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Background: This motor has sat for over a year now. I pulled off the header to replace the gasket and weld up a hole, and noticed some gold sparkly debris in the header and in the port. If I touch said sparklies, they turn into dust.

I decided to borescope the cylinders and see what I could see, and to my surprise, I found some weird deposits on the crown of the piston.

The motor runs fine, and is not suspected of having any experience with detonation.





Has anyone seen this before? Or do you have any guess what this could be?
 

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My guess would be bad brass valve guides. Depending on who built the heads.
 

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My guess would be bad brass valve guides. Depending on who built the heads.
Jim O'Neill, Renegade Racing. That motor has roughly 20k hard miles. I don't doubt his abilities at all, so it shouldn't be the guides.
 

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Send the deposits to Grog and he should be able to run them through a mass spectrometer and tell you exactly what it is, although his boss might not like such use of said spectrometer lol.

But really, first thing would be to check if it's magnetic. If it is, it can only come from the header or valves, unless they are a non-magnetic stainless steel.
 

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Send the deposits to Grog and he should be able to run them through a mass spectrometer and tell you exactly what it is, although his boss might not like such use of said spectrometer lol.

But really, first thing would be to check if it's magnetic. If it is, it can only come from the header or valves, unless they are a non-magnetic stainless steel.
They would kill me. :)

That looks like brass; something may have been ingested, and is now everywhere.

If it's in the exhaust or intake, it's everywhere; especially if it's so fine "If I touch said sparklies, they turn into dust." :)

Both tracts see a partial vacuum at some point, and stuff will go everywhere.

If the car sat, it could be metal that dissolved from acid in the oil or electrolysis, then pooled and reconstituted elsewhere. Bronze in suspension would be copper and tin mostly, and would loosely plate out on aluminum.

Whatever dissolves bronze would rather dissolve aluminum, lol. Thus the copper/tin is left, like gold foil.​

The last time I saw something like this was in the 70's, in a 2-stroke dirt bike. The bronze wrist pin bushing was evaporating... from heat and water, lol.

If you want a sample, put vaseline on a long cotton swab, and touch whatever it is, it will stick.

If you know anyone with a microscope, you can prep a slide pretty easy: Flush it off the swab onto a slide with rubbing alcohol; you will probably see silver and copper areas, indicating bronze. Dilute Sulfuric Acid will make it turn blueish in a couple of minutes.

If it dissolves in alcohol, it's not metal. :)


A lost gold chain in the intake can do the same thing, although you really don't have to worry about a gold chain; it's too soft to damage much, unless it hits a valve. :)

All that said, if there are no chunks, and the stuff is that fine, you should be ok; this is a drag engine.

There's going to be some erosion; this is what valve guide wear looks like, I'd bet.

Have you ever run Nitrous? That could easily be valve guide material, and it really doesn't matter who built the heads, lol.

Hell, the aluminum exhaust port is probably fire-polished at 20k miles; nice and smooth. :D

EDIT: The reason I say Brass, then talk about bronze valveguides is the composition of bronze; zinc won't come out like the copper and tin, what will is brass. :) (copper and tin, where Bronze is copper tin and brass. Mostly, lol.)
 

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...

EDIT: The reason I say Brass, then talk about bronze valveguides is the composition of bronze; zinc won't come out like the copper and tin, what will is brass. :) (copper and tin, where Bronze is copper tin and brass. Mostly, lol.)
:tongue: :rolleyes: Thanks for vindicating what I said earlier. Us metals guys know what we're talking about. ;)


What I meant about "depending on who built the heads" was - more precisely - depending on the type of valve guide that whoever built the heads used...

Cast iron or bronze.
 

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:tongue: :rolleyes: Thanks for vindicating what I said earlier. Us metals guys know what we're talking about. ;)


What I meant about "depending on who built the heads" was - more precisely - depending on the type of valve guide that whoever built the heads used...

Cast iron or bronze.
Im not a metal guy, just a dumb mechanic.

There are many kinds of valve guides used on different cars ..

Copper alloy, Aluminum, Cast iron, Powdered metal, Silicon bronze, Phosphorous bronze, Manganese bronze, Aluminum bronze, etc ..

But yeah, you're right, gold shiney dust is not likely to be actual gold and probably came from the guides. ;)
 

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It could be a gold mine.

Stake a claim.

He he, theres gold in dem dare holes.
 
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