In a message dated 11/27/00 6:47:35 AM Pacific Standard Time,
owner-mgs-digest@autox.team.net writes:
> I will be doing a major rebuild on my 1980 MGB LE motor this winter and
> want to squeeze a bit more power from her. The car is dead stock at
> present. There are numerous suppliers touting cam kits. I want to be
> able to do a normal installation, retain the valve timing and adjustment
> settings as close to stock as possible, just so in my advanced years I
> will remember them. What is the list's experience with after market cam
> kits relative to modest power gain without sacrificing bottom end
>
If you are changing the cam and nothing else, your result will be minimal or
even negative.
Back in the good old days, MG even suggested the fitment of a Riley 1.5 cam
to slightly detune the engine for better midrange action (which is where the
engine gets the most use on the street).
Just putting in a bit more cam will likely lose you some gas mileage, but
without addressing the power bottleneck, which is gas flow in the head, you
won't likely notice any change in performance. This mod ranks right up there
with adding a Weber to a stock engine in terms of results per dollar (in that
case, about $300 per horsepower).
You are presumably looking for something to do to give you a noticeable kick
in the pants when you boot it. To give you some idea, I once took a dead
stock MGA motor, blueprinted and balanced for a stock class, but with a very
decent Janspeed prepared head on it, and added the equivalent of the old AEH
714 (going by memory here guys, so it could be the wrong number) 'rally' cam.
I could not tell _any_ seat of the pants difference, but it did indeed reduce
lap times by a second and allow me to stay with other cars that had been
slightly faster before.
So if you want to do anything that gives you a readily detectable qualitative
difference, I'd toss the servo, so you can put on earlier twin SUs, go with
the mild cam, but spend a few bucks on the poor head first, and if the budget
allows, use higher compression pistons, say at least 9.5:1. But just a cam
change? I wouldn't waste the money.
Bill S.
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