Unohdude

My z6 spun a rob bearing so now its time to swap. My buddy has a B20z2 that has 45,000 miles on it but its bored 40 over on stock sleeves. He wants 350 plus my head and ecu. Anybody know of a B20 with stock sleeves punched out? If so whats the miles on it, if its still running? I was also thinking B20 Vtec. Not quite sure yet. Definitely getting gsr trans.

Mr. EG

85mm will work just fine. I was going to go 85mm (from my 84.5mm setup) on my B20 VTEC, but decided not to. Just keep in mind you have a Gs-R head and with the wrong piston selection you may be SOL. An ideal setup would be a set of RS Machine ITR 85mm bore pistons on stock rods and ARP rod bolts. You can make great power on this setup if built correctly, don't listen to the idiot that is going to state "B20 VTEC/ LS VTEC's are unreliable". If built correctly they can make great reliable power. Make sure you have a good tune and break the motor in properly.

9secondcivic

40 over is already past the service limit....if u build that block chances are it gonna blow up....if u have the money sleeve it...aebs does good sleeving i had my b-series done there a year ago...and the mileage on that block who knows who know why it was rebuilt before ....b20 vtec is sick and can make very good power and be very reliable!!!!..BUT u gotta build it right !!!!!! even if its stock b20 vtec other wise its gonna blow up...

Mr. EG

.40 over would be 85mm, which is very do-able. post this in the all motor section of the forum and they will give you the same answer.

NotAJDMFanBoy

If it's already 85 then standard practice dictates it be bored out further to match the pistons used. Few people do though, and they're fine.

B20s are cheap. D series VTEC heads aren't worth too much, and OBD2 ECUs are undesirable. It's your choice.

Unohdude

Thanks to those that have replied already. I attend The university of Northwestern Ohio for High Performance so it will be built right. I was just iffy bout the 40 over but i think ill be fine now. I definitely have to research if i need new pistons for vtec. If i do then ill probably stick to the stock head which is milled 20 thousands until i get the cash. Its always the cash!

Mr. EG

If its a "rough" .40 over meaning it technically isn't 3.346 inches you can properly gap the rings and it will work great. If it is 85mm dead on and has been beat on "causing ring wear or mis-shaped cylinders" the block is garbage. Get a dial bore guage and go to town.