Increasing bore on M30B28

[okorn]

Hello!

I am from Argentina and here getting an M30B35 engine is almost impossible, they are hard to find.

I recently purchased an E12 528i (M30B28) 1981 with a dogleg gearbox and I want to restore it slowly as the car had some rough time the last few years.
At some point I want to redo the engine and I was thinking the possibility to bore it so that it can be 3.5. Is this possible?The machinery cost in Argentina is not that expensive but I saw a post across the internet that stated that the B28 has waterways between the cylinders and for that reason I will run into those before I reach 94 mm bore. Do you know if the laters block from M30 as mine still have waterways? I bought a 3.5 crank which I got for a few bucks but well I dont know if my idea will actually work out.

Thanks!
Regards,
Oliver


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[digger]

Do you have the block in front of you ? Get a cheap ultrasonic thickness gauge. Are bores Siamese or does water pass between?