Lately, it's been all about the head swap. In November '04 we constructed a 2.0-liter CR/VTEC motor that never had the chance to dyno. Then, in the 2005 March and April issues we let loose our single-cam Mini Me swap-a-roo, which showed 30 percent more horsepower on the dyno than the engine sans VTEC. Hasport even did a next-gen CR/VTEC swap in October '04 using a K24 bottom and RSX-S top end that gave us 20 more ponies.
This month we revisit the swap that started it all-the LS/VTEC.
For the late bloomers and uninitiated, these cylinder head swaps traditionally involve taking a VTEC cylinder head and transplanting it onto one of Honda's anemic non-VTEC blocks. Only a handful of head/block combinations actually work, but in some instances, like in the aforementioned LS and CR/VTEC methods, power gains can be substantial. Plus, adding VTEC functionality makes driving much more fun.
The LS/VTEC swap generally utilizes a second- ('90 - '93) or third-generation ('94 - '01) Integra LS or RS bottom end and mates it with a B16 or B18 VTEC head. In addition to adding variable valve timing and lift, the modification also increases displacement a small bit. The labor, however, involves rerouting oil pressure to the head and enlarging two dowel holes on the head.
We got the wild hair to build an LS/V when Pro Street Import chief Eugene Castro, who laughed at us for putting together a Mini Me (even though he was the one doing the work), said he could build something much more worthwhile. He just sold his EJ Civic hatch and was piecing the engine together for the new owner. His goal was to put down 210 horses on the Dynojet at PSI.
This one's for the Honda newbies who are just now joining the HT fold. Our how-to, in conjunction with any number of super resources available in print (or if you're feeling lucky, you could try to get help from the Web), and most noobs should have enough info to plan their own stout hybrid. Folks more familiar with the build, though, will hopefully pick up a thing or two from Castro's experience.
Pro Street Import's Eugene Castro kicks off the build by assembling the LS bottom end. It's not a necessary step for the head swap but a useful one for building power. The crankshaft that's in the 1.8-liter non-VTEC block underwent the typical reconditioning, getting balanced and micro-polished. Castro then checks clearances before putting together the rotating assembly. | 
At the ends of the LS connecting rods are P73 Integra Type R pistons, which come slightly domed from the factory. Castro says the slugs raise compression a little from the stock LS ratio of 9.2:1, but that increase is offset by the increase in displacement made with the bigger machined bores. | 
RS Motor Works in Torrance, Calif., prepped the B18B1 block, pressing in sleeves that are 0.5mm over and thereby increasing the bores to 81.5. The overbore raises displacement about 10cc. Castro adds the crankshaft and bearings to the B18, and once the piston rings are gapped and installed, he drops the pistons into the block, too. |