Cylinder bore

[kizzyturbo4x4]

im building my new engine and had a thought about which pistons to get regarding bore i need/want

This engine had only covered 40-45t miles,
and it was like new when opened.
the sylinders has NO sign of any wear at all!
do i need to bore it up? or can i just stick with 86mm?
maybe its better just with 86,5 istead of 87 as i first planned?
if i can use the sylinders as they are i save money and i can rebore it again if things go wrong sometime in the future?
hows just doing a full measurment of the sylinders to check theyre ok?
and by the way i am after all gonna have 450bhp when all done.

any opinions/suggestions on this?

 

[ashills]

maximum u can bore the cylinders to is 87.5mm so u can either go 86.5mm or 87mm and know u are safe for another rebore later on if needed
if the bores are ok u could just hone them save on the cost of boring etc

 

[skiddusmarkus]

When you say there's no wear do you mean to the eye or by measuring it with the proper tool(whatever that's called :lol: ).They could be slightly oval and you'd not notice.

If you can get away with 86.5mm and you plan on maybe rebuilding in the future then go for it as you have the option of 87mm next time round.

 

[kizzyturbo4x4]

thats why i talk about measuring it, cause i cant se if it oval
so anyway i would do that before i use it.
used a 5mp camera and took close ups and there isnt any other marks then the one from original machining.
but if they check out allright, can i just rehone/repolish them and go 86mm?

 

[sypher]

stock bore is 86mm and 86mm stroke (square), to over bore IF required will need block removal and "rough bore the final hone" to desired size for specified pistons.

To measure bore "barrell and ovality" you will need a mercer / cylinder bore gauge, bear in mind it is necassary to measure to 0.00X of a mm as running clearance is 0.003 ( i think !!! ).

you can go straight to 87mm and if you ever need to rebore again you can get sleeves ( jun / hks ) which will allow for an even stronger block,but with cost

 

[Mr GTiR]

just go stright for 87mm pistons you get the added benefit of larger capacity and more torque when you up the boost 8)

 

[ki_saj_ng]

to get a rebore, it wouldnt cost u more than 150 so most preobably better to be on the safe side and as Andy has just said u would benefit from a larger capacity.

saj 8)