93 with the 4.0, doing my exhaust manifold and decided to check out the exhaust valves and all of them except 1 are very white. #1 exhaust valve is white with some orange on it. Is that reason enough to take the head off?

 

 

Interesting. Any negative symptoms while running?

If you do pull the head make sure to post pictures of the combustion chamber side of the valve so we can see!

 

it runs good, idles good, on a hot day like 90+ if i run the AC while sitting in traffic or idleing it will start to run hot but it doesnt burn coolant, barely burns oil, no mixing between the two. no smoke in exhaust

 

Hmmm... Google is saying orangish deposit on exhaust valves are harmless and to be expected. Could be from that injector giving that cylinder slightly different fuel amount. Fuel additives can do it, and I see where oil seeping past the valve stem seal has produced similar results.

How do your spark plugs compare to one another?

 

For heck of it, while you have your plugs out, stick that endoscope in the cylinder and see what it shows! If you have a side facing camera function use that too. DO NOT clip on the little mirrors that come with some, if the clip on falls... that's a sure fire way to have to pull the head

 

I recently replaced spark plugs a couple months ago this is what they looked like.

 

ive used various fuel injector products and lucas oil stabilizer over the last year

 

I'm the curious (waste a lot of time and energy) type.. I'd be compression testing, leak down testing, flow rate testing injectors, checking for temp difference on exhaust runners and lord only knows what else until I found some difference for that cylinder. And in the end it would be for nothing but satisfying my craziness. That motor will probably run fine for a long while if you just put it back together.

Hopefully the smart folks here will have a better answer for you.

 

Professional machinist guy here. Done 100's of heads. Normal coloration, you're good on that.

 

What do the intakes look like?

Back in 2007 I replaced the cracked exh manifold on my '88. Discovered when I ran some Seafoam through it. Had around 175K at the time. Exhausts look the same as yours. My intakes were very clean.

 

Took the head off because I suspected a bad head gasket, looks like I couldn’t have been more wrong. Good learning experience tho. My buddy is saying the stamp on the piston means it’s been rebuilt?

 

At first, I though .050 over. However, a few web searches later, several old posts from other forums suggest the FRT 50 indicates a stock bore. You should measure to be sure. Bore size is 3.8759 to 3.8775 in.

 

By the look of the leftover gasket stuff on the Block I would say that that was the OEM Factory assembled gasket. That may be the very first time that engine has ever been cracked open.

 

The gasket had a brand name on it “apex”