Porsche 907 engine color question

[magicmustang]

Okay, I got a question for you Porsche experts out there. What color was used on the block, injector tubes, cooling fan and housing of the 1966 Porsche 907 flat 8 Boxer engine? See enclosed pic.  Thanks in advance for your replies.

Edited September 18, 2018 by magicmustang

[70mach1]

It looks to be a light zinc chromate,  Generally used over raw aluminium.

[Vince Nemanic]

Most of the parts you are asking about are unpainted fiberglass. While I haven't seen a 907 engine, I have seen 910, 904/6 and 908 engines at the Monterey Historic Races. The fiberglass that Porsche used on the injectors, fan shroud, and fan are a translucent tan-kind of like coffee with a lot of cream in it.

[Ace-Garageguy]

What you're seeing there as the "block" is in reality the engine cooling "tin", made from sheet aluminum, or fiberglass. The cooling "tin" on your particular example appears to be the fiberglass version, which is the natural translucent gray-yellow color of the material. As 70mach1 notes, it may have a coating of yellow-green-gray zinc-chromate, and is

also similar to the color of the old Dow 7 coating. This is a magnesium Porsche engine case done with Dow 7.    There's a thread on here somewhere

about matching the color. And this:  https://www.jalopyjournal.com/forum/threads/what-color-paint-to-use-to-match-dow-7-coating.235753/

When these engines get restored, repairs to the fiberglass cooling shrouds are often needed, and short of making new parts, there's no way of doing an invisible repair worthy of a megabuck historic car...so the shrouds are sometimes painted with a color that approximates the original fiberglass.

The fan itself can be either cast aluminum or molded reinforced plastic, which is a translucent yellowish whitish, kinda like the shrouds, but slightly different. 

The injector tubes could also be molded glass-reinforced plastic, same color as the engine cooling fan (though a slightly different hue in your photo), or fabricated aluminum

The fan duct was fiberglass, and is also the natural translucent yellow/gray color of f'glass moldings.

Porsche had a thing for plastic fuel lines in those days, and they were a milky white, also slightly translucent.

Here's another engine. In this case, the intake trumpets are the same color as the fan, indicating they were made by the same process at the time, in closed, matched molds. The airbox lowers and fan shroud are a slightly different color here, and look to be open-mold, hand layups (due to the slight irregularity of the color, and the relatively simple shapes).

EDIT: The earliest versions of these engines used sheet aluminum engine cooling "tin". When you look closely at the fiberglass version of the same parts, it's very obvious that the molds were made from sheetmetal masters. I do not honestly know if any were raced with the aluminum cooling jacket, but most definitely, prototype, test, and development engines would have been so equipped.

Edited September 19, 2018 by Ace-Garageguy

[magicmustang]

Hey guys, thanks for your replies. I will now try to paint them appropriately, if I can come up with the proper colors.

[magicmustang]

17 hours ago, Ace-Garageguy said:

What you're seeing there as the "block" is in reality the engine cooling "tin", made from sheet aluminum, or fiberglass. The cooling "tin" on your particular example appears to be the fiberglass version, which is the natural translucent gray-yellow color of the material. As 70mach1 notes, it may have a coating of yellow-green-gray zinc-chromate, and is

also similar to the color of the old Dow 7 coating. This is a magnesium Porsche engine case done with Dow 7.    There's a thread on here somewhere

about matching the color. And this:  https://www.jalopyjournal.com/forum/threads/what-color-paint-to-use-to-match-dow-7-coating.235753/

When these engines get restored, repairs to the fiberglass cooling shrouds are often needed, and short of making new parts, there's no way of doing an invisible repair worthy of a megabuck historic car...so the shrouds are sometimes painted with a color that approximates the original fiberglass.

The fan itself can be either cast aluminum or molded reinforced plastic, which is a translucent yellowish whitish, kinda like the shrouds, but slightly different. 

The injector tubes could also be molded glass-reinforced plastic, same color as the engine cooling fan (though a slightly different hue in your photo), or fabricated aluminum

The fan duct was fiberglass, and is also the natural translucent yellow/gray color of f'glass moldings.

Porsche had a thing for plastic fuel lines in those days, and they were a milky white, also slightly translucent.

Here's another engine. In this case, the intake trumpets are the same color as the fan, indicating they were made by the same process at the time, in closed, matched molds. The airbox lowers and fan shroud are a slightly different color here, and look to be open-mold, hand layups (due to the slight irregularity of the color, and the relatively simple shapes).

EDIT: The earliest versions of these engines used sheet aluminum engine cooling "tin". When you look closely at the fiberglass version of the same parts, it's very obvious that the molds were made from sheetmetal masters. I do not honestly know if any were raced with the aluminum cooling jacket, but most definitely, prototype, test, and development engines would have been so equipped.

Hey Ace, here's what I did so far. Colors are not exact (zinc chromate and light tan) but closer. Had to scratch build a fuel injector pump. 

 

Edited September 19, 2018 by magicmustang