I currently have a LS motor that needs a rebuild in a EJ coupe. Been wanting boost(turbo) after having my SC b16 hatch i had to sell. One of my good buddies who does alot of my work suggested to bore the LS to 84mm standard rebuild and just throw a Greddy Turbo kit with 6-8 lbs. Stock LS bottom end with bore/hone 84mm, rebuilt lower blah blah. Stock LS rods but with new B20z pistons. The head will be ported with the valve job from comptech. New ARP rod bolts and other misc stuff.

Sounds like a good plan Right??? Now that you have the gist of the story.......
1.Has ne 1 done this type of setup??
2.Are the cyclinder walls stable for boost with out sleeving? Planning to run 6lbs
daily and 8 for racing. maybe more???
3.How much boost have you run on this set up before KAaaaboom???
4.How reliable is the setup compared to a stock b20 turbo setup????

 

you CANNOT bore a B18 to 84mm....... period.

you need it re-sleeved......OR find a B20.

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by non-VTEC &raquo;</TD></TR><TR><TD CLASS="quote">you CANNOT bore a B18 to 84mm....... period.

you need it re-sleeved......OR find a B20.</TD></TR></TABLE>

...huh? You sure?

 

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

...huh? You sure?</TD></TR></TABLE>

yes

 

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

yes</TD></TR></TABLE>

It is not possible and if it is then get ready to spend money on another motor.

 

edit read it wrong

 

If I re-sleeve the block and do what you say, will it pass smog?? basically im trying to make it a visually legal (B18 block) with B20Z 84mm pistons and still pass smog and whoop some *** with a 2.0L.

 

passing smog is up to your engine tune.....visually it will look like a B18 engine even though its now 2.0L.........but you need to make sure the tune is good enough to pass the test.


but i would like to add a little advise.......if you are serious about re-sleeving your engine please don't run stock B20 pistons...that would pretty much be a waste of time/effort.....a good set of aftermarket forged pistons are not that expensive and will take much more abuse/power.

 

Thanks for the advise. I was hoping not to re-sleeve. thats y i went with the stock b20z pistons. But since i would have to sleeve im not going to do it half assed. I would do rods and pistons. since the LS doesnt have a block girdle like the gsr block. should i put the gsr girdle on there even though im not going to rev past 7500. or am i wasting time and money. Also how much is safe boost limits with a sleeved LS 84mm. This is my daily driver.

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by non-VTEC &raquo;</TD></TR><TR><TD CLASS="quote">you CANNOT bore a B18 to 84mm....... period.

you need it re-sleeved......OR find a B20.</TD></TR></TABLE>

WHY? From what I have been told, and i dont see why it's not true, but isn't a B20 just an 84mm bore LS motor?

 

the cylinder walls will be way to thin if there is any left after its punched out to 84. Thats why you need the sleeves.

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by Turbo_TONY &raquo;</TD></TR><TR><TD CLASS="quote">the cylinder walls will be way to thin if there is any left after its punched out to 84. Thats why you need the sleeves. </TD></TR></TABLE>

SO what ur saying is that the sleeves on a b20 are thicker?

 

a b20 is not just a Ls bored out to 84. It is designed for 84mm. The Ls is designed for 81mm...so when you start taking away material from the cylinder walls, it makes them thinner and wont be able to to take any abuse..hence the sleeving puts the strength back into the cylinder walls.

Thats how it works out in my head atleast..lol. did that makes sense?

 

Let's say we re-sleeve both the b20 and the b18. Will we run into the exact same bore-limits and standards there? Meaning...they'd be the same thing right?

so...this would mean that the stock b18 sleeves aren't really that thick, and they have room ---&gt; could be much thicker. While the b20 sleeves are probably thinner, they still are comparable to the b18 sleeves (thickness) ?

 

ok see the flaw in the logic here is that even though the sleeves are different bores the iron liner is roughly the same thickness at 81mm and 84mm for the different engines. So if you take an 81mm sleeve and bore it out to 84 there is going to be very little iron liner left before you get to the aluminum portion making it very weak. Now the b20 sleeves have slightly thinner iron sleeves than the b18's do at 81mm, hence why you hear about them cracking alot (under heavy load of course). To accomodate the larger bore the aluminum outside liner is thinner and not the iron portion which is what has the actual strength.

Did that make sense?

Edit: here i made a picture


You can see where the iron liner is and the aluminum portion, if you look the iron liner on both is roughly the same thickness while on the b20 sleeve because the bore is larger and the iron liner remains the same thickness it require that the aluminum portionmust be thinner to fit in the constraints of a b-series block coolant passages. If you bore out the b18 the bore will then be the 83 but there wont be any iron liner. i hope this helps


Modified by Soccerking3000 at 11:30 PM 4/8/2006

 

^^^awesome picture/explanation

 

much better than mine...this is why i dont teach

 

are the outside circles the same in that picture?? thats a good optical illusion. i love it.

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by Spec R &raquo;</TD></TR><TR><TD CLASS="quote">are the outside circles the same in that picture?? thats a good optical illusion. i love it.</TD></TR></TABLE>

yea the outside circles are the same size (the aluminum portion of the sleeves)

 

IMO its not worth resleeving the block without a descent forged pistons and rods combo...cause later on you will be wanting to boost more save yourself the downtime later on the road...but its your setup...

passing smog shouldn't be a problem...as long as you have a good cat thats not burnt out and is it going to be tune or...running the blue box...what mangement are you running..if tune on injectors of such as long as the tune conservative it should pass smog easily

 

bump

 

Here are your options. Boost the LS like it is stock, get forged rods/pistons and boost it, or get aftermarket sleeves and bore it to 84mm. End of thread.

B20 sleeves are actually thicker than B18 sleeves by the way, they are designed completely different and much weaker than B18 sleeves also.

 

up

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by SILENTJ95670 &raquo;</TD></TR><TR><TD CLASS="quote">up
</TD></TR></TABLE>

up for what? everyone answered your questions.......take some time to read and search.......

someone should lock this post......

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by Soccerking3000 &raquo;</TD></TR><TR><TD CLASS="quote">ok see the flaw in the logic here is that even though the sleeves are different bores the iron liner is roughly the same thickness at 81mm and 84mm for the different engines. So if you take an 81mm sleeve and bore it out to 84 there is going to be very little iron liner left before you get to the aluminum portion making it very weak. Now the b20 sleeves have slightly thinner iron sleeves than the b18's do at 81mm, hence why you hear about them cracking alot (under heavy load of course). To accomodate the larger bore the aluminum outside liner is thinner and not the iron portion which is what has the actual strength.

Did that make sense?

Edit: here i made a picture


You can see where the iron liner is and the aluminum portion, if you look the iron liner on both is roughly the same thickness while on the b20 sleeve because the bore is larger and the iron liner remains the same thickness it require that the aluminum portionmust be thinner to fit in the constraints of a b-series block coolant passages. If you bore out the b18 the bore will then be the 83 but there wont be any iron liner. i hope this helps


Modified by Soccerking3000 at 11:30 PM 4/8/2006</TD></TR></TABLE>

that picture is misleading, the actual iron liners of the b20 sleeves are connected between the cylinders instead of having a FULL aluminum jacket around them as the b18 blocks do.