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How to measure deck height?

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Old 05-17-2009, 03:46 PM
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Default How to measure deck height?

I have a block that I would like to accurately measure the deck height. Can someone help me out on the proper way to go about it? It's an iron 6.0 that was supposedly zero decked, but I want to know it's deck height.
Old 05-17-2009, 09:52 PM
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First off, all lsx engines have the piston protruding from the bore. If someone tells you they zero decked the block that's Impossible. If anything they had it milled to correct for any warpage or to true up the deck surface.

I think what you're really after is to see how far the pistons are out of the bore. First start with a carbon free piston, then with a dial indicator on the block deck surface, rotate the engine until you're at true top dead center. Then with a machinists straight edge, lay it across the top of the piston. Take your set of feeler guages and find out what fits under the straight edge and the deck surface. This is the quick and dirty way to do it. You may be off a thousandth or so but it's the quick dirty way and fairly accurate.
Old 05-17-2009, 10:30 PM
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Ok, thanks. I thought the iron blocks had the pistons in the whole a bit?

So the only thing measured on deck height is the amount the piston is above or below the actual deck surface?
Old 05-17-2009, 10:41 PM
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The LSx pistons are normally "in the hole" .010-.012 according to the machine shop I used...

Also be sure to check all four corners of the cylinder really..... about 1:30, 4:30, 7:30, and 10:30.. Also a dial indicator doesnt cost that much...
Old 05-17-2009, 11:37 PM
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Originally Posted by Wilde Racing
The LSx pistons are normally "in the hole" .010-.012 according to the machine shop I used...
Out of all the motors Ive built/torn apart, NONE have had a piston in the hole. All that I measured atleast were .08-.09 out of the hole, the others I was doing head swaps on and didnt measure but they were for sure above deck height.

So far Ive worked on 5.3s, LQ4s, LQ9s, LS2s, LS1s, LS6s and a couple of built motors, my 418 was .08 out, my 420 was IIRC .09 out, a forged rod/piston 6.0 block I built was .08 out. Where anyone has gotten a piston in the hole is beyond me.

FYI here is how to measure TRUE deck height
http://www.faliconcranks.com/pdf/rod...ion_height.pdf

I think you were after was the piston protrusion, which is measured with a dial inidicator such as this one. Zero the indicator on the deck then rotate it over on top of the piston and turn the crank until the highest number is achieved.
http://store.summitracing.com/partde...5&autoview=sku
Old 05-18-2009, 12:23 PM
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Out of Hole = LSX
Old 05-20-2009, 03:51 AM
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if your measuring on a bare block, get a large dial caliper and measure from the deck to the main bearing bore (with no bearing installed). then add 1.375 (half of the bearing bore diameter). factory spec is 9.235-9.245.
Old 05-20-2009, 09:22 AM
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As I recall from building my 408, 9.240" is considered "zero decked". All gen III's are supposed to be -0.008 (out of the hole) piston decked.
Old 05-20-2009, 10:17 PM
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Ok, thanks guys. I did some reading as well and I think I got it.

I think I'm going to attempt my own motor build next time... it doesn't seem to be that bad. Hardest part is waiting for the machine shop to finish I'm guessing.
Old 05-20-2009, 10:25 PM
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Originally Posted by TurboBerserker
As I recall from building my 408, 9.240" is considered "zero decked". All gen III's are supposed to be -0.008 (out of the hole) piston decked.
I must have got that mixxed up with mine... This is of course is stock. Mine was out .015 during engine build time....
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