Hello, Datto people.

So I have this A15 that I built and stuffed into an MG Midget. Running well. I am gonna pull the engine/trans for some stuff and am considering lightening the flywheel. Reason is, despite the H89 head, the 260/.425 cam and the twin HIF4 SUs it kinda revs a bit lazy. So with the engine out I am wondering if lightening the flywheel would be worth the trouble to help it rev quickly, to help with quick rev matching when downshifting? Car is only around 1600 lbs and has a 3.9 rear ratio.

Next question: the engine was balanced when I had the machine work done. Are the flywheel neutral balanced or do they have a specified imbalance?

I am wondering if I can have it lightened without messing up the engine balance or if I have to have everything rebalanced?

It is neutral balance, so it does not affect the shortblock balance

Yes, lighten it up. Obtain an A12 flywheel then machine it down from 21 pounds to 14 pounds

Datsun B110 Competition Tune-Up Manual

OK on the 1200 flywheel, but what about the A15 flywheel, which is what I have. Can do the same or?

You can do similar, it will be heavier as it is thicker to start with