LS/Vtec
 

ok i pretty much have the basic instructions and basic idea on how to build one but i'd like to know how to build a powerfull and reliable one. i have a few questions that i hope someone can answer.

what kind of compression ratio should i expect or shoot for?
am i better off using LS rods and pistons or b16?(i know b16 rods are shorter..read next question)
i plan on running stage 2 cams with upgraded valvetrain. will running ls rods and possibly high comp pistons ---- up and bend my valves?

any input helps

TIA

you building a motor this winter? LUCKY!!! what you using for a head?

l've been poking around ht's allmotor forum a lot recently. definitely use p30(jdm)/pr3(usdm) pistons to bump up the compression. that seems to be a popular combo using oem parts. and you never hear about problems with the valvetrain clearing the valve reliefs or piston to valve clearance issues unlike a b20 (stock pistoned). in those with a mild cam like a ctr, no one dares advance the time at all. and even then, sometimes the valves hit the pistons, sometimes not.

maybe clay the motor for clearance while your at it, just to be safe.

hope some of this helps.

definatly clay it before starting it.

use the LS rods and a high comp. piston.
you can still use a pretty good lift cam cause the releifs in the piston are still there. you won't have piston to valve contact til you start missing with cam gears.

in my gf's motor we are using a b20B block with je 11.5:1 pistons, stock rods, b16 head and valves, crower springs and retainers and stage 2 race cams.

wow lucky gf....looks like ur gonan be raisin a bunch of gear heads in the near future lol

i found this link on H-T http://www.zealautowerks.com/

with LS Block, Crank and rods and P30 head and pistons i'd get a 12.18:1 CR....that's crazy, what octane fuel would i be running??

even if i swap out the p30 slugs for PR4's i still have 11.94:1. is it really that much of a difference? i mean i'm getting a whole b16 motor cheap so why not use what i got.

so if i run a stage 2 cam, ITR valves, dual springs and titanium retainers...might i have a prob with some piston/valve contact?

i'd probably only use the cam gears to kill the valve overlap so maybe moving the intake to -2 or something....you get my drift?

my piston to deck height with the p30's and pr3's would be 0.014 inches

that link rocks!!! it's cool how it has the green light/ yellow light/red light background. the c-speed one is supposed to be inaccurate. the bojanles is the only other one i know of, but it's so primitive.

12ish isn't that high. you figure that a good tuner will able to get the car running right with 91 octane.

you can easily find someone to swap those p30 pistons out for some gsr, but since your using stage 2, you probably want higher compression to get the most amount of power out of those cams.

or maybe or you can destroke it with a gsr crank, there's one fs locally: http://www.honda-tech.com/zerothread?id=1388088

I was just messing around with you're zeal calculator and i found a nice setup for you mark.

Use you're block and crank
B16 Head
PR3 USDM B16 Piston
B16A Rods
3MM Headgasket
You're ending stroke results in 1.54 with a displacment of 1834.72cc

The best part is you'll have a compression ratio of 8:8:1

Perfect for boosting with VETAC yo

P.S even if you're stay with the OEM HG you'll still retain a low 8:9:1:D

P.P.S if you use a B17 connecting rod,You'll acheive a 7:7:1 comp ratio

sorry derek no boost for me.....gonna make something from nothing.

why does the screen change colour?

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relates to how high the compression is it looks like. with your proposed build sub the pistons with pcts and a 1 layer headgasket. it's way red and a wicked high compression.

i did oem gasket and i got yellow

i guess i'll need a block guard and since the LS crank will be taking revs of 8000+ i should probably balance my bottom end....correct?

ya and a crank girdle won't be a bad idea either

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the block guard is deck is usually used in a turbo applications. you should be fine with an open deck. the vtec motors have a gap bridge that attaches the bearing caps together to stablize the bottom end. golden eagle makes one that is money, or you can use on off a vtec motor. most people don't use them. having proper bearing clearance are a lot more important.

btw, i have zero motor building experience, so take what i posted lightly. i have only watched friends put together a couple. thanks a lot, as you got me looking for a block now. :lol: looks like you have a nice project for the winter.

this is a really, really good thread:

http://www.honda-tech.com/zerothread?id=1118097