David,
the L18 valves are 42mm intake, 33mm exhaust across the board. There may be
later ( and rarer ) heads with larger exhaust valves, but I can't say for
sure. Late issue L16 heads have the same valve sizes, early L16s had 38mm
intakes.
The SSS heads of both L16 and L18 ilk have larger intake ports - 38mm round
instead of about 33mm. This improves top-end breathing significantly but
loses driveability and torque to some extent. I have found heaps of
'L18SSS' motors with the small ports though, either because of replacement
or perhaps Oz-delivered L18SSS motors didn't get the 'good' heads.
Removing the intake manifold will reveal all - don't fork over any $ until
you're sure it's the real deal, and better off having the head in your
hands first so you can check the thickness ( too many skims = useless ) and
gasket surface for corrosion.
If you're serious about it, you can take most L-series heads with the
peanut-shaped chambers and modify it to better-than-SSS spec by opening up
the intake ports ( not hard, but hard to do right ) and installing early
L28 intake valves ( 44mm ). You can also install bigger exhaust valves if
you're after all-out power, if you can find a machine shop of sufficient
confidence and competence.
No argument with the Weber / SU statements. Sidedraft ( DCOE ) Webers
better power but SU's better economy / driveability - more set'n'forget
than the Webers.
240hp L18 ? Scan that dyno readout for us will you ? ;)
Seeya,
DF
PS - woohoo, an L-series Q !!
At 23:04 26/03/00 +0930, you wrote:
>i was chatting ot a guy last night and he is a bit of a wiz on the l series
>motors, used to rally a 1600. He told me that the 180b sss head has bigger
>values or something?, is this write anbd would it have a desent inprovement
>on the standard 1800 i have on my l20 now?. Also he told me the webers have
>no bottom end and if i use good su's they will be better?. I would like to
>talk to some people that have done up l series motor and know all the
>tricks. The guy i was talking to got 240 hp out of a L18, is this good?
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