
Mike, what about measuring directly over the pin at the quench space beside the dome? =
Hi Pat,
Most domes roll almost to the edge of the piston & don't leave much if any flat but if there is enough of a flat I guess it would work.
You would probably want to check both sides as I think you will find it can be rocked quite a bit considering it is supported from about 7" away & at the center & you will end up with pretty bad repeatability ;)
I prefer to use the center or "rock" the piston on the quench side & split the difference.
Figure it is about as close as you are going to get.

Yup, you're more right than I was. I have flat-tops on the brain.

And I learned about quench distance vs. piston rock. Thank you.