I'm am trying to get everything together to do a b20 vtec. I am going to use mahle 12:5:1 pistions for a gsr but there 84 mm so I'm going to put them in my b20. My question is when I go to put this together should I just remove the rods and change the pistions or should I tare the whole thing down and put new bearings in the whole thing. The motor came from hmotors online wwith 38,000 miles and I've only put 2 miles on it if that I took it straight to the body shop to get it painted. Has anyone used mahle pistions or heard of them? Thanks

First off are you using a gsr head? Second mahle pistons are great. The only problem is gsr and b20 wrist pins are in different locations so you have to have your rods modified and you might as well have them shot peened and buy arp rod bots in case you wanna rev past stock b20 red line cause ls and b20 rods arent that strong. So you have everything torn apart you might as well buy all new bearings and completely refresh the bottom end. Hope this helped.

Yes i will be using the gsr b18c1 head. All that mahle has to offer is a 12:5:1 compression for a 84mm bore and thats to high for 92 octane gas so what would you use for pistions. Thanks

Have you checked out supertech? They have pistons made for a b20 with a vtec head and you can get 11.8:1 with the gsr head which would be better for 92 octane. if you dont mind were do you live? the reason i ask is you could go higher compression if you have a e85 fuel source around. Heres there website http://www.supertechperformance.com/