I quote myself here...
<< Now
we get to the tough part...according to my memory banks,( now wait...what is
it that goes first ? I forget...<g>) >>
Well that just goes to show, I really have lost my, my ah, you know
whatchamacallit !
I incorrectly remembered that the cylinder heads were given the chamfer at
the squish area edge, when they went to the "high port" head. As I didn't
think we were dealing with any heads that are that old, I skipped talking
about them. However, when you said that you had more than one of the heads
without the chamfer, I had to go for emperical evidence.
So, off to the shop for an informal experiment. Here are the results of a
very unscientific experiment, based upon insignificant numbers of examples.
Two of three large port TR3 heads did NOT have the chamfer (the one that did
looked as though it could have been added later). All of the small port TR4
&4A heads DID have the chamfer. All of the late heads I could find were the
very late ones with the "tulip" style exhaust valves.
So, given these examples, I would feel safe saying that the chamfer was added
later in the production run, sometime after the TR3 series of heads, but I
can not say whether the early TR4, small port, non-tulip shaped valve heads,
had the chamfer.
Anybody else have a head they can survey to add to the polled base ?
According to Kastner, the chamfer was added to reduce the area of metal that
would absorb heat from the combustion. (Hot spot in the head ?)
Sorry for the misinformation...guess the ole gray matter ain't what it used
to be
Nick in Nor Cal
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