xr2wishy

iTrader: (2)

having a little dilema so to speak of.
basically it's not an rs, but couldn't think of which section to put this in so here goes.
i'm about to order my rods/pistons and bearings from the states and if i go for standard bore of 85mm the items will be shipped this week, if i go for the oversized ones then it'll be 5-6 weeks.
then there is the boring of the block which is only a couple of days turn around, extra cost is only about £100 for the extra capacity.

i'm just after someone saying what is the better option as i've heard that the zetec cylinder walls are already thin without the boring, i'm happy to wait if there is a genuine advantage i'd kick myself over at a later date.

cheers
sean

p.s. put on focus section, but probably more suited here after using my noggin.

Sp3no

iTrader: (1)

How many miles has the block done? You need to measure the bored as they may be worn and require an overbore anyway.

xr2wishy

iTrader: (2)

not certain on mileage (approx 60k), still see honing marks clearly though.
i'll have a quick measure..

xr2wishy

iTrader: (2)

84.78mm on all cylinders

Sp3no

iTrader: (1)

I would definately check the bores are within limit and allow for the tolerances of forged pistons which are a bit tighter. I personally would rebore to the next size when fitting new pistons into anything but a brand new block.
The extra capacity will see a good amount of extra tourqe.

Find out the required piston to bore tolerance and relate it to what you just measured

xr2wishy

iTrader: (2)

the tolerence would be around 0.07"
so would be ok, bearing in mind the bore is already smaller than 85mm, not taking in account of honing losses
it's more of a question of the bore walls being too thin, or would it be a waste to not put the bigger pistons in as i'm getting new parts anyway.

xr2wishy

iTrader: (2)

anyone any opinions that has built a ZT?