A great find at a local boneyard! And some questions ofcourse...

[marc_scirocco at sympatico.ca (Marc_Scirocco_Québec)]

It is always a pleasure to read a post from our most literate member ;-)

I am almost done in building a 9A bottom/3A Audi head combo, and I had the
same questions as you do regarding the Audi 3A head.

So here are my observations regarding both JH/3A heads, and why I am going
to use the 3A head.

Actually, both heads are very similar. They both have the same ports, the
valves are the same size.

The JH is a mechanical head, while the 3A is a hydraulic head. +1 for the 3A
head. This is for a street motor, that will not rev above 6500, so the low
maintenance factor of the hydraulic head is a plus. Not that big of a plus,
but a definite plus.

You can use your CIS mechanical setup with this head. It is a direct fit.

Now lets talk about the intake manifold. This is where the main difference
comes to play.

I read the same thing as you did regarding the injectors. Being mounted on
the intake manifold instead of the head would allow them to run cooler. +1?
No data to prove this, so I'd say no, but it will not hurt.

One plus for the 3A intake manifold, is the ease to get the injectors out to
replace the seals as regular maintenance compared to the JH head. For those
in the dark, they are held by a plastic clamp (they are cheap at the
dealership) held by two 10mm bolts. You wrench two bolts on the 3A head to
get the injectors out instead of cursing and prying the JH head injectors
out. +1 for the 3A

I measured both the JH and the 3A intake manifolds runners. The 3A intake
manifold runners are bigger. Not that much, but bigger. The throttle body
opening is already big enough as is for a neuspeed TB without the adaptor
plate. +1 for the 3A.

The 3A intake manifold is not a direct fit. You have to plug the 5th
injector hole, which is in the middle of the back of the intake manifold,
and make three holes on the end of the manifold for the correct location of
the 5th injector. +1 for the JH.

The head/intake manifold odd shape gasket is available for a few dollars
more than the JH gasket at the dealership.

I got my 3A head for cheap on ebay, like 100$, and it was from a low miles
motor, as the injectors look almost new, and there was not much dirt on the
head.

I also did port and polish the 3A head, got it rebuilt, and matched the
ports, polished the chamber, and unshrouded the valves.

My main reasoning behind all this, is: Audi built this to power a bigger and
heavier car, so there has got to be a small torque advantage with this head.
This is my opinion. Now I will need to get some numbers once this swap is
done.

It will go on top of a 2008cc bottom end (83mm pistons).

My main goal is TORQUE. Lots of it. This with a close ratio transmission on
a lightweight car. It should be fun to drive around town.

Cheers.

Marc
'83 Scirocco
'97 A4

> -----Message d'origine-----
> De : scirocco-l-bounces@scirocco.org
> [mailto:scirocco-l-bounces@scirocco.org]De la part de stetson
> Envoy? : dimanche 14 mars 2004 01:57
> ? : scirocco list
> Objet : A great find at a local boneyard! And some questions of
> course...
>
>
> Today was an excellent day.
>
>
> Which head should I use? The JH or the 3A? I know that I can throw on the
> JH as it's a known good mod, but are there any advantages to trying to
> keep the 3A head and use it? Bigger valves, etc.?
> I'll be getting the manifolds w/ the injectors. Could I use that w/ my CIS
> fuel management?
> The injectors are mounted in the manifold runners which I saw on a site
> somewhere could attribute to "cooler running" IIRC?
> Any thoughts on that?
> Other than that it looks A LOT like the Fox intake/Audi 5k TB I presently
> have and love!
>
> The throttle body looks to be the larger Audi 5k type but with cable
> mechanism like a 16v versus the mechanical linkage of the 5K or stock TB.
> You folks think I can just get a 16v cable and use it with the TB?
> Maybe concoct some sort of frankensteinian post set up for the WOT and
> idle switches to be activated by?
> The exhaust manifold I know I can't use and so I will be impressing the
> 4-2 reamed out rabbit one that I currently have on (and the winning head
> arraingment will be being accompanied by both manifolds to the machine
> shop for port matching!) into service.
>
>
> Thank you for your indulgence and any opinions you may wish to offer!
>
> Tim
>
> If I had to live my life again, I'd make the same mistakes, only sooner.
> 		-- Tallulah Bankhead
>
> "If a nation values anything more than freedom, it will lose its
> freedom; and
>  the irony of it is that if it is comfort or money it values more, it will
>  lose that, too."
> -- W. Somerset Maugham
>
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