Discussion in 'Hybrid Z cars' started by jonbills, Apr 5, 2020.
92.5 is quite something.
Having the exact same number of atoms would be hard; they'll be within a gramme or so.
Taking the edges off, I expect I'll be removing maybe 0.1g. And for comparison, the rods out of my old L24 varied between 735 and 743g. (actually one was 712, but it was a mismatched replacement).
So here’s a challenge: weigh each one before and after, let’s see what the reality of it would be. It would be interesting to know.
The cylinder walls on Alan’s photo look mighty thin. I’m on the phone so can’t zoom in enough to read the widths + being the wrong side of 25, my eyes are getting worse!
I'll try to remember when I get them back.
I can't read them, but I expect the calipers say 3.5mm.
I reckon 2.25mm
96 - (2 *(92.5/2)) = 3.5 was my calculation.
how does yours go Rob?
I tried to read the gauge.
If I remember correctly, the Wiseco pistons I used in my RB had about a 0.2g variation straight of the box.
The Manley rods started with about 6g difference but the ends were all over the place.
It took quite a bit of work on the belt sander to match all the big ends and all the small ends.
I ended up with each assembly (piston, pin and rod) within 0.4g of each other, at which point I figured that was more than good enough for my application.
The article mentions offset-boring some of the cylinders to mitigate differences in support for the liners in each 'hole'. There's differing amounts of metal left in each cylinder after boring, so they shuffled them about a little to suit. Therefore I'd expect different measurements for the gap between each bore. Not much left for the head gasket to sit on...!
I've seen this offset cylinder bore shuffling done on other types of engines too.
Yeh I think it's done on Minis to get 1340cc.
What did the gauge read Alan?
So, coming from a point of utter ignorance on this topic: how does that work with the crank? Are they also using an offset crank of sorts?
I think the offset is across the block not down it. Might be wrong?
No. This is about shuffling bore centres along the centre line of the crankshaft, and the small differences are mitigated by the connecting rods finding their own centres on the crank pins. There's enough clearance between pistons and piston pins, and conrods and crank pins, to allow this.
Don't know. Can't see the scale!
Thanks for that - makes sense.
Wrong side of 25 brah!
Separate names with a comma.