more heads on the way--valve timing

[ssspoon@aol.com]

On Mon, 8 Jul 2002 10:177 EDT
We received this very interesting tidbit from Adam of Z1 Performance at
Z1Auto@aol.com

Subject: Re: more heads on the way-2.5 heads for sale-valve timing ...

"After you do head work (porting, increasing valve seat area, etc.) you begin

to find very little differences between the heads. We have had every Subaru
head we know of to date (from the Legacy 2.2 turbo onwards, 2.5 DOHC, SOHC,
and Sti V4 and V5 heads) on the bench and after being worked, there very
maybe 1%-2% differences in flow"

The reason this is very interesting to me, is because a few months ago we had
bigtime discussions about the relative differences in headflow amongst the
various heads. The general consensus seemed to be was if you started with
heads exhibiting superior flow and tricked them out, you would still enjoy
whatever flow advantage there was over trick heads with less initial flow.

There were a couple of notable exceptions to the general consensus, and from
what you say above Adam, gives me cause to appreciate the knowledge of those
exceptions with excitement. If that means the proper effort put into my old
style EJ22T heads will give them nearly the same flow as working over the new
22nd Century heads, that'd be slicker than robot snot, and I'll be happier
than a pig in shit.


You also said "As for valves, bigger is definately not better - the head is a
unit and needs
to be built as such...if you don't have the right valvetrain in there, or
cannot get the proper seat area, or cannot get the proper grind out of the
cams, then bigger won't do a thing for you"


And this is what my investigation right now is about. About looking at
alternate valvetrain options to make a different cam profile worthwhile. I
am friends with Dan Paramore whom I consider to be a very knowledgeable
engine builder. He has ported two sets of heads for me. I would like to be
able to provide information and components for this next set to enhance my
overall performance, and especially low and midrange torque.

If I can find and afford lighter and maybe larger valves, lighter and maybe
roller rockers, all with the intention of complement the porting, polishing,
and other tricks, the right cam could be the icing. Do you have any
suggestions or sources you can share?

Larry Witherspoon
Torrance (Los Angeles)
ssspoon@aol.com

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