LS/VTEC buildup ques

i did a search and didn’t really find any answers to my question(s)… so i hope this doesn’t seem repetitive

i was looking on and somebody told me it’s best to upgrade the bottom of the block (ie rods, pistons, bearings). if I were to do this, first, would you guys suggest I grab ITR parts/GSR what are the clearences, etc? AND would I be able to keep my non-vtec setup with just the upgraded bottom end?

btw i have a 90 b18a with 200,000miles

you’ll want to stick w/ the ls rods. just have them shot peened and/or cryo treated. also, arp rod bolts are pretty much a necessity. You could upgrade the rods to aftermarket ones, but aftermarket are expensive, and most likely unless you’re going turbo you won’t need them to be that strong.

as for pistons you’ll just want to bump up the compression. Some jdm itr pistons are good for the ls/vtec. w/ a pr3 head i believe they yeild a compression of somewhere around 11:1 (go check somewhere for sure, cause i thats very round estimate). note that you will have to have the rods shaved 1mm on each side in order for any itr or other b18c pistons to fit (pr3, p30, and p61 will fit w/o having the rod shaved).

you’ll also want to perform a complete rebuild: new bearings, gaskets, seals, rings… bore/hone/deck/balance… the whole nine yards.

yes, you could stay non vtec w/ this modded bottom end. and actually if you are planning on modding your b18a, its a good idea to do these mods anyway. I was previously thinking about going ls/vtec. I was going to do it in 2 stages:

-buy spare b18a/b block and build it up
-swap this built block into your car w/ the stock head

-buy complete b16a swap
-use head, tranny, and ecu from b16a and put together the ls/vtec

Overall i priced this to cost about $2500. Give or take a couple hundred depending on what kind of deals you get. (oh, only includes the machine labor… all installation labor is not accounted for).

from personal experience, and doing all the installation yourself, is your car out of service for a long time installing everything to complete the bottom end?

like i was wondering if i should go ahead and buy a spare b18a/b short block to work on to keep my car on the road…


well, i don’t have any personal experience with that, so i can’t really say for sure. but if you’re installing it yourself, and have never done it before, and need your car to be driveable, i’d just buy a spare block. you can pick one up for around $200, or even less sometimes. and then sell your stock one later on… so in the end you’ll break even.

with all this said i would like to mention the poorman’s itr setup. People often say they are going ls/vtec because they can’t afford a gsr or better vtec swap. But the reality is that you can do a poorman’s itr for the same amount or maybe even less than you can build an ls/vtec. and the best thing is that it will have the honda reliability that the ls/vtec might not, plus its ability to rev will be much better.

sorry, what’s the difference between the poor man’s ITR and LS/VTEC ?

poor man ITR has both a VTEC bock and VTEC head,GSR with ITR head…and a better poor man’s ITR is with ITR pistons etc.

LS/VTEC has a nonVTEC block and a VTEC head…a better LS/VTEC is having ITR or CTR pistons…


the poorman’s itr is by definition a b18c1 block, with any pr3 head on it (b16a, b17a, itr, ctr). and personally i thing it has to have at least some itr pistons as well.

this differs from the ls/vtec in that the ls/vtec uses the ls block, okay.

now you say the “poor man’s itr” is stronger than the ls/vtec, well atleast it is more reliable?

the only thing, i don’t understand how the b18b block is any less reliable than the b18c1…


you really need to do a search on ls/vtec’s and read up on this stuff. the whole debate about ls/vtec is this (this is just an overview… go read up on it for details):

pro: added displacement = more torque and more hp

con: poor rod/stroke ratio = engine is not as happy to rev high. Vtec is made for high rpms, not low rpms… to make really good power w/ vtec you need to rev high. reving high w/ the ls block could be dangerous… the stock bottom end won’t hold up to what a stock vtec bottom end will. This can cause reliability issues. Plus, if you get some crazy cams in the future you won’t be able to take full advantage of them because it won’t be safe to take your engine to 9-9.5k rpms.

con: oil delivery. I realy don’t know the details about this. some people say its an issue, others don’t. research it for yourself.

honda designed the b18c1 block differently than the b18a/b for a reason (cost wise in R&D it would have been cheaper for them just to modify an ls block… the fact that they created a whole new block says something). the b18c bottom end gives slightly less displacement, but yeilds a better rod stroke ratio, as well as a block guard from the factor. both things help the engine to be more reliable at higher revs.

U said u can get a block for $200? Where do u get it from? I need a B20z block though.

i said you can get a b18a/ block for $200. That would be used just from someone who needs to sell their’s. When i was looking i found many at places like: and

the b20 block is gonna be a lot more expensive. I think you can get a b20 block for around $800-$1000.