Re: Euro cams

["John E. Newhagen" <newhagen@domain.elided>]

If your state's pollution police will let you get away with it, this is 
a definite go.
I too have a '73 and did the switch last year. The car had Webers on it 
when I
bought it, which was fine, but four things bothered me:

- uneven idle
- soft spots in the power curve
- overall hp
- lack of purity

 The change helped all four, I have a much smoother idle now, much 
stronger performance at low an high rpm,
it just goes better, and I am pure.
 I did it in conjunction with an in-car rebuild and strongly suggest 
that as a tactic because you can do other upgrades in conjunction with 
the cams -- including stepping to slightly higher compression pistons 
and installing a true Euro manifold and headers. You can use piston 
liner kits for 1980's spiders and they work just fine. I had a hell of a 
time finding the manifold and cams, I finally went to a very helpful 
dismantler in Australia (let me know if you want his email.) (BTW 
Defatta in Baltimore may
have stumbled into a cache of brand new Euro cams when it bought out the 
inventory of a Norwegian dealership a
while back.) The manifold solves the problem of air leaks with the 
0-rings on the aftermarket conversion kits. That may solve rough idling, 
plus the installation just look more elegant. After market headers are 
available everywhere. I kind of wish
I had not gone to the ANSA exhaust, which eliminate the center silencer. 
It may reduce back pressure, but it is frankly
just too loud.

Jets can be a problem. My mechanic deferred to me to get them right 
just because it is easy to do but they can be hard to find.
He gave me a chart of the exact set used in the Euros. There are a 
couple good sources for jets but the problem is
that one (I think the emulsion tube) is no longer in production, so you 
have to approximate. If you need the exact
specs, let me know.
As for what the cams do technically, my understanding is that they are 
not really higher lift, it is just that the
exhaust-intake overlap is a bit longer. What that does is to keep the 
exhaust value open a bit longer while the
intake value is opening. This tends to suck more fuel in to the 
combustion chamber faster. It solves the
problem I always had with the Spica cams of running too lean or too rich 
and not being able to compensate by carb tuning.
The reason they quit doing it is the grind also has the side effect of 
dumping more raw fuel into the exhaust output
which is an environmental no no. I like this solution for street use 
because it does not increase lift. When I was
much younger I made the mistake of putting high lift cams in a '67 Lotus 
Elan. It ran real nice at 7,000 rpm,
but idled like a cement mixer.

So the bottom line is that I can say I am pure, and am running a true 
Euro '73, and it runs really nice.

--
John 
'73 Spider
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