'63 Exhaust Manifolds Black After Test Drive

[Frederick H.]

Took the car around the neighborhood for it's first test drive after leaving the shop and the exhaust manifolds are turning black on both sides. The shop set the valves to factory specs but the engine was rebuilt back in '89 and I did not get a blueprint to get the cam specs (engine was bored .30), so not sure it's the factory cam. Running combination of 93 unleaded and 92 unleaded without ethanol. I expect the orange paint to burn off but never have seen them this dark - they were natural finish with regular drives on the weekends before the motor was pulled for paint and body and other mechanical work - about 2 years). I haven't had time to check the timing but it starts and runs fine.
Thanks in advance for the help.
Fred
'63 Manifold 2.jpg'63 Manifold.jpg

[Loren L.]

Re: '63 Exhaust Manifolds Black After Test Drive

Looks to me like they're turning cast iron, which is exactly what I would expect.

[Frank D.]

Re: '63 Exhaust Manifolds Black After Test Drive

Exactly what I was thinking.

[Bill M.]

Re: '63 Exhaust Manifolds Black After Test Drive

Years ago after wire wheeling my manifolds back to natural look I read to spray WD 40 on the hot manifolds to keep the natural look. I do it every couple of months it helps keep the natural cast iron looking pretty good.

[Jaime G.]

Re: '63 Exhaust Manifolds Black After Test Drive

Looks to me like they're turning cast iron, which is exactly what I would expect.

they look fine to me. Whats the issue?

[Frederick H.]

Re: '63 Exhaust Manifolds Black After Test Drive

Okay - maybe I just worry too much - they just looked a lot darker than they had before. Thanks for the reassurance - need all I can get.

[Frank D.]

Re: '63 Exhaust Manifolds Black After Test Drive

The same thing happens to painted iron manifolds at the intake heat runners (eventually)...

[Michael G.]

Re: '63 Exhaust Manifolds Black After Test Drive

Remaining carbon from the burnt paint probably makes them a bit darker than the casting was.

[Frederick H.]

Re: '63 Exhaust Manifolds Black After Test Drive

That makes sense Mike - thanks!

[Frederick H.]

Re: '63 Exhaust Manifolds Black After Test Drive

Thanks Frank - guess I need to brush up on my chemistry and a little metallurgy - heat, paint, metal.