My 87 Accord had iron liners, but that design ended in the early
1990's. There's some magic process they do that chemically forms a
silicon-composite coating on the cylinder walls, and I think the S2000
uses a different alloy that forms a better coating, but unless I've
misunderstood for a long time, the iron liners are long gone, along
with carbuerators and mechanical distributors. Next to go: camshafts.
the silicon relief etching is what was tried on the porsche. it worked
fine in the lab, but was not good in practice.
the honda solution is to cast a thin iron liner into the block. it's
only a few mm. go to a junk yard and check out the motors that have had
their heads pulled. the outside of the wet liners are indeed alloy from
the casting, but scrape the top face, and you'll see the change in color
between the two materials - the interior is most definitely iron.
it's a carbon matrix liner, and it too is cast into the alloy block.
iron liners are very much alive. there's nothing to touch iron for wear
and heat transfer at that price point.
camshafts will be with us for a while longer. there's plenty of other
actuation devices which theoretically could offer significant
advantages, but it's hard to replicate the "gradual opening" effect of a
cam driven valve - and that has substantial gas flow benefit - without
spending a good chunk of change. different valve operation would offer
the "holy grail" of truly variable valve timing, but let's be realistic,
there's no way a manufacturer is going to substitute 100+ year
reliability that costs maybe $100 for the whole shooting match in
quantity, with something that's going to cost $1,000+ which for most
applications, offers no benefit. even F1 doesn't have engines haven't
abandoned cams, and if there is a bottomless money pit into which
engineering initiative is dropped, it is F1.
I will swear that some car magazine said Honda was using this on their
mainline engines at some point around ten years ago. Maybe it came
But Googling around ... seems to show you are correct about now.
Well hey, maybe I misunderstood whatever back when. Glad to hear it,
actually, never did think anyone had the technology to do without it
and deliver real realiability.
So, well, thanks!
car mags publish crap, with a lot of the import scare stories being
"inspired" by detroit in an effort to keep the home fires burning.
kinda scary actually. kinda ironic too seeing as nowadays, detroit's
falling over itself to source so much of its componentry from china.
there's other solutions out there including hard chrome lined aluminum
[used in some types of applications like powered hang gliders iirc], but
at the end of the day, it all comes down to durability for the
application - and price. right now, iron alloy liners are king and are
likely to remain so for the foreseeable future.
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