im discussing an engine project with a friend and we are at an impass.

im wondering if swapping LS crank and rods(aftermarket) into a type-r block with 12.5:1 cr will still hold up to continous 9k revs? bore would remain at 81mm with forged pistons but sleeves would be stock.

will this setup rev to 9k as quicky and reliably (under load) as itr rod/stroke ratio?

would the LS crank be as stong as itr crank? i think itr is forged while LS is cast but i am not sure.

please help me clear up some possible misconceptions. thanks.

 

the ls crank is not the weakest link.

they're both forged. the b18c crank is stronger, due to the smaller rod journals (more reinforcement mass), and it's also high-chrome carbon steel, where the ls crank has less chromium.

but, the ls crank can still take the revs with a 1.54:1 r/s ratio. the sideloading will be higher, as will the piston acceleration, which will wear the cylinders at a higher rate, though unless you're planning on some NASCAR-style racing at 9K for extended periods, i wouldn't worry, and even then i'd still be willing to try it. keep in mind that the aftermarket forged pistons and rods are usually lighter than the stock components, which might make life easier on the cyls.

also, i think that Honda tested the b vtec valvetrain to last at about 8k-9k rpm (i could be mistaking this point for the s2k or h22 valvetrain, though) for around 24 hrs (at which the fatigue-life of the rockers was reached), in case you're running some hardcore endurance event. for street, roadrace, auto-x, and drag duty, i wouldn't worry.

 

hey man, his setup will still rev to 9k but you may want to knife edge the crank to make up for the added weight in the rotating assembly. bigger crank and longer rods will of course be heavier creating a slower rev but a knife edged crank will more than make up for it. you souldnt have any problems revving to 9k but i wouldnt go too much higher.

 

thanks for the response

is it worth the compromises (crank strength, piston sideload, higher piston speed) to install the LS rod/stroke ratio in a b18c in order to get some more torque?

my friend (whos knowledge exceeds mine) is saying that the rod/stroke ratio of the LS internals will not be desirable to rev high, and the integrity of the motor will be compromised too b/c of the increased piston sideloading.

from what i have read, yes these facts are true in theory, but i know a few people on h-t are using this setup and im hoping to get some first hand insight instead of searching endless topics abou the same old ****.



Modified by euclid at 10:02 PM 5/9/2004

 

the crank would be knife edged and balanced, be it GSR or LS. also lightweight flywheel and clutch assembly. maybe a fluidamper too.

EDIT: how much more power would the LS rod/stroke make over a stock type-r rod stroke?... leaving all other factors identical in a completely factory-stock b18c

 

there is no way to know how much more power it will make. but in my opinion, if its built well, and maintained well, you can rev to 9000 rpm. not all the time, but when needed. remember though, if your not making power up that high, there is no point to rev that high. yes it will sideload it more, but not much more than a gsr or a type r. the r/s ratio is only .04 worse i beleive (gsr = 1.58:1, ls = 1.54:1 correct?).

 

I'm doing this set up.
gsr block with ls crank/rod/jdm p30 piston and b16 head
a lighten flywheel and lsd will help that slow rev

 

Consider having the piston skirts coated with an anti-friction/dry-film coating. This will enhance the lubricity between the piston skirts and cylinder wall, improving life of interface.


Consider:
1-888-POLYDYN
www. polydyn.com

 

hey, i got an idea for you to consider. might be a little bit better for your setup. since you are considering aftermarket pistons, why not use an LS crank, ITR or GSR Rods, and pistons with either deeper valve releifs or the wrist pins 0.9mm higher. thats the differance in rod lengths. gives a better r/s ratio for barely any more money. im sure some pistons that are meant for race cams will have deep enough valve releifs that you can just use them with no modifying. these gsr rods arent needed but if you really are worried about r/s, it wont hurt anything.
also a larger displacement will give more power depending on your compression and other variables. so it might not give much more power on a turbo motor since the c/r is low, but on an all motor race car it will make more differance than you could imagine.

 

Piston speeds, r/s ratio, or side load will not be too high with an 89mm crank @ 9k.

There are tons of street cars out there that go for years with ls blocks that see 9500 plus daily!


All of things mentioned above are good ideas though, I use them as well (poly side coatings on yur pistons, relocated wrist pins, etc..)

 

do not knife edge a gsr/itr/LS crank.

just get them balanced.

LS crank all the way.

get aftermarket rods, like custom cunninghams or crower ultra lites.

the RS difference is barely anything to worry about IMO.

 

why would it be bad to knife edge the crank?

again, is the difference even noticable between 1.54 and 1.58 RS.. power wise?

 

rs doesnt affect power. rotational mass and engine displacement do.

 

hi peeps...

Im also planning this setup.. my friend is selling me a 85mm wiseco piston 13:1 or arias 84mm 12:1 cr what should I take or any piston size reccomended?

would you suggest to me using an 89mm crank Or will I just stick up at a stock b18c5 crank? whats the difference in terms of durability? actually I got a LS crank before i bought the block..


also looking for LS RODS(aftermarket): paypal only. tnxs...

 

considering the RS in this case directly affects the displacement and rotating mass, technically the RS is making a difference in power.

assuming the crank weight is the same between the LS and GSR, will the LS crank and rods make a noticable difference in an 81mm bore?

 

just give up the RS bullshit...it's not something you ever need to worry about when it's still in the 1.5 range

but the LS crank will have no negative side effect...except less traction

this is one of the best thigns you can do for a b-series

 

good to know that RS reliabilty factors are nothing to worry about, but nobody has answered my other question.

it will cost more $ to use this LS setup b/c of the additional work needed for the crank, the aftermarket rods and pistons.

my friend already has knife-edged GSR crank, stock itr rods, and ctr pistons.

so im wondering how much of a power difference the additional 50cc(?) of displacement will make with the LS setup (assuming CR stays the same between the two setups).

it might not be worth the additional cost and work.

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by KraZEtEggIE &raquo;</TD></TR><TR><TD CLASS="quote">hey, i got an idea for you to consider. might be a little bit better for your setup. since you are considering aftermarket pistons, why not use an LS crank, ITR or GSR Rods, and pistons with either deeper valve releifs or the wrist pins 0.9mm higher. thats the differance in rod lengths. gives a better r/s ratio for barely any more money. im sure some pistons that are meant for race cams will have deep enough valve releifs that you can just use them with no modifying. these gsr rods arent needed but if you really are worried about r/s, it wont hurt anything.
also a larger displacement will give more power depending on your compression and other variables. so it might not give much more power on a turbo motor since the c/r is low, but on an all motor race car it will make more differance than you could imagine.</TD></TR></TABLE>

b18c rods are too narrow to cover the oiling holes on the b18a/b (& b20b/z) crank, and if you're bothering with custom pistons, you might as well get better rods also. even with deep valve reliefs, with such little piston-to-valve clearance on a piston w/pin in stock location, ls crank, and b18c-length rods, you'd better use low lift cams- not worth it.

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by slofu &raquo;</TD></TR><TR><TD CLASS="quote">

b18c rods are too narrow to cover the oiling holes on the b18a/b (& b20b/z) crank, and if you're bothering with custom pistons, you might as well get better rods also. even with deep valve reliefs, with such little piston-to-valve clearance on a piston w/pin in stock location, ls crank, and b18c-length rods, you'd better use low lift cams- not worth it. </TD></TR></TABLE>
people are already doing it. simply droppin gsr rods and crank in an ls. raises the compression quite a bit and never had any real problems.
<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by euclid &raquo;</TD></TR><TR><TD CLASS="quote">it will cost more $ to use this LS setup b/c of the additional work needed for the crank, the aftermarket rods and pistons.
my friend already has knife-edged GSR crank, stock itr rods, and ctr pistons.
it might not be worth the additional cost and work. </TD></TR></TABLE>
if its all motor id say its worth it. but y would u use aftermarket ls or stock itr? just use shotpeened ls rods.

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by bigbore &raquo;</TD></TR><TR><TD CLASS="quote">hi peeps...

Im also planning this setup.. my friend is selling me a 85mm wiseco piston 13:1 or arias 84mm 12:1 cr what should I take or any piston size reccomended?

would you suggest to me using an 89mm crank Or will I just stick up at a stock b18c5 crank? whats the difference in terms of durability? actually I got a LS crank before i bought the block..


also looking for LS RODS(aftermarket): paypal only. tnxs...
</TD></TR></TABLE>
you are gonna need to sleeve the block either way. you can only bore a non-b20 block to like 82mm without sleeves. ls crank is the ****. you will def notice the extra torque

 

Use a set of rods that are +.137" longer than stock LS and the LR ratio will be the same as the GSR. Of course, you'll also need pistons with the pin moved up .137" too...

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by GSRswapandslow. &raquo;</TD></TR><TR><TD CLASS="quote">just give up the RS bullshit...it's not something you ever need to worry about when it's still in the 1.5 range

but the LS crank will have no negative side effect...except less traction

this is one of the best thigns you can do for a b-series</TD></TR></TABLE>

Werd.

 

thanks for all the replies