Design of the 1MZ V6?
All the literature refers to the V6 engines as "60° bank angle". This is very common (although not the only angle used in production engines), and appears to be the standard for all Toyota engines.
The angle is generally chosen from balancing a list of parameters:
1. smoothness (firing order)
2. production expense
3. engine height vs. width (60° is taller but narrower than 90°)
The bank angle is generally an even fraction of 720° to give even separation of cycles between cylinders:
2 cylinder 360°
3 cylinder 240°
4 cylinder 180°
5 cylinder 144°
6 cylinder 120°
8 cylinder 90°
60° fires 1 cylinder every 120° of crankshaft rotation - the firing (power) impulses are exactly even.
So far, so good?
Then I read from "Turbo Magazine" Project MR6: "The 1MZ crankshaft is a solid forging with offset crank pins on opposing cylinders for even-fire operation." (confirmed by photographs).
Looking at the crank - yes, pairs of journals are offset quite a bit.
The question is why?
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