Boring out a B-3 engine and final drive for G trans

[Doug Brown]

Has anyone ever done or know if it is safe to bore out B-3 cylinders to either +030" or +040"?

Has anyone ever install the Mazda Speed 4.88 ring and pinion gear set in a G transmission?

Thanks

[Bratboy]

Why not get a 1.6?

[Doug Brown]

The rules for the Festiva drag racing challenge says it has to be a B-3 block, but just about anything else is OK. B-3 blocks I have but they need a little machine shop work to get them in really good condition.

Afterward I can go to a 1.6 B-6 or the BP.

[Bratboy]

Aaaaaahhhhhhhhh.......

[skeeters_keeper]

I think you can find +.030 pistons, but I don't know of anyone that has done it... of course you can hunt around to find pistons from another application that may work at even larger sizes, but I don't think the cylinders can take much more than that.

[firebush357]

I just checked RockAuto and it looks like they aren't selling the oversized pistons anymore for some reason. From my knowledge, the B6 block is basically just a bored out B3 block so there should be plenty of room to go .040 over.

Dickmeyere was making Billet pistons at one point with a lot of suggested gains but they were $800 a set....

[skeeters_keeper]

No, I know you can't bore the block up to B6 size. While externally they are the "same" block the cylinders are different and there isn't enough wall thickness.

[Doug Brown]

OK, ever heard how thick the walls are or if anyone has gone +.040? I may just go +.030 to be safe, but +.040 pistons are available.

[skeeters_keeper]

I haven't... but now I'm kind of curious and I think i have a junk block at home. Maybe I'll cut it up tomorrow and let you know.

[skeeters_keeper]

Mic'd a b3 bore - the wall thickness is ~0.235"
I should have mic'd the B6t block sitting next to it... maybe tomorrow.