Dart heads - off topic (sort of)

[Carl Summers]

Ok, so here I have to disagree.  I will state upfront that someone good with
stones can do an excellent valve job, BUT, it takes 4-5 times longer than
with a Serdi.  A Serdi also has a depth micrometer so you can equalize the
heights of the seats.  Forget three angle valve jobs....the flow is in the
proper radius cut(depending on the head).  The longevity of the valve job
has nothing to do with what machine does it... The width of the 45(or
whatever) has more to do with longevity.  On your asymetric seat thingy... I
would agree if you are VERY talented with stones there are ways to
compensate for flow angles... and its' Berco not Berko
-Carl
p.s. I HAVE done both... 7 years with a Serdi.... I'd take it any day over
almost anything.  If you want your gnats ass of flow increases with spending
20-30 hrs with stones you better have a WET flow bench...and I would still
use sanding rolls instead...after the Serdi.


-----Original Message-----
From: owner-diy_efi at diy-efi.org [mailto:owner-diy_efi at diy-efi.org]On
Behalf Of Larry Heath
Sent: Friday, May 04, 2001 5:07 AM
To: diy_efi at diy-efi.org
Subject: Re: RE: Dart heads - off topic (sort of)


> BTW. if you are having a valve job done, be sure to have the seats "CUT"
> instead of ground. A shop that uses a "Serdi" machine is what you want.
The
> seats have a machined finish instead of a ground finish. youre valve job
> will last longer, and may flow a little better(in theory).
>

This is patent nonsense.

Serdi cut seats and seats cut using stones are no different, EXCEPT you can
do the seats in a head a hell of a lot faster using a Serdi machine, i.e its
more cost effective for the shop. On top of that they charge more because
they have the newest hot lick machine and it takes less time to do. They
make more money. It also depends on who is doing the work, either way. I
have seen butcher jobs using a Serdi machine as well as using stones or
Neway cutters or any of a half dozen different methods of putting a seat in
a head, it still depends on who is doing the work and how well trained they
are and how much care they take in doing the job.

You cut a seat using a Serdi machine and a seat using stones and if there
the same angles and widths you are going to get the same flow and the same
life. I use a Serdi ( its actually a Berko) and I use stones, mostly general
rebuild stuff on the Berko and race stuff using stones. There are things you
can't do using a Serdi machine such as asymmetric seats.


Don't buy into the advertising and propaganda that you have to have a Serdi
machine to do superior work, cause that is plain crap!

Later Larry




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