TAN VALVE

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Oct 30, 2013 | 11:52 AM

lumberjack_964

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Joined: Jul 2013

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TAN VALVE

Hello all!

I own a '85 F-150 and I removed the engine(351W) so that I could replace the gaskets on the following: Oil pan, heads, intake manifold and water pump, along with replaceing the water pump itself. Everything went fairly smooth. However, when I popped one of the heads off I found this.

http://picture.vzw.com/mi/812014327_...border=1,0,0,0

can anyone tell me why only the one valve is tan?

Oct 30, 2013 | 12:46 PM

baddad457

Hotshot

Joined: May 2003

Posts: 11,141

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From: south louisiana

Link doesn't work. The short answer is the mixture distribution is diffferent than all the other cylinders. Probably Nothing to worry about. Typical results for any engine, even EFI motors

Oct 30, 2013 | 12:58 PM

lumberjack_964

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Joined: Jul 2013

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Sorry about the pic. Can you only upload pictures from the internet? how can I do it from my desktop? In the picture the rest of the combustion chamber is black from carbon except for the valve. even the other valve is black. that is ok?

Oct 31, 2013 | 11:14 PM

Beanscoot

Cargo Master

Joined: May 2007

Posts: 2,071

Likes: 36

From: British Columbia

Valve color

Typically the intake valves are black, whereas the exhausts are tan to white. This is because the exhaust valves run very hot, and burn off residue. The intakes are cooled by the incoming fuel so don't burn off the bit of combustion residue that condenses on them.

Nov 3, 2013 | 09:46 AM

Conanski

FTE Legend

Joined: Jun 2006

Posts: 31,930

Likes: 1,499

From: Ottawa, Ontario

You only have 1 cylinder that runs correctly and the rest are fuel and/or oil soaked. If the motor runs fine don't worry about it.. it's a carb so there is no getting all cylinders to the exact right mixture, the best you could hope for is the outer cylinders at roughly ideal mix with the inner cylinders rich, and that's because of uneven airflow through the intake.