White build up on valves?

[bluegs03]

Hey guys i recently purchased a used but recently >20000 miles refurbusished cylinder head. Ive checked the valves for being bent and they are in good condition. I knew when i bought the head that it had some white crusty stuff on the exhaust side. So i bought it and started to clean it up. the white stuff literally looks like a barnacle crusted on all of the exhaust valves. Everyone is covered in this stuff. None of the intake valves are covered though.

So my question is what could of caused this meth injection? Nitrous Oxide? Is it harmful to the integrity of the valves?
Here is as good of a shot as i could get of the white stuff. I tried to do a google search but i couldnt come up with anything due to my ineptitude at wording it correctly.

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I scraped most of the white stuff off and the valves look ok under all of this stuff.

 

[98mitsuGSX-SD]

A build up a white residue is usually due to a motor being ran too lean but as you can see in the pics only the exhaust valves are white where as the intakes are black with carbon. I'm sure the valves haven't suffered from anything that would hurt them. I would take the head to a machine shop and have them clean it up for you and machine it flat so you won't have any issues with it not properly mating to your block.

 

[Defiant]

It's from the modern crap they sell to us as "gasoline".

 

[linksys42]

So are you saying this is from an aftermarket additive like fuel system cleaner or are you saying this is and additive the gasoline companies mix in the gas from the refinery?

 

[BoostFrenzy]

I think he's saying that the standards of gas quality makes engine parts look like this. Where did he say additives?

 

[architechnik]

Oh, did you say you wanted 94 octane? Sorry, all we have is 87 octane that we slap a 92 on so we can charge you thirty cents extra per gallon.

Here's a hint: Don't buy "grocery store" gas. If they specialize as a low price leader *cough* Wal-mart *cough*, they likely specialize in low quality product *cough* definitely wal-mart *end-cough*.

As for the color difference, white means hot, black/sooty means cold. Can you tell me why the intake would be colder than the exhaust end? With such a temperature difference, I may think that the engine was running a bit hot, although with the intake so cold, I would guess there was a lot of air cooling that side. Perhaps the engine was running a bit lean.

 

[bwild97]

White ash is normal on the exhaust valves, it's a result of the never ending serch for a cleaner burning fuel. Every fuel company has their very own clean burn package that gets added to the fuel while the tanker gets filled at the depo.

 

[motomattxxx]

It is caused by fuel additives, and is more likely to be found on an engine that ran high test due to the added octane boosters in the fuel. The white deposits should be removed from the valves by removing the valves from the head and then cleaning and reseating them since the white deposits will act as an insulator and cause the valves to hold in more heat than designed for.

 

[bluegs03]

thank you guys! im glad that its not to serious . This stuff is HARD to get off i have been working on this for almost 2 weeks, i got all of the old soot off of the exhaust valves, but this white stuff is nasty. I think i might be a machine shop to get the remaining stuff off of the valves because i dont think that i can get it off.

I am also going to have the head checked for warpage (really easy i can do it myself) and possibly resurface it. Thoughts? because it was so lean i think there might be warpage?

 

[Defiant]

You'll probably be ahead to have a shop media blast (walnut shell or glass bead) those valves, at which point you may find aftermarket replacements cheaper.

Aluminum heads almost always come off crooked, making shops thousands and thousands of dollars in flycutting. See what the shop thinks.

 

[DKneble]

Doing a complete overhaul on the engine compartment right now since the trans is out to shep for a couple weeks and noticed something when I yanked the exhaust manifold off. In the head and on the valves there appears to be some white and yellow residue, like a chalky powder that seems to wipe off and would definitely come off with a brush. I was running C16 for a couple days just before I yanked the trans...is this the lead in the gas? just curious...and should I bother to try to clean it or just let it burn off? Thanks

Dave

hate to double post here but i think my case is a little different from the previously mentioned one in this thread and just wondered if anyone had some ideas?

The yellow residue that i can see is on the top of the valves and around the exhaust tract in the head. Its very fine and powdery and less then 5k miles ago there was none there at all (last time I had the manifold off). Motor was definitely not running lean before I started yanking it apart, maybe very rich tho. I realize white usually means hot and black means cold. I have just never seen this before and obviously its very recent.

Dave

o, and btw the valves are SI SS 1mm oversized valves

 

[Defiant]

It's all the same crap, and for the same reason: modern fuels are shit.