Bushing S rods
Turbo Mini Forums

Has anyone bushed the small end of S rods to make them shorter?

The idea is to run a stroked crank (84mm) and 73.5mm Acralites from Avonbar, rather than cutting material from the top of the piston and losing some of the dish (i need as much as possible due to only having 24cc chambers in the 7 port) I should be able to effectivly shorten the rods by the amount needed, i make the amount I need to offset the small end 1.335mm

84-81.33=2.67/2=1.335mm (50 thou)

Without looking at a rod this sounds feasible enough, but has anyone dabbled with this?

i wouldn't try making offset bushes and then pressing them in, they could end up all in different places, you wouls need to press a solid bush in then set it up an a jig and bore it to siut ,that way all 4 rods go on the same jig, using the big end as you datum for length.

carl

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now that ive read you post properly,lol
you really need to remove 2.66 mm of the main rod body and resize the big end

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I hadn't thought that far ahead as its just an idea but thats good advice.

I was thinking something like bore an oversize hole where the new centre needs to be, then fit a bush and ream to size for a floating pin with PTFE buttons.

mind you this is a bit beyond my engineering skill so it would be farmed out...


Cheers Carl.

Ah! wrote the above before seening your second post, thats a top idea!! are you sure about the 2.66mm though? Is it not just the 1.33 plus a little so the rod cleans up? or am I being dense?

Edited by Joe C on 19th Sep, 2006.

Are you sure the 84mm is not actualy 84.33mm (81.33 +3 =84.33)

any way what ever it is the crank throw is half as long as the stroke so the little end centers at TDC are only 1.33mm higher up the bore and 1.33mm lower down the bore at BDC making 2.66mm overall

ah, yes it may be 84.33, I thought the most you could offset grind to was 84, but apparently not after checking,

So basicly the piston will stick out the block 1.5 mm but this can be lost on the big end.