Off Topic - So I'll Keep It Short - Pistons

[Jorgen Karlsson]

Mike V wrote:

> Hi Walt,
>  When GM designed the Turbo 4.3, they used Hypereutectic pistons
> for strength factors over "standard" cast stuff.  This is mostly opinion,
> but they seem to hold up well, util heavy detonation occurs.
> That is when the the forged pieces appear to be superior.
> Mine have 42k miles on them.  I live very close to a dragstrip,
> so they aren't easy miles.  I use  20+ psi with no problems.
> I have no experience with Hypereutectics and nitrous.
> Detonation would probably be the limiter in that case too..
> hth,


I don't think that the stock pistons in the 4.3 turbo used in the GMC
syclone and Typhoon can be compared to Kieth Black pistons. The 4.3 pistons
are very fragile, the ringlands break all the time. I have been working with
five or six of these engines and not a single piston was intact! We replace
them with TRW L2441 pistons I have heard that most TRW pistons are bad but
we haven't had a single piston failure with these pistons. We use Eagle rods
if anyone are interested, the stock rods are also a very weak spot.


Jorgen Karlsson
Gothenburg, Sweden

----------------------------------------------------------------------------
To unsubscribe from diy_efi, send "unsubscribe diy_efi" (without the quotes)
in the body of a message (not the subject) to majordomo at lists.diy-efi.org