Warning -- Whoever it was that bemoaned the lack of "tech stuff" on this list
a while back, this ought to satisfy them. Lotus minutiae ahead --
| all Europas with Twin Cams are Big Valve heads :-)
Well, yes and no. In 72 they put some leftover small-valve Weber heads on
European-spec Europas, but all the Federal-spec cars (ie, Stromberg heads) were
Big Valve. I'm told that there are actually 3 Weber heads for the TC, known (in
chronological order) as the "early Weber", the "late Weber" and the "Dellorto"
heads. with minor casting differences in things like cooling jackets, ports
and
such. They also changed alloys after the first one; the latter two are
somewhat
easier to weld. On the other hand, they are also a little more prone to
cracking
around the head bolts. Weber and Dellorto carbs are bolt-on interchangeable, of
course, the names just came about because the "Dellorto" head came out after
Lotus
switched to Dellortos and never came from the factory with Webers -- Dellortos
first
appeared on "late Weber" heads. All "Dellorto" heads were Big Valve, all
"early
Weber" were (originally) small valve, and "late Weber" heads were some of each.
Any of them can be modified for the larger valves, however. Even modified, the
Dellorto heads supposedly flow slightly better, but it's a tiny difference that
only a flow bench could detect.
| Other than that, regular valve heads can be converted to Big Valve
| heads by a machine shop that knows what they are doing (see below).
| The exhaust valves are only about 0.1 inch bigger in diameter or some
| relatively small change
That's the intake valves, and they're 1 mm larger. You also have to open up
the
ports a bit, though.
Dave Van Horn davevh@microsoft.com
|