Engine build math
Thread Starter
|
Freshman User
Joined: May 2005
Posts: 48
Likes: 0
From: Lucan, ON
Engine build math
Can someone confirm (or trash as appropriate) these numbers for me as they apply to re-building my '79 460 D9TE block:
block deck height: 10.322
crank stroke: 3.85
rod length: 6.605
stock piston compression height: 1.792?
This seems to work, as:
3.85/2 + 6.605 + 1.792 = 10.322 (equals zero deck height).
But then I have other info that says stock there should be about a 0.032 clearance between top of the piston and the deck?
If that were true, and the crank/rod values are fixed as above, it would mean the piston compression height is 1.760??
Once I have my block apart (winter project) I can actually verify this of course.
Trying to figure out what compression height piston I will want, to get as close to possible zero deck height (that IS the desired, right?). I realize the shop will be taking some surface off the block too.
Rob.
block deck height: 10.322
crank stroke: 3.85
rod length: 6.605
stock piston compression height: 1.792?
This seems to work, as:
3.85/2 + 6.605 + 1.792 = 10.322 (equals zero deck height).
But then I have other info that says stock there should be about a 0.032 clearance between top of the piston and the deck?
If that were true, and the crank/rod values are fixed as above, it would mean the piston compression height is 1.760??
Once I have my block apart (winter project) I can actually verify this of course.
Trying to figure out what compression height piston I will want, to get as close to possible zero deck height (that IS the desired, right?). I realize the shop will be taking some surface off the block too.
Rob.
Hotshot
Joined: Dec 2003
Posts: 18,423
Likes: 9
From: iowa
get your pistons and do a trial fit into the block and measure the 4 corners with a dial indicator keeping track of that and give those numbers to the machine shop and have them deck the block to that.
they most likely will take the shortest distance and square the entire block to that one low one which should give you zero deck all the way around.
Trying to gauge based on what the block is "supposed" to be will net you a wrong choice everytime. when I measured my block the readings were low of .006 to high of .032 in the hole with new pistons, and yes the block was that far out of square. (and that was after having the a line hone done)
they most likely will take the shortest distance and square the entire block to that one low one which should give you zero deck all the way around.
Trying to gauge based on what the block is "supposed" to be will net you a wrong choice everytime. when I measured my block the readings were low of .006 to high of .032 in the hole with new pistons, and yes the block was that far out of square. (and that was after having the a line hone done)
