Hi,
just got my head off my Volvo 740 from 92. One valve has a different color. Any ideas why?

Thanks!

That is oil from the valve seal on that valve. The intake valve will show up fast because you have a vacuum in the ports when idling and cruising.

White exhaust valves is a tad too lean, but that is what you need to keep the cat con alive.

I tried to get the image in there... But I hear you. One of the intake valves is black. All others are white. Just curious what if someone knows what that could mean.

GALLERY/images/13212.jpg

If you go to the image gallery I think you will find the image that I uploaded.

The picture of the head is currently the last uploaded picture here:

https://www.brickboard.com/IMAGELIB/?js_link=1&pix_type=TECHNICAL

incomplete combustion. leaking injector, poor spark and/or low compression. good luck, chuck.

I saw this post early in the morning and the photo was embedded--now it isn't. My first thought on finding white covered valves would be oil burning--with something else going on (like a leaky injector) in the cylinder with the black intake. -- Dave

Thanks for your responses. I'll get hold of a new injector and see if that helps. With that and a renovated head - that's pretty much all I can do for this car. A deeper teardown of the engine is beyond my skills.

200k miles.

It doesn't consume an abnormal amount of oil. Maybe a quart per 3000 miles.

Will keep you posted on the results.

looks something like a burnt valve - which is usually an indication of excess air in the combustion chamber.

What prompted you to remove the head?

what color? 3 black 1 white? 3 white 1 black? we can't see under your hood, the light here sucks, chuck.