Carl Fausett

I just saved a set of GTS heads for a customer. He couldn't find good used GTS heads anywhere at anything like a reasonable price. Restoration was the way to go.

Here are the before pictures.

Carl Fausett

Pics after media blasting had removed the corrosion.

Carl Fausett

Pics after the weld-up. You can see some contaminates still resided in the metal, and they were brought up and out by the welding. We milled the heads to expose the porosity and re-welded. These heads required three rounds of welding/milling and welding again before we got a surface that would hold gaskets.

Carl Fausett

..and final finished pics. A valve job was also done on the heads before they were returned to the very happy GTS customer.

V2Rocket

fantastic work...truly invaluable service offered here.

Strosek Ultra

We all know welding may make a cylinder head to distort. For the 2V heads it is a minor problem as the 2V-heads can be surface grinded all flat on both sides. If a 4V head is distorted we will face a difficult problem with the cam bearings not lining up properly. However the 4V head is a large chunk of aluminium that resist warping. It is recommended to preheat the cylinder head before welding.
Åke

Carl Fausett

This pair of 16v heads was exceptionally dirty, and even after removing the corrosion, cleaning, and TIG welding, we still had small pockets caused by gassing of an impurity.

Laser welding allows us to get down into those pockets (some were .100" deep) and fill them from the bottom up. Each weld puts down a layer .007" deep, then it is let cool, and then another layer is put down on top of that, and so on.

It's really something to watch - the welder is operating robotic equipment by hand and welding thru a 10X power microscope.

It's also expensive as all get out... so not a regular part of our head restoration process. It's just nice to know we have it if we need it, like in this case.

NickTucker

damned impressive!

928 GT R

This one deserves a bump.

Great work Carl!

How do you get the heads/passages so clean?


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Carl Fausett

When we are restoring corroded heads, of course, all the corrosion has to be cut out before we can begin welding.

We use a combination of media blasting, then die grinders and sometimes even plunge milling to remove the corrosion until we can get to clean solid metal. Then the first weld-up happens, and a following surface milling to see what we got. Usually, a few impurities will pock-mark the weld, and we have to cut those out and go back through a second welding pass.

Really bad heads, like these were, can take more. These heads took 4 passes through welding and surface milling until we were pleased with them.

FredR

Carl,

When welding how do you deal with undercut?

Presumably you mill the entire face until the undercut is resolved and in the process lose a small amount of head material to the undercut which presumably is going to be less than 1mm.

I have a spare set of GTS heads that came from the original motor when my GTS was new. The PO had a problem and took the heads to a machine shop who tried to mill out the corrosion- a big mistake in that like you, they should have welded up the corroded material first. Not sure how much they removed but if a repair were to be effected the head has lost one layer and after welding would need another layer removing. I dare say a thicker gasket would resolve the problem.

Carl Fausett

I'm not quite sure what you are referring to as "undercut." Please explain.