Well, I did some more checking of the block and also checked some pistons. Unfortunately the news for each was not great and is adding to the work I have to do.
For those who don't want all the details: I have to deck my block and cut weight off my pistons. (Keep reading below if you like details.)
I checked to see how "square" the block is. The crank centerline defines the heart of the block. You want the deck surface to be the exact same distance from the crank centerline for every cylinder. If is it very different, you end up with different compression in different cylinders so the engine does not run as well. If the value is the same for all 8 cylinders, the block is "square". Less than .002" difference is fine.
For those that haven't seen this done, here is one way to do it:
There is a 2.000" metal bar that goes through your mains. To make the bar fit your mains, there are custom rings that are exactly 2.000" ID and the OD of your block mains. In this picture I am holding a ring for a 440 (the 383/400 rings on already in my block). One each goes in journal #1 and #5.
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Then you take a "T" gauge and measure from the deck of the block on one side (in the picture below I am measuring cylinder #7) down to the metal bar inserted in the step above. In this case, I didn't care about the actual distance - I just set the gauge to read zero. (By the way, the actual length turned out to be 9.968", so this means my reference point was .012" below the factory spec of 9.980" - so this block had been decked before).
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Then, without changing the gauge setup, I measured cylinder #1. It measured -.001", meaning is was .001" LESS distance to the bar than cylinder #7.
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This is actually a good measurement - a .001" difference is good. But then I measured the other side of the block (cylinders 2 & 8). Cylinder 8 measured -.002", and then cylinder 2 measured -.003".
So back to front both sides of my block differ in length by .001", but the even side cylinders bank is .002" less than the odd side. Not a killer, but not great either.
But then the surface finish tipped the scales. The block surface finish is quite rough. If you scrape your fingernails against the surface of the deck you can feel the ridges. This is not great for sealing. Today's technology (head gaskets) like the surface to be more smooth.
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Per se, none of these things are killers, but they are not great collectively - at least not as close as I'd like them. So to clean up the ridges and square up the block, I will deck the block about .005" below my reference point. (That means I will shave off .005" at cylinder #7 and .002" at cylinder #2.)
Bottom line is after decking the block will be smooth and square, but I was hoping not to have to spend the time to do this.
But the big surprise was my pistons. This engine had high end KB (now Icon) forged pistons. I had a few minutes and decided to weigh them to finish getting them ready for later assembly. Weighing each is simple - just plunk it on the scale:
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You want each one to be within a half gram of one another. Piston 1 is shown above at 503.5 grams. Great, then #2, #3, etc.
I was feeling really good until I got to piston #6. WTF?!?! It is 4.5 grams light!
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I expected better from these pistons, and I am disappointed in the large difference. Also, I would be happier if one or two pistons were heavy, then I might have to work on one or two pistons. But now I need to modify 7 pistons to decrease their weight so ALL weigh 499 grams.
Also, these are small and light already, so it won't be easy grinding out 4 grams or so out of each. So how do you do that?
Well, There are little tabs on the insides of the pistons. This is a key area where you can take some material out without sacrificing the strength of the pistons. There are 4 little tabs that can be ground on each piston. In the picture below I colored black in the approximate material shape to remove.
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I'll try to get this done next week, but the highest priority will be to deck the block.