For those that know dick about machine work....

[Quattro_Krant]

Very nice

[Inn-Tune]

@turbo ls1 ss

1/4 gram? wow!

Yup. When you think about the tolerances as a percentage it makes more sense. We’re generally dealing with smaller bore, lighter weight pistons. On a big bore V8 piston the same percent tolerance would be a larger actual value.

[psychopjv]

@Inn-Tune

Yup. When you think about the tolerances as a percentage it makes more sense. We’re generally dealing with smaller bore, lighter weight pistons. On a big bore V8 piston the same percent tolerance would be a larger actual value.

oh boy he’s an engine racist!!! i keed…:hitit:

[BDR5oh]

@Inn-Tune

Yup. When you think about the tolerances as a percentage it makes more sense. We’re generally dealing with smaller bore, lighter weight pistons. On a big bore V8 piston the same percent tolerance would be a larger actual value.

I just got done weighing my rods and pistons for my notch motor …

and to my amazement … all 8 are within 5 grams of each other … ranging from 1250g on the low end 1255g on the high …

Keep in mind thats rod and piston … and … all my pistons match a correct date code … but the rods vary from the 60’s - 90’s … all within a couple of grams … now thats good quality casting control … to span 30+ years and only be a couple of grams off

[turbo_ls1_ss]

my rods were within 1.5 grams out of the box, and the pistons i believe were within 1 or 2 as well. callies rods and diamonds made to order pistons

[Inn-Tune]

I happened to notice this today…another guy whose Wiseco’s were off. I’m not picking on Wiseco…just mentioning who made them. We didn’t build this one. The pistons were listed as 3.3661" on the spec sheet.

#4 piston measured out to 3.3630"
#3 piston measured out to 3.3625"
#2 piston measured out to 3.3605"
#1 piston measured out to 3.3620"

Wiseco’s recommended piston to wall clearance was .0030" and the variance in piston size was .0025" LOL. Not to mention they were all smaller than what what was on the spec sheet by more than the recommended piston to wall clearance so if they had bored before the pistons arrived, they would have needed another set of pistons. This is why you have to measure each piston and each bore and THEN bore/hone each bore to match a given piston if you want to do this right.

[Jack]

@Inn-Tune

This is why you have to measure each piston and each bore and THEN bore/hone each bore to match a given piston if you want to do this right.

Wouldn’t you’re CCs be different across the board then?

Take these 2 values into account: 3.3630 - 3.3605, because it is 2 out of the 4 cylinders.
Now you have say… 3" of stroke… without a calculator or the drive to open the one on my comp I would imagine that the larger hole would have more volume available and the compression would vary “drastically” across the head. No?