Now that is real interesting. I'd personally love it if you'd elaborate a bit
on your setup, especially the manifold.
Here in the US the single ZS has a very bad reputation...but, I suspect the
problem is the manifold. There were two different sized runners. The earlier
manifold had large cylinder runners, and the later manifold had very small
runners. I don't know the year the change took place. Part of the reason I
suspect the manifold is the problem is that some folks with ZS on early models
don't complain about the horrible lack of power, especially high up in the rpms,
that so many folks complain about (I was one of them, that's why I switched to
dual HS2's.).
It wasn't until after I'd gone through the conversion that I learned about there
being two distinctly different manifolds. I did locate an early one recently
with the large runners, and took it home. Perhaps I should use it and a single
HS6. For like you say, it's a whole lot easier to set up.
So please, tell me/us more!
Nolan
P.S. My overboard crankcase vent is not in a low pressure spot. Though I'm
surprised to hear of the Spitfire sucking oil out that way. I'd have thought
the head to be well drained, and very lightly supplied with oil to suck out.
I'd like to convert the engine to true fresh air pcv some time, but I probably
never will.
John Kipping wrote:
> There is surprisingly little difference in performance, in actual fact tests
> have shown that an engine with a single HS4 has the same power as twin HS4s
> up to 4500 RPM, and of course the torque is not affected. Personally I use a
> single HS6 as it is easier.
> John Kipping
/// spitfires@autox.team.net mailing list
/// or try http://www.team.net/cgi-bin/majorcool
|