Another happy Keith Black hypereutectic piston Customer here. I run 'em in
my 400 HP '68 Camaro. Speed shift at 6500, goes to over 7000 before it
grabs. Great step up from cast piston without the cost of a real race
piston.
What James was saying is that you install cast and hypereutectic pistons
with a tighter piston-to cylinder wall clearance than a forged piston.
Sometimes you can hear piston slap on a cold engine with forged pistons and
their loose clearances.
Personally, I would use the KB hypereutectic pistons in my 3.9 Rover if I
could get them. And I'm sure I'll run it harder than you will. :)
Carl F.
MGBV8 in TN
----- Original Message -----
From: "James J." <m1garand@speakeasy.net>
To: <CraigFaubel@aol.com>; <mgb-v8@autox.team.net>
Sent: Thursday, February 26, 2004 8:00 PM
Subject: Re: piston choice
> Craig,
> I have found that Hypereutectic pistons are quite cheap, if it is
> not a custom order. They give you that extra bit of strength, and they
> don't expand, contract, and rock like forged ones do while they heat
> up. Think of how long many cars go with their original cast OEM
> pistons. 10 years or more. Usualy the piston is not what fails. Most
> cars are sold long before the internal components suffer irreperable
> damage. Usualy it is a bearing problem, and often that is to a gummed
> up oil system, not just material failure. Also, we are putting these
> engines in cars that are only 60% of the weight of the OEM cars. Take
> the T-5 transmission, for example. It is rated for an engine producing
> no more than ~300 Ft-lbs (depending on the year). But that rating is
> based on a 3600lb car. They actualy can handle much more torque in a
> 2100 lb car.
> So stock pistons are actualy a safe bet in our little cars, and
> hypereutectic ones are great insurance, and can handle mild boost or
> nitrous (key word: mild) Forged are the strongest, cost twice as much,
> and will cost you torque on short drives because of all the blow-by
> before the piston fully expands (although some new alloys have a much
> lower Coefficient of Thermal Expansion).
> I'm using the Ford 255 pistons (+0.030) in my Rover 3.9 stroked
> engine, as per the LaGrou recipe. I only bought cast ones because no
> one makes a stock hypereutectic replacment that isn't a custom order
> (key word: expensive). But all the ones I've seen for Ford 302/351 and
> SBC Chevy are very reasonably priced.
> Best of Luck.
> JJJ
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