So I'm in the process of building my CR-X and since its as cold as Santa's ********* outside, Im pondering a little "why the f*** not" project. I've got a B16 crank and an LS block, and Im interested in pairing the two and seeing what I get. Custom rods to compensate for the shorter stroke, possibly custom pistons to fit whatever isn't covered by the rods. *Maybe* a vtec head to top it all off. In theory (based on what I know/have researched) ill end up with a motor that will rev to high heaven but make crap power in the low end. Maybe in the top end too. I have no idea. But I think itd be an interesting project, just for the giggles anyways. If anyone has any constructive ideas or possibly even experience with that combo, id love to hear it. If you think its a dumb idea, youre right. But im not using the parts for anything else, so im gonna do it anyways.

P.S. Im also considering dropping the LS crank in the B16 block, with custom rods/pistons as well. Pretty much the antithesis of what I described above. So any advice on that would be nice too.

P.P.S. Neither of these are going to be the motor for my CR-X. I'd just drop them in a shell and see what I get

 

i don't see the point, as you're gonna end up with a b16b bottom end without the strength of the girdle. not my car though i suppose.

 

forgot to mention that I have a Z10 machined girdle in my parts pile as well. didn't even think of that, thanks!

 

After doing some research, you are indeed right kyden. By "destroking" the B18, I will more or less be making a B16B. Which, while perhaps rather pointless, might end up cheaper than actually finding a useable B16B bottom end. On the other end of the spectrum however, the B16 with a B18 crankshaft is very difficult to find any existing information on, and I am rather interested in how it ends up working.

 

i think that ls block/b16 crank combo puts the compression beyond stupid low, like high 6's low 7's.


opposite may be true that b16 block ls crank/rods may put the piston out of the hole a bit. not totally sure id get on and use some the of the compression calculators

 

blackeg, yeah that's correct. I think with my (quick) calculations, the compression would be right around 6, assuming I went LS-VTec and used a B16 head. The B16 with the LS crank would brutally bludgeon the head with the pistons. Hence the custom rods, to compensate/correct for the change in stroke.

 

What is keeping you from running either a true B16 or true LS bottom end? If you have a LS block, get a 89mm crank and rods and go from there. Putting a B16 crank in a LS block WITHOUT using B16B rods is pointless. And putting a bunch of cash into it (custom made rods/pistons) just isn't practical for a B16 crank setup anyways. (Unless you race in a specific class that this is needed)

In short, save your time and money and either get a B16 block for the crank, or get a 89mm crank for your LS block. Keep it simple.

If you are trying to find a 89mm crank and rods and can't do so locally, PM me, I have a spare crank and rods in my garage.

 

running an ls crank in the b16 block would give u a terrible r/s ratio. The idea of destroking the ls block is cool, but you dont have a girdle.

If you want to do a destroke build grab a b20 block to bump your displacement up. Get a super long rod with big rod journal and shallow piston. Balance everything. With the right head and induction system it will be sweet.

 

Destroking 4 cyclinders is rather pointless. We are torqueless to begin with, and everyone knows power is a direct component to torque. V8 builds are totally different...there are 8 cylinders ad many other ways to make up power. with the displacement they offer.

I can see going from the 89mm stroke to the 87mm stroke in some applications, but rarely would I ever recommend destroking a motor, unless it was over-stroked (95mm b series or something).

 

^ not entirely true. The F20b is essentially a destroked H22, leading to a much better rod/stroke ratio and still puts down decent power in stock form albeit less torque

 

^^^thats a 2L motor...were talking an 89mm 1.8 to a 77mm 1.6. HUGE step backwards. and he's losing compression on top of it. Turbo or nitrous. Period.
R/S ratio isn't everything.

 

[QUOTE=93egSLEEPER;49385806R/S ratio isn't everything.[/QUOTE]


yup. my 84.5mm gsr block uses a 89mm ls crank. on the limiter going down the track it datalogs 9200-9300 rpm. aint no thang (gotta thank my 85lb supertech valvesprings)

 

Im right there with you bro. Just giving options to the OP, you never know what route some people want to go. I wouldn't ever do a destroke build like that unless with was forced induction to make up for the huge torque loss.