skribblah

i know that people Teenig from the block cause it to maby break off at the block and spill out oil everywhere, but other than that, how exactally have some of you guy's who have had ls/vtec or had friends that had ls/vtec, if it fucked up, how!

thanks

zad5

rod ratio is too low on ls motor (1.54). people think that with a vtec head they can rev higher but its not true. it is the same reason with stroker kits you get more torque but your rod ratio gets messed up which makes ur redline drop. the problem is that when u have a messed up rod ratio the whole geometry gets messed up and puts force on the cylinder walls instead of going up and down and if you rev high it will break the cyclinder wall and coolant will go into your engine. basically what happens i dont know too much so if i said something wrong correct me.

skribblah

i know of the r/s downfall, i mean like, man i had ls/vtec then i busted a ring on #1, or my frined had ls/vtec then he bent a ls rod thos things are gay flemsy or whatever, just spcifics of people who have had or known people with ls/vtecs on what exactally went wrong.

rodrez.

Some of the LS/V's that I've seen fail because the stock rod bolts are weak. Revving past the LS redline, the rod bolts stretch and become brittle, eventually letting go. ARP rod bolts can be purchased cheap, and I highly recommend them.

P1mpSlap

Why are thou running LS/VTEC without forged/balanced components?

ARP bolts are great too. Save your motor for under 100 bux.

skribblah

ok so what i have concluded from a shitload of reading is to be on the safe side, shot peen the LS rods and get ARP rod bolts, then get the GSR / z10 / hybrid garage block girdle and the block should be stright for ~8500RPMs. anyone want to add anything?


Modified by skribblah at 6:28 PM 6/30/2003

mr.beeks

if not done right
you will have oil leaks around the head gasket
for one.
then redline drops if the bottom its not streghten to match the
vtec high reving
another is the head bolts
they tend to let go from the block
thats why they use arp.
therefore it becomes a little more expensive to build the right one
and maintanance wise it requires more attention

skribblah

bibbady bump! more repilys please.

romeo619romeo

umm ls vtec was never ment to be... if that was the case hond would have made it already....its a give and take kinna thing.. but some people dont want to listen.. i want LS vtec and rev to 10k with my turbo kit blah blah blah

ajchen

this is a poor line of reasoning that pops up all over honda-tech.

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by romeo619romeo &raquo;</TD></TR><TR><TD CLASS="quote">umm ls vtec was never ment to be... if that was the case hond would have made it already....</TD></TR></TABLE>

skribblah

yea, i know its stupid, im not wanting to diss anyone but anytime ls/vtec is mentioned, people assume they know what they are talking about and they say stupid **** that is OBVIOUS like " it is as reliable as you build it" and all that other r/s crap. i mean come on guys if you dont have an ls/vtec or have searched and read for a week and have a working knowlage of what to do and how and why it works then dont comment!! it sucks trying to weed out the BS people from people who do know their ****.


again, the purpose of this this thread is to find out if you have a ls/vtec or knew someone with that setup and it blew or whatnot, explain exactally what malfunctioned. once again thanks to the people who know their stuff

JayDM.com

well my basic outlook on it is:
LS bottum end = low flow
VTEC heads= high flow.
if it was math it would still add up to be negative!
and if youve ever taken a VTEC bottum end apart you will see how much VTEC complaint parts are in the block... VTEC is all about oil pressure!

zad5

Copy and Paste - Tuan (Michael Delaney from team-integra) article on automotivetech. i thought maybe some of you guys didn't have user name password or were too lazy to sign up so i decided to copy and paste. but you should check the site out. http://www.automotivetech.org
--------------------------------------------------------------------
LS VTEC and Thoughts on Rod Ratio Affecting Engine Combination

Here's a recent thread I was involved in that captures some basic relationship concepts you may want to discuss:

quote: Original Question Posted by Pollux

I heard that you can change a non-v engine to one with it, with a "VTEC"
block? Does this mean you would basically need to do an engine swap? Has anyond done this? Can someone explain to me what would be involved and what the cost would be?

quote:First Reply by BlackGSR to Question

basically taking off your old head and replacing it with a vtec head


quote:Originally posted by BlackGSR

basically taking off your old head and replacing it with a vtec head

I wish it was that easy. I guess the search function doesn't have anything on LS VTEC eh? or did you not try to look there first? I'm sure we covered this a lot in the past.

Anyway, I suggest you check out these sites:

http://www.c-speedracing.com/h....html

http://www.angelfire.com/sc/thuspeed/lsvtec.html

http://www.geocities.com/Motor....html

the c-speedracing site goes through most of the salient points about the process of putting the combination together.

the key to this setup is WHO does it ....not the parts you should get which is what most novices focus on only, not realizing the impending headache they will face from an improper install.

you need to find a very good machine shop locally who is precise and has a good rep for doing things to spec dead-on (like blueprinting) with aluminum heads and blocks (not just iron domestic blocks). You have to
plug the VTEC oil passage in the VTEC head (usually welding the plug in is better than just using a bolt plug) and then machine the plug down flush with the cylinder head's deck surface. Secondly, since the LS block dowel pins and the VTEC head's dowel pin holes are not aligned, the machine shop must redo the dowel pin holes by slotting them to line things up properly.

The main problem with this setup is, if machining & installing are done improperly by an inexperienced or incompetent shop, you will end up with oil leaks and coolant leaks, since the ducts for oil and coolant in the
head and block are not aligned up...they were never meant to be put together at the factory in the first place and they have to "make" them fit with adjustments at the machine shop.

I always tell LS owners that you can get much more power reliably ,if you invest in a turbo and getting the correct anti-detonation parts , instead of running an LS VTEC.

To run faster than a GSR or ITR with i/h/e, you must upgrade the pistons for higher compression in the LS block. My friend Chistian Gaines runs an LS VTEC with 11:1 CR and makes over 185 peak whp with Type R cams. Chris used to visit us over at Superhonda and gave me good advice.



Most beginners mistakenly think the VTEC head allows them to rev higher.

The rod ratio in the LS VTEC is still the same as the LS...a low 1.54. This does not help your cause in revving higher. I explain why elsewhere, if you do not know what rod ratio means and it's implications on the redline. Beginners often think that the head and VTEC gives them a license to rev higher, when in fact, the rod ratio is what allows you to rev higher safely and reliably. The head just breathes better and VTEC allows variable valve lift/duration to get a peaky powerband in a 4 cylinder engine and at the same time, get decent driveability in the low-mid rpms....that's all...having VTEC is only one part of being able to rev higher...NOT the entire reason.

These concepts don't just apply to the 1.8L LS VTEC . You can apply them to a B20 VTEC which is a CRV bottom end or block (also has the exact same rod length & stroke as the LS!) with any Bseries VTEC head (it also needs the rear dowel pins aligned and the head oil duct shut by a machine shop). You don't rev a stock block 2L B20 VTEC past 8000 rpm either.


If you know of a good local shop then you may still want to look into
doing it...I also recommend http://www.drtracing.com who has done several of these reliably .

quote: Originally posted by 20lb teg

Hey Tuan, what effect does boost have on Rod Ratio's like for instance how much boost could that 1.54 r/r on an LS handle?? Is their like a formula of some sort to determine an estimated boost level or pressure level per point of rod ratio. This is a very important question in my mind because now I am reboosting my teg and when I redid my bottom end I was running low on funds and only had enough for pistons, so rods was where I sacrificed...

My setup is with JE forged 8.5:1 C/r but the rods are stock... Now I've seen some break/bend as low as 9 but others doing it on the track up to 20...! (On race day only with 107 leaded race gas) But my question still is, with JE/Forged pistons built for 25 psi of boost and stock LS rods and a newly built bottom end massaged and blue printed to exact specs what can I expect to run

A.) daily, but also
B.) On the track with 107 leaded...

Thanks for the help.

rod ratio is calculated by taking the connecting rod length and dividing it by the crankshaft's stroke.

A good rod ratio is considered to be 1.65-1.77. Some people say the ideal rod ratio is 1.75:1 or 1.77:1. Guess what? the Civic b16a 's rod ratio is 1.75:1 and the CTR b16b is 1.86:1. Co-incidence? I don't think so. Honda has lots of race engineering experience with high revs in it's Superbike and Formula 1 N/A engines...like 18,000+ rpm. They trickle this knowledge and tech down to us common folk in a street car...cool huh?

Unfortunately, the integras got a low or short rod ratio: b18b 1.54:1 and B18C 1.59:1...not ideal.

So what is the importance of rod ratio anyway?

rod ratio describes piston geometry (3 things):

1. piston speed away from TDC and BDC
2. piston dwell time at TDC
3. the amount piston sideloading against the cylinder wall as the piston travels up and down the swept volume.

So rod ratio can affect how high you can rev, since a low rod ratio places more side loads on the wall.

The rod ratio in a naturally aspirated engine affects how well the cylinder is filled and dictates cylinder head port size. The faster the piston pulls away from TDC on the intake stroke means you can get more suck to fill the cylinder. How fast the piston transitions or flip-flops from squeezing the exhaust gas out at TDC for the exhaust stroke to dropping down and begin filling on the intake stroke (i.e. TDC dwell time) affects your cam overlap and cylinder filling.

low rod ratio engines have short piston dwell times at TDC and fast piston speeds away from TDC (or faster piston speed dropping down on the intake stroke compared to a long rod ratio). So a low rod ratio motor generates high flow velocities for filling through the intake port at low-mid rpm. These engines like bigger cylinder head intake port sizes compared to a long rod ratio motor like the Civic Si's b16a.

Low or short rod ratio ALL MOTOR engines like a cam with more lobe separation angle, more duration, and more cam overlap, since it has short piston dwell time at TDC and needs help scavenging in fresh air/fuel.

This all has to do with revving ability, proper intake port sizing, and cylinder filling IN AN ALL MOTOR SETUP which depends on passive filling using lower pressure in the cylinder (called pressure gradient) compared to the atmospheric pressure (14.7 psi). In turbos and SC's, you push in the air to fill the cylinder and so rod ratio plays a very MINOR role in cylinder filling.

The importance of rod ratio in a boosted engine relates to how efficiently the inert burnt exhaust gases are removed from the cylinder after combustion. The piston speed away from BDC to push the exhaust gas out is important. Remember exhaust gases aren't burnt twice and cannot make power and so if they aren't removed, they just take up space in the cylinder ... preventing room for fresh air/fuel from coming in to do their job. Burnt exhaust gases are like unwanted tenants not paying rent: you want to evict them from the cylinder.

Short piston dwell time at TDC is less important in a boosted engine because you don't want big cam overlap. More cam overlap here would cause some of the boost to shoot over into the turbo manifold instead of going into the combustion chamber (assuming the boost pressure is higher than the exhaust manifold pressure). You don't need big overlap cams to help filling. In fact, boosted engines prefer big lift but short duration and overlap.

So a low rod ratio actually helps a boosted engine, since the piston speed away from BDC is higher than in a long rod ratio engine (to help evacuate the extra burnt exhaust gases) and the importance of dwell time on filling and cam selection is less important for filling.

JUST REMEMBER: don't rev the sh*t out of a low rod ratio engine (all motor or boosted)...the shorter rod ratio still causes the piston to sideload the cylinder wall harder causing more risk of a piston going through a wall, the higher the rpms go (keep it under 8100 rpm).

If you want to read more on rod ratio, check this site out:

http://victorylibrary.com/tech/crod-c.htm


quote: Originally posted by daNattyFatty

....but ls/vtec engines tend to put out more hp and torque than a
regular vtec engine. it makes for a good all motor set up

the LS bottom end has a lower rod ratio than the GSR or ITR bottom end.

as the rod ratio on a naturally aspirated (i.e. No Boost) engine becomes lower or shorter, low-mid rpm hauling power increases.

you see the peak torque shift to a lower and lower rpm, as the rod ratio drops. This is probably why Honda chose a shorter rod ratio with a higher displacement on the integras compared to the civics.

As you decrease displacement to 1.6L on a civic , peak torque , as an absolute value, becomes smaller and you have to rely upon higher rpms to generate horsepower, instead of depending on torque. So the civic gets a longer rod ratio because of where it's powerband will be located (in the higher rpms).

The 1.8L , with more displacement, makes more torque and has a lower "hauling" or "pulling" powerband. It gets a lower rod ratio.

Please be careful about making statements about the 1.8L LS VTEC peak torque compared to the 1.8L VTEC peak torque. You hear this statement that the 1.8L LS VTEC makes more torque (assuming the same cams , redline, header/ cat/exhaust, and static compression ratio in both engines). In most cases, unlike this myth of more torque in an LSVTEC, the B18C actually makes as much or more peak torque..BUT AT A HIGHER RPM: it's rod ratio is higher or longer than the LS VTEC's. The key here is: the VTEC engine with a better rod ratio can happily rev all day at a higher rpm than the LS VTEC over the years. You can push a stock B18C bottom end to 9000 rpm as long as the valvesprings are upgraded. You can't go to 9000 rpm on a stock LS block's rod ratio.

quote:Originally posted by Pollux

I know you probably hate repeating yourself Tuan, but thanks for all the help, I think we also covered some good things and those links were great!


Yes. It's a bit tedious saying things again and again but I hope that if I say it in different ways, more people can understand these basics. It's great to see when the light comes on for someone who never knew this before and they get it. It's great to see them then pass that info on to someone else...all in the name of building a better faster car for yourself...which was why we love this hobby: we're speed junkies.

This thread hints at some other concepts like the idea of engine package or engine combination. It hints at parts affecting powerband location.

I milk the idea of package over and over to beginners. A low rod ratio motor likes a certain intake manifold runner length / diameter , intake port shape and size in headporting, cam spec, header length/diameter, exhaust diameter. A short rod ratio motor likes a totally different set of parts with different design characteristics. And with these packages, the powerband (which is about 2000-3000 rpm in width if you are a good tuner) can be moved up or down the rpm range to your liking. Where it is placed dictates your tranny gear ratios. The narrower and peakier the powerband, the more gears you will need. You want your shifts to fall to an rpm just below peak torque to get the most acceleration.

It all ties together. Buying a part without overseeing how it fits in the whole thing makes for a disappointing result both at the dyno and more importantly, at the track...it's a lousy feeling not getting what you expected based on how much you worked hard for, saved, and spent...all because you don't understand engine package, powerband locating, and gearing. Trust me, I've been there. I eventually learned from pretty smart generous people. Hope this helps you guys think it through better and avoid the future letdowns.

As far as costs go, converting an LS to an LS VTEC can vary from $2000 to $10,000: the bare basics with a stock LS block and no change in the bottom end internals will run you $2500 for the head (legitimately obtained and not stolen of course), machine prepping of the head ducts and dowel pin alignment, VTEC ECU & wiring harness, and proper install. Some people, like importbuilders.com for instance, charge as much as $8000 for the whole shabang with a lot more upgrading on the cams,valvetrain/cam gear, and bottom end.

As I said, most people move the CR up and keep the revs at 8000 rpm max. Please look at Chris' dyno above again. In an LS VTEC with an 11:1 CR and ITR cams: over 185 whp and a well-tuned flat torque curve from 6000-7500 rpm sitting at peak torque for that powerband (6000-7500 rpm)...and a nice safe 8000 rpm redline. That's all you need to run low 14's-high 13's et (assuming decent tires, engine mounts, and springs), all day, every day without going kaboom IMHO. If you want more than this by having 11.8-12:1 CR and cams with 12-12.5mm lift, 255-260 duration in an all motor setup, that's your business.

I suggest at least talking to people like drtracing.com or c-speedracing.com for their advice and experience , if you are thinking of doing this. They don't charge $8000-$10,000 for an LS VTEC build up.The oil/coolant leak thing and lower revs than a VTEC block are huge issues to remember for the LS VTEC reliability.

cheers
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Yo my bad if this is illegal or if some people get offended or something but just trying to help it is a good read. dont lock this thread i dont want to mess it up for this guy give me an im if you want me to delete it.


Modified by zad5 at 9:57 PM 5/12/2003

2lowintegra

^ wow, nice write up

0F1Spec

this happened to my friend before.

he tapped the head wrong so it's leaking oil slowly from the headgasket.

rodrez.

Hit up HT member "Manyfaces", he ran LS/VTEC with ITR pistons for almost 3 years, took it past 8k very often, ran very strong.

arw321

I think for a RELATIVELY safe LS/VTEC bottom end you need the following:

ARP Rod bolts
Shotpeened rods or new forged or billet rods.
BALANCED ROTATING ***'Y.

StyleTEG

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by JayDM.com &raquo;</TD></TR><TR><TD CLASS="quote">well my basic outlook on it is:
LS bottum end = low flow
VTEC heads= high flow.
</TD></TR></TABLE>

uhhh.. the LS block has more displacement, so technically its higher flow. Which is why people match the LS/B20 block with a Vtec head.

GZR4DR

I've had my B20-vtec for quite a while now. I'd say around 2 years. I have put over 30K miles on it already and it runs like a champ. For starters, I recommend getting a vtec oil pump. Fortunately the B20 block already comes with one. Block the oil feed hole in the head, run the oil line from the block to the head, and you should be fine. This is for street driven 8K redline. If you want to rev past this, you will need to do a few more modifications. ARP rod bolts, Z-10 crank girdle, oil sprayers for the pistons, and you can rev higher safely.

On one of my previous GSR motors I dropped a valve and blew it up. You can do the same exact thing on Ls-vtec's however you can't blame the block. Any motor can blow up if you rev to high, or don't build it right. So many factors of things that can go wrong.

If built right, it wont leak any oil at all, you can rev to 8K just fine, and the motor will run strong. I highly recommend going the B20 route for the extra displacement and also the higher flow oil pump. B20 motors also come with a spot for the knock sensor. B20Z's include a knock sensor. Just so you know, a stock B20-vtec isn't exactly fast, it will need mods just like any other honda motor to have better driveability.

granada_sun

how do u get oil sprayers machined into ls block???

Mr. Softee

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by JayDM.com &raquo;</TD></TR><TR><TD CLASS="quote">well my basic outlook on it is:
LS bottum end = low flow
VTEC heads= high flow.
if it was math it would still add up to be negative!
and if youve ever taken a VTEC bottum end apart you will see how much VTEC complaint parts are in the block... VTEC is all about oil pressure!</TD></TR></TABLE>

wtf are you talking about

Mr. Softee

rod stroke ratio is all bullshit.

oil squirters arent even needed w/ forged pistons.

the problems are poorly teed blocks, poorly tapped heads, rod bolt stretch (ls rod bolts are like D series ones), which causes rod failure at high rpm.

an ls/vtec with forged rods/pistons, properlly tpaped using the GE oil adapter, will be a badass mother.

personally id rather run an LS crank w/ ls spec rods in a GSR motor, the extra displacement is worth it, and rod/stroke ratio is about as overhyped as going all motor in the first place.

granada_sun

spoken like a true FI junkie....hehe

.....so whats a GE oil adapter??

Calavera

^^^ shitload of reading, but worth it.

granada_sun

and why wouldnt forged pistons need oil squirters any less than regular pistons??