spridgets
[Top] [All Lists]

Re: cam timing- question 2002 08:37:50 -0800

To: grbyrns@ucdavis.edu (Glen Byrns)
Subject: Re: cam timing- question 2002 08:37:50 -0800
Date: Thu, 17 Jan 2002 07:38:30 -0500 (EST)
Cc: spridgets@autox.team.net
There you go, Glen!

Advance is "quick" retard is "fast"; torque
or horsepower. A question of "extent" rather than "black & white", of
course. 

Dave Vizard does more than a page on
this stuff and explains all he knows as a
pro about this, in layman's terms.

When I e-mailed Dave with my engine
specs. with Rivergate motor "tailored"
for Judson, he asked me the gearing of
the unit and in what rpm range I'd be
operating in most of the time, as I use
my Frog as a daily driver in normal
suburban driving and traffic. He made
a cam recommendation along with dialing
in recommendation inclusive of his reasoning.

Not surprisingly, he backed up my choice
of a 1275 Cooper "S" type through 1.5
rockers, advanced 4 degrees or so for the
application for a couple of reasons:

1. Most factory cams came through retarded slightly, anyway, "back
then". 
(not ISKY, Crane, APT, Elgin or aftermarket performance types which
should be "spot on")

2. Moving the cam forward would bring
this grind very close to the modern TurboMetro grind, which works
exceptionally well (this cam was actually
my first choice but not available at the time the engine was built).

3. As daily drivers, how many of us tool
around more than 75-99% of the time at 5,000rpm, plus?

It's the "other way", isn't it? And "torque"
is generally the name of the game in
a "street" application. So, bringing up
the bottom end by "advancing" the grind
a bit at the expense of the top end (which
you hardly ever use, anyway) pays dividends in the type of driving you
really
do on a daily basis, in terms of torque and
thus, economy. No need to go to very high revs to "go" now! Easier on
the mechanicals - now, that's real economy!

There is more but, in a nutshell, there you
have it.




Cap'n. Bob
    '61 :{)

///  unsubscribe/change address requests to majordomo@autox.team.net  or try
///  http://www.team.net/mailman/listinfo
///  Archives at http://www.team.net/archive/spridgets


<Prev in Thread] Current Thread [Next in Thread>
  • Re: cam timing- question 2002 08:37:50 -0800, Unknown <=