Originally Posted by
Toy Civic
If one is going to set up a B series DOHC Honda motor, I have some questions:
1) If you have an installed B18C1 block, normally the correct rotaing assembly is also inside. (GSR crank, rods, and pistons).
2) Can one replace the rotating rotating asembly with an LS crank (89mm stroke versus 87mm GSR stroke) and LS rods (5.394 inches versus 5.430 inch GSR rod length)? If so, do you retain the GSR pistons? I would think you can if the deck heights of a B18C1 block and and an LS B18B block are the same.
3) If this all works out, does there need to be any modification to the block or the cyliders? Will the 2mm longer stroke affect anything?
4) Basically, I'm trying to assess the validity of the ever popular LS VTEC build. If all other things are equal (GSR head, GSR cams, P72 GSR ecu, etc.), then is there any real gains of LS rotaing internals versus GSR rotating internals?
5) Forged pistons versus OEM pistons? If the car is more of a street car, and not so much a drag or track car, is there any benefit of forged versus OEM pistons? The motor would immediately have small power adders such as header, ECU upgrade, mild cams, etc. I may want to boost it 6-8 psi in the future. Yet I want the motor to have as much longevity as close to OEM Honda as possible.
What are your thoughts?
Yes, you can use an LS Crank & Rod's in a GSR block. You might have clearance issues with the Oil Squirter's, but don't quote me on that. The engine will run fine without them, and they are useless if you choose forged pistons.
The main benefit of the longer stroke is a gain in low to mid range torque.
If you plan on boosting, you might as well spend the extra $700 +/- on forged pistons & rod's. For anything under 400 whp, Eagle rods are a popular choice.
If you want my advice:
a) Since an LS block is considerably cheaper than a GSR block, why don't you just use an LS block and a vtec head? Golden Eagle makes an oil supply kit which eliminates the need to tap the block. It will save you money in the long run. I see this as the cheapest option, whether you stay NA or go FI.
b) If you are planning to boost and must have a GSR block, then I would scratch the LS crank. Just use forged piston's and rods, and with proper tuning you could make between 300 & 400 whp. The additional torque provided by the LS crank won't be missed in a FI application, unless your talking serious power. IMO anyway.