Subject: [alfa] what's the maximum RPM for Alfa engine

[RonHorowitz <RonHorowitz@xxxxxxxxxxxxxx>]

>What is the maximum RMP I can reach without risking to damage my 2L Alfa
>engine?

Deceptively simple question. In a certain sense you're "damaging" your
engine every time you turn the key. The higher you rev it, the more it
wants to wear, and the increases to friction, while somewhat predictable,
tend not to be highly linear, not that has to do with the RPM limits of the
valvetrain per se.

You can get valve "float", or the valves bouncing back off the seats, due
to excessive RPM. Depending on your cam and springs, you can also get
spring surge, or harmonic resonances in the springs, which can cause
problems at RPMs well below the maximum. In that instance you might be fine
running all day at, say, 8,500, whereas running for a short while at, say,
7,500 might be death. Anyway, I wouldn't be terribly concearned at 6500.

Measuring your valve train with your valves, your springs, your installed
spring heights, your cams, your buckets and shims, blah, blah, is a sure
way to get reliable data if you can afford and interpret it. The 'Murican
V8's use a gizmo known as a Spintron. Tearing down the top end to look for
fretting is another possibility, though an indirect measure. If your
springs are subject to fatigue failure, one could argue that they weren't
designed properly, but you won't get a refund from the guy who sold 'em to
ya. FWIW, I'm told that the equations for the stresses on valve springs
can't be solved analytically. Don't know if that's really true, or, like
Navier-Stokes, if it's not  terribly relevant....

Anyway, I'm sure others will have more to say.
--
to be removed from alfa, see /bin/digest-subs.cgi
or email "unsubscribe alfa" to majordomo@domain.elided