i just bought a brand new freshly built bottom end.. and it is 84.5mm bore.. and i didnt have it sleeved.. its going to be street driven and races once in awile.. do you guys think it will be safe with me not sleeving it.. the hole build should push around 230hp.. hoping..

 

so its a b20 bore to 84.5? or a 1.8

 

b20 bore to 84.5

 

u shouldnt have a problem as long as you get it tuned properly, im starting my build next week

84.5 rs machine pistons 11.7.1 comp.
ported b16 head
revsprings and retainers
blox b cams
bdl gears
type r manifold

my buddy has a built b20 vtec for bout 2years and still runs strong as hell 237hp and 167tq.

good luck with ur build.

 

Whats safer, a 81mm block bored to 84.5 or a b20 block bored to 84.5?

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by pgpbubble &raquo;</TD></TR><TR><TD CLASS="quote">Whats safer, a 81mm block bored to 84.5 or a b20 block bored to 84.5?</TD></TR></TABLE>

holy crap are you kidding me... an LS block with stock sleeves bored to 84.5!!!! damn i don't even think thats possible. you will have a peice of paper for a sleeve!!

the B20 block is already 84 bore. i've gone 84.5 with no problems on a few all motor builds.

impossible on the 81 bore.. very possible on the B20 block.

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by pgpbubble &raquo;</TD></TR><TR><TD CLASS="quote">Whats safer, a 81mm block bored to 84.5 or a b20 block bored to 84.5?</TD></TR></TABLE> you can not bore a unsleeved 81mm block to 84.5mm you can bore a b20 to 84.5mm but i only sagest for all motor. if nos or turbo i don't sagest using a b20 unless your sleeving it and yes i know guys do it but most of the time they crack the sleeve and ruin there new pistons.

 

I built a B20 for a customer about a year ago. 84.5mm. 11.5 compression, naturally aspirated. Ran good. But then he decided to spray it, and cracked the sleeve the first time he sprayed the motor. I am not sure how much nitrous he sprayed, but he cracked sleeve, and messed up the brand new weisco pistons that were in the motor.

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by Power Rev Racing &raquo;</TD></TR><TR><TD CLASS="quote">I built a B20 for a customer about a year ago. 84.5mm. 11.5 compression, naturally aspirated. Ran good. But then he decided to spray it, and cracked the sleeve the first time he sprayed the motor. I am not sure how much nitrous he sprayed, but he cracked sleeve, and messed up the brand new weisco pistons that were in the motor.</TD></TR></TABLE>

yep seen that happen many times... nitrous motor b20 i just usually spray with the stock block. or on the RS pistons with stock 84 bore. seems to hold up okay.. squeezing over a 100 shot on it. those sleeves are VERY unforgiving however.. tuning has to be very good.

 

how much displacement exactly is a B18C1 sleeved with 85mm bore and a 87.2mm crank?

 

3.1416 x bore x bore x stroke / 1000

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by d15Beta &raquo;</TD></TR><TR><TD CLASS="quote">3.1416 x bore x bore x stroke / 1000</TD></TR></TABLE>

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by pgpbubble &raquo;</TD></TR><TR><TD CLASS="quote">Whats safer, a 81mm block bored to 84.5 or a b20 block bored to 84.5?</TD></TR></TABLE>
don't even think of it ...

 

85mm with a mild build seems to be holding up fine for me, I've got about 600 hard track miles and counting..........