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RE: Z20 motors

To: "'Roadster List'" <datsun-roadsters@autox.team.net>
Subject: RE: Z20 motors
From: "Mitch Planck" <mitch@ias.net>
Date: Mon, 13 Nov 2000 10:57:21 -0500
Interesting. I've got a KA-24 in my Stanza. It's a 12 valve, transverse
mounted FWD, so unless there was a RWD model, I'm thinking this would be a
difficult conversion. I do like the engine though. It's my daily driver,
still very strong after 180,000 miles. I can squeak the tires in second
since I replaced the clutch about 50,000 miles ago. 146HP in a 3000lb car
with 185/70s.

I also noticed something else interesting about this car - the tach/speedo
gearing seem to match my Roadster very closely, except for 5th gear, since
I've got the 4-speed tranny. In other words, if I'm going 4000rpm in 2nd in
the Roadster, it's the same speed as 4000rpm in the Stanza. Since I doubt
the tranny and rear-end are geared the same and they have different size
tires, it seems to be an interesting coincidence. It does make some sense
though since they are probably good gearing combos to keep the torque/power
curves maximized.

-Mitch
'69 1600
Chelsea, MI
http://beladi.stormloader.com

-----Original Message-----
From: owner-datsun-roadsters@autox.team.net
[mailto:owner-datsun-roadsters@autox.team.net]On Behalf Of Ronnie Day
Sent: Friday, November 10, 2000 6:04 PM
To: Roadster List
Subject: Z20 motors


I must have deleted the original message asking about a Z20 in an
SPL/SRL. Then again I may have dreamed it all, but here goes since no one
else jumped in. The Z-20 was pretty much a slight modification of the
L-series block on which Nissan dropped the NAP-Z head. Even though this
was a crossflow head there are a number of reasons it was never
performance developed like the R, U and L series top ends. It's pretty
simple to adapt an L-series head to the Z-block and that combo has been
popular as the basis for building 2200 and 2300 cc L-series motors. The
Z-20 block are reportedly stiffer and have more cylinder wall material
that the L-20, but the L-20 is probably more common.

The Z-series also came as the Z-22 and Z-24. Deck height on the Z-20 and
Z-22 are the same, but the Z-24 is about 3/4 inch taller than the L-20
and Z-20/22, which were already 3/4 inch taller than the L-16/18. In
other words, if you want to use an L-head on the Z-20/22 you can use an
L-20b timing chain, but there is no off the shelf OEM or aftermarket
chain the the Z-24/L-head combo. You have to cobble one up on your own.
Folks who've tried this have had widely varying degrees of success. With
an L-series being a tight fit already, the taller Z-24 could be a real
challenge in a roadster and there are better alternatives, IMHO.

The Z-motors use basically the same motor mounts and such as the L-series
but mount the engine at a different angle so you'd want to get a Z-series
trans, too, or have to fabricate an adapter for either the roadster or
L-series trannies. A follow-on to the Z-series swap is the KA-24, more
often with the 12 valve since that's how it was imported in the US,
AFAIK. Bill Kenyon can be more definitive on that and comment on how the
KA works in a roadster since he has one. It really scoots and I imagine
is a lot of fun to drive hard or more calmly since I'm sure the KA has an
abundance of torque compared to the R motor, somewhat less to the U-20.
Most of the KA powered street cars I've seen, Roadsters and 510's have
EFI which help driveabililty a lot I'd guess. Dropping any of the L, Z or
KA motors in a roadster is going to require quite a bit of fabrication.
At least motor mounts, oil pan, exhaust, maybe some steering linkage.
Doable, but far from a bolt-in.

FWIW, Ron

Ronnie Day
ronday@home.com
Dallas/Ft. Worth
'71 510 2-dr (Prepared Class Autocrosser)
'73 510 2-dr (Street Toy)

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