In a message dated 24/05/02 11:18:01 AM Pacific Daylight Time,
owner-mgs-digest@autox.team.net writes:
> : Again, not sure about this cam. I've been referring to the
> tech articles at www.mgbmga.com quite a bit, as they seem to be the most
> informative, experience-based knowledge base out there on MGB performance
> tuning. Doug doesn't recommend anything more than 225/235 duration for a
> street performance cam, yet the 717 is rated at 280! I'm not sure if the
> reference point for these measurements is the same, so we're comparing
> oranges to oranges. To make matters more complicated, Doug's
> recommendations are for the stock head, which apparently has intake issues
> that prohibit the use of some of the hotter cams for street use. With the
> crossflow head, this may not be an issue.
Apples and oranges. Let's talk old style - the 280 is a good suggestion for a
max for street use, with either head (it isn't really as simple as
generalising from a duration figure - far from it). Any more, and you'd want
a whack of compression to make it sit up and take notice, and that isn't what
you normally want in a street set up these days.
OTOH, you can run slightly higher compression without ping on an alloy head,
so if you wanted to use, say, 10:1, you should have no problem and could use
more cam.
Think carefully about what you are after, though - I have seen far too many
people over-cam an engine. Heck - the special tuning option for the MGA was
to use a Riley 1.5 cam with LESS duration, sacrificing a few horsepower at
redline for a better midrange, which is where you would be most of the time.
Bill
(2 cams, 305 deg!)
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