Update by Per Schroeder to the
Alfa Romeo 2000 GTV project car
Jun 20, 2007
We didn’t remove the valve guides for this work and it was a bit of a problem and a compromise. It would have been better to remove them so we could clean out the area better. As it stands, we got most of the benefit of porting, without the expense of replacing all eight guides.
Our tech editor, Per, has never ported a head in his garage before, so we let him have a go at the Alfa’s twin-cam noggin. He used Jim Kartalamakis’s guidelines that are published in his book, “Alfa DOHC Engine High Performance Manual” printed by Veloce Publishing. You can find Jim’s book through Motorbooks.
We started out by removing material with a die grinder and a steel bit. Once the bores and ports were shaped how we wanted, then we used a stone bit and a Dremel to smooth things out.
We didn’t remove the valve guides for this work and it was a bit of a problem and a compromise. It would have been better to remove them so we could clean out the area better. As it stands, we got most of the benefit of porting, without the expense of replacing all eight guides.
A sanding wheel gave the head the final polish before its trip back to the machine shop for decking.
As for the exhaust manifold, we’re inclined to think that a decent 4-2-1 cast iron piece is sometimes better than a cheap header, so we’re going to clean up the ports on our Alfa’s manifold to smooth the transition from the head to the exhaust system. As you can see, the ports in the head aren’t quite lined up with the manifold. Um yeah, that’s bad.
The first 1/2 inch of the manifold will transition to the port smoothly enough when we are done.
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