[kyosoeg6]

Is there anymore updated info on this thread that people could share for us noobs. There are so many sizes that people run these days.

what do you mean by so many sizes? a k24 crank is a k24 crank.

 

[_Mozz_]

There is a HUGE diference in Balancing from factory between the two cranks.

Have both cranks here in my garage. Both Worked by ERL.


Top K24A1, Bottom is the K24A2 (RBB):
(Mod: Corrected K20a2 (RBB) into the correct K24A2 (RBB))




Will show same parts on both crank after balancing (by same company, same day)

Balanced K20A1


Balanced K24A2




Balanced K24A1


Balanced K24A2




Balanced K24A1


Balanced K24A2



Quite clearly the RBB its a much better balanced Crank..



:new_slayer:
.

 

[Deetz]

To add to this thread, i think the main design advantage to the A2 crank having bigger counterbalances, is the smoothness at higher rpm.

I do know for a fact as an example, on the older B series engines, a Type R crank was actually heavier and had th larger counter balance weight over cranks found in other B18 engines. I kknow that the ITR crank was something like 30% more smooth above 7000 rpm (less vibration), over a stock crank, making the engine run in a more refined way at high rpm

 

[BOMrsxS]

I picked up a JDM K24A over the weekend. The shop had a few bare short blocks and a few cranks all separated. I do not know if I got the crank that was in my block. Assuming I didn't, and I want to be sure it is balanced as best can be, would it make sense to wait to have the crank balanced after I have rods and pistons and have everything balanced together? Or is it smart to have the crank, itself, balanced prior to balancing the entire rotating assembly together? Is it worth it to have the crank lightened at all for an all motor application? This will not be a race engine. It'll be a weekend cruising car, not even a daily driver. Redline won't be higher than 8k.

 

[Lotus]

It makes sense to balance the crank, crank pulley and flywheel and pressure disk starting with the crank itself. It should have near perfect balancing from the factory. Then add the crank pulley and balance, next the FW and balance, then the pressure disk and balance. Lightening the crank is not worth the trouble for a road car. For the rods and pistons, have the piston/pin weight matched to within 0.1g, at least, and rods checked for weight and ideally weight distribution on a rod balance.