KZ vs NF, Overbore

Richard Hoffman billzcat1 at
Thu Nov 15 10:22:28 EST 2001

Oh BTW these oil-squirters...where are those located?  I've never been quite
sure about that although I've heard of that on many of the higher-quality
turbo cars.  I know it sprays the bottom of the pistons with oil to cool
them...but where are they, how do they work?

1990 CQ 193K
----- Original Message -----
From: <JShadzi at>
To: <billzcat1 at>
Sent: Thursday, November 15, 2001 6:36 AM
Subject: Re: KZ vs NF, Overbore

> And don't forget the oil squirters, it won't have those, but they can be
> added, but that starts driving up the cost quite a bit instead of simply
> finding an NF/NG block.  Also, the KZ is machined differently wrt the way
> AC bracketry bolts up, the NF using the spot where the MC has the turbo
> return line.
> Any of the I5 blocks can easily be bored to 83+mm without any problems.
> with up to 84mm, but that is pushing the block and head gasket surface to
> max.
> There is nothing that makes the NF different from the KZ in regards to
> size and cylinder walll thickness, they are identical in that respect, one
> just has had a bigger bore cut out of it.
> Javad
> In a message dated 11/14/2001 11:59:12 PM Pacific Standard Time,
> billzcat1 at writes:
> << In the never-ending quest for knowledge and hp....
>  The main difference between the KZ block and NF block is the bore - KZ
>  smaller at 81.0mm, NF at 82.5mm.
>  What is the maximum overbore a KZ block can take?  Factory lists oversize
>  pistons up to 81.5mm but I was wondering if they could be bored up to
>  to essentially turn it into an NF block.  And then, maybe 83.0mm, the
>  factory-spec oversized (2+) pistons.
>  I was thinking that the cylinder walls would be thickest on the KZ when
>  was stock - then you could bore it up to the NF size for a little more
>  displacement and still have a decent wall in there.
>  I'm sure there are tons of you out there who have had their KZ apart and
>  could probably tell if the block could take 1.5mm overbore.
>  Thanks!
>  Richard
>  1990 CQ 193K
>   >>

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