lo guys.

quick question for you. what is the max safe overbore i can go on stock b18c4 sleeves?

i just picked up an engine for cheap (it dropped 2 valves and holed a piston) ripped it right down and the crank etc etc looks good (no scoring or spun bearings etc)
cylinder 4 that dropped the valve has marked the sleeve wall. i got some clay out and pushed it into the bore to see how far in it was dented/marked. looks to be 0.40mm deep.

manual states 81.5mm is the max limit, could i go as far out as 82mm if needed?

planning on running 9.5.1 forged pistons with eagle rods on a b16a head at around 8-10 psi (would be happy with 300 flywheel ponies and some nice torque)

cheers!

 

.5 for stock sleeves

 

For a boosted application, the largest you can go is 81.5mm on stock sleeves. You CAN go 82mm but with a turbo setup, you're liable to crack a cylinder wall. If you were building an NA setup, you could go 82mm...

 

82mm is even pushing it for NA

 

ok thanks.

really ought to measure the wall and see how far in the dents are. there are only one or two deep ones so lets hope a 0.5mm can remove them

failing that i guess i shall have to re-sleeve the engine

 

hmmm i think i am not going to be ok on this.

for 0.5mm oversize that's 0.25mm from the total wall thickness right? (i reacon some of these dents are 0.30-0.40 deep into the wall)

worst case scenario, i either fit darton mid sleeves over here in the uk (if i can find someone to do it) or i have a b16a block sat here, but its crankless etc.

is it possible to fit the 87.5mm crank from my b18c4 (same crank as the type r) and run either a custom rod to give me my target 9.5.1 compression ratio? do eagle make custom length rods?

 

You can do .020" over stock 81mm bore which would put you at 81.5mm

.25mm is .010"

 

Jg states 83mm on their max stock sleeve engines

 

right i got some clay today and shoved it into the walls to get an imprint of the dents.

i think the deepest is around 0.20mm, so that 0.25mm hone/bore to take 81.5mm pistons should be ok :D (i have a digital tyre dept gauge with reads to 2 decimal points so i pulled it out 0.25mm and used that as a guide)

thanks for the advise. just need to build this up and hope this nasty b20 vtec engine i have holds together until its ready to go in :lol: