The Original 355 took a hit....

[Kevin R]

Where you still running the x-fire or what?

Kevin R


>
>
>
> The 355 that I wrote about in tuning tips, and used for lots of 747 info.,
> finally had it's first internal problem.   Well over 100 1/4m passes, and
> too many 600' passes to even guess at.   Now at about 70K miles, it's
blown
> a headgasket.  Happened on a really cold night, and the stations are known
> for adding lots of alky during the cold season, so I'd be easily talked
into
> it being not a real tuning problem, per se.   It microscopicly (?) blew
the
> fire band over maybe .020" near a water passage hole (rear side of #7).
My
> best guess is that there was a tank or two of heavily alkied fuel, and was
> just enough trace detonation that it silently lifted the head.   We've had
> enough single digit temps., that I just should have taken an addition 2
> degrees of timing due to the weather <sigh>.....
>   Just to summarize, this was a Comp Cammed, 9.5:1 AL vett headed SBC.
>   At this stage the hone pattern is fully intact,  the pistons still have
> there crisp corners at the perimeters, no incidation of any valve burning,
> no large amounts of Carbon,  in general the wear is typical of a 10K old
> stock engine.
>
> While apart, for the gasket change, going to clean the chambers (smooth
> them, to avoid any machining edges), do a little pocket porting, and
freshen
> the valve job..
> As much as a success this engine has been, just can't help to entertain
the
> idea of surfacing the heads, and tweaking it up a little more in HP.
> While not a screamer HP wise, it's spent alot more time at WOT then most
any
> other street motor that I can imagine.
>
> Course, there are some ecm options, for things to do <g>.
>
> Course being the President of CSH, I'm also a customer.
> Bruce
>


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