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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