deck height question
Thread Starter
Joined: Sep 2005
Posts: 8,139
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From: Chillicothe/Lima, Ohio
deck height question after fitting my LQ9 block in the CNC machine, and having to take .022 off the deck to get it straight, I'm looking at a 9.2182 deck height according to the CNC machine. does this leave me with too thin of a deck for an 6.0 iron block?
Thread Starter
Joined: Sep 2005
Posts: 8,139
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From: Chillicothe/Lima, Ohio
i figured rightfully so, its only .022. I think i might push my luck and get another .005 taken off it to bring the piston back out where it belongs.
If You took .022" off then You're pistons should be coming out of the holes about .032" to .037" already and the stock gasket compressed is .058" so You would have a .020" quench which is about .010" or .015" less than ideal .
Thread Starter
Joined: Sep 2005
Posts: 8,139
Likes: 10
From: Chillicothe/Lima, Ohio
No, I already got all that figured out. My pistons right now with .022 off the deck are roughly .003 IN the hole. I want to take .005 more off to get them .002 out of The hole and run a .040 gasket for .038 quench area.
Thread Starter
Joined: Sep 2005
Posts: 8,139
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From: Chillicothe/Lima, Ohio
Good looking out tho, thanks for the thought. I've been collecting parts for 2 years for this build with every extra dollar I get, so I've had nothing to do but math lol.
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Thread Starter
Joined: Sep 2005
Posts: 8,139
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From: Chillicothe/Lima, Ohio
Yes. Here is my math...
1.811 half stroke
1.3045 compression depth of piston.
6.100 rods
9.2155 total deck height of rotating assembly.
9.2182 deck height of block.
9.2182 - 9.2155 = .0027 in the hole.
Now I take .005 more off the deck of The block.
.0027 - .005= .0023 out of The hole
Guess after doing it again, I should take .006 off the deck to get me .0033 out of The hole.
1.811 half stroke
1.3045 compression depth of piston.
6.100 rods
9.2155 total deck height of rotating assembly.
9.2182 deck height of block.
9.2182 - 9.2155 = .0027 in the hole.
Now I take .005 more off the deck of The block.
.0027 - .005= .0023 out of The hole
Guess after doing it again, I should take .006 off the deck to get me .0033 out of The hole.
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Regardless of the math have you put the crank in and verified the height by installing one piston,rod in each corner of the block to be sure? Its better to check than cut first then to find out your block is junk after milling too much.
Thread Starter
Joined: Sep 2005
Posts: 8,139
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From: Chillicothe/Lima, Ohio
Not yet. I am confident the deck is at 9.2182. I have no reason not to trust a 250k cnc machine.
That being said, with known values on the rods, crank and pistons, I am also confident on my math. However, yes I will mock it up and double check before going any further.
But at this point, I haven't put a finish hone on the cylinders, only a rough .025 over bore. I knew when I did all the machining on The cnc machine, I wouldn't be putting it together for a while, so I saved that process for the last minute to be able to hone any surface rust out of the cylinders before final assembly.
So when the time comes to assemble the long block, I will take everything to the shop and hone it, mock it up, double check deck height and finish the final assembly.
Good looking out, thank you for the insight.
That being said, with known values on the rods, crank and pistons, I am also confident on my math. However, yes I will mock it up and double check before going any further.
But at this point, I haven't put a finish hone on the cylinders, only a rough .025 over bore. I knew when I did all the machining on The cnc machine, I wouldn't be putting it together for a while, so I saved that process for the last minute to be able to hone any surface rust out of the cylinders before final assembly.
So when the time comes to assemble the long block, I will take everything to the shop and hone it, mock it up, double check deck height and finish the final assembly.
Good looking out, thank you for the insight.
Thread Starter
Joined: Sep 2005
Posts: 8,139
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From: Chillicothe/Lima, Ohio
Unfortunately, I did this 2 years ago, and since then, my old computer took a **** and I lost all the pictures and videos I took of it on the CNC. next time I am around that way, I will stop in and see what they have on it and try to snap some pictures.
On The Tree
Joined: Feb 2010
Posts: 140
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From: colorado
I remember when you did that.
About that time erea i had posted asking if anyone
ever heard of katechs 4.125 rotating assembly and everyone
seemed doubtful of the reliableness.
I too have been biding my time reading and searching to
find ways for horspower and torque without just throwing a few
thousand at it.
My goal is also to hit that .035 quench mark
I always like to read your input bww for the input
you always seem to have your research done too!
Thread Starter
Joined: Sep 2005
Posts: 8,139
Likes: 10
From: Chillicothe/Lima, Ohio
I remember when you did that.
About that time erea i had posted asking if anyone
ever heard of katechs 4.125 rotating assembly and everyone
seemed doubtful of the reliableness.
I too have been biding my time reading and searching to
find ways for horspower and torque without just throwing a few
thousand at it.
My goal is also to hit that .035 quench mark
I always like to read your input bww for the input
you always seem to have your research done too!
It's tough sometimes, everytime I get on here, I see people talking about their car...getting it tuned, running 11's in the quarter, making 500 hp...etc...and here my car sits, going on 3 years without an engine...
but, oh well...one day it will be done.
as far as the .035 quench, I've found it better to do as much of it as you can with the gasket. I personally like to see the piston as close to 0 deck as possible just to avoid having the piston and the gasket sharing the same space. It tends to create small amounts of turbulance when the piston is at TDC. I know it's not much, probably not even noteworthy, but thats my theory and i'm sticking to it.
I want to go with about .003 out of the hole as opposed to the stock .005 to .008 and make the rest up with the gasket for .037 quench area.
Are they that far off?
That's insane amount of decking for "straightening". WOW!
I'm new to the LS world but that much deviation would make me look for another block...
I'm not saying that it's to much to remove. It's just to much to have to remove before before a straight deck is achieved.
+1 on a mock up (4 corners) before final cut. That's the single best "Anti-Murphy" suggestion of this thread.
Thread Starter
Joined: Sep 2005
Posts: 8,139
Likes: 10
From: Chillicothe/Lima, Ohio
no, they were not that far off. after looking at my papers again, the deck was more like 9.23 as opposed to 9.24
they were .006 across the deck, so i removed .010 roughly.
they were .006 across the deck, so i removed .010 roughly.
TECH Fanatic
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From: Katy, TX