Hi guys. I was working on a fellow member's S2K today and I was really surprised when I pulled the valve cover off. I had never seen a valve train like this, bright orange!



Additionally I had found black gunky deposits around that I had never seen.





Look near the deck.



Is this normal? FWIW, the coolant looked like blue type 2, not the pink long life stuff.

Background: The car came in and had codes for misfires on all cylinders. I checked the spark plug tubes and found oil. After pull the valve cover I found that the spark plug tube seals were all installed upside down
Compression was excellent at 240-250 across the board.

 

Do you know what oil it's been using?

 

Never seen this. But I've only seen the cover off two (2) S2000s. Keep us up to date.

Upside down spark plug seals is an indicator the cover's been off before.

-- Chuck

 

I reckon it could just be shit oil that has gotten too hot.

 

I can't say that I know "anything" about the Honda engine, but if that looks like rust, I guess blown head gasket.

 

Too long oci is my guess

 

That is conventional oil staining and buildup.

If you use synthetic, you will never accumulate the slightest trace of anything.

 

Yep, I discovered this same coloration and asked Billman a couple years ago about it when I discovered it while doing a valve adjustment on my AP2 after I had bought it, and he obviously said the same thing. I can tell you that I only use high quality full synthetics in all of my vehicles, but the previous owner must have used conventional. What I can also tell you, is that stain will not go away (at least anytime soon, but I'm pretty sure it's permanent). It's not going to affect anything, just start using a full synthetic. I did 3 OCI's with full synthetic and the stain was still there. I even added 1 bottle of AutoRX to 2 of those OCIs, and it didn't change anything. Motor run happy though, so even though I'm anal about stuff like this... the car is 100% fine. It's literally just a stain, nothing is compromised from the stain itself being there.

 

I agree. That orange/brown stain is called "varnish". I found that same (although a bit more brown than orange, without the pieces of gunk) varnish in my MDX after a number of years using dino oils. I switched to synthetic to stop it and try to remove some of it. Here is a shot of my S at 50K miles using Mobil 1.



Here is a copy of an article by the American Society of Mechanical Engineers:

Abstract
Varnish formation, generated in a spark-ignited engine operating under various modes of speed, temperature, compression ratio, spark-advance, and air-fuel ratios, was investigated to establish the interrelationship between fuels, lubricants, additives, and engine operating conditions with respect to their effect and contribution to varnish deposition. The varnish precursors were identified to be primarily fuel aromatic compound. A series of engine tests was then conducted with blends of fuel aromatics and alkylate to determine their varnishing proclivities. Thus it was established that the varnishing characteristics of fuels are dependent not only on the total aromatics but even more so on the individual compounds. It was also determined that finished lubricants act as varnish inhibitors and thus determine to a high degree the engine varnish formation. On the other hand, of all engine variables, only the compression ratio and jacket temperature were found to be also of importance, although their total effect on varnish formation was smaller than that of the fuel or lubricant. Subsequently, the varnish deposits were removed from the engine parts, and a chemical analysis was made using modern instrumental techniques. The results showed the engine varnish composition is mostly alkane in character and contains condensed hydrocarbons, hydroxy-containing organic compounds, as well as ketones and nitro compounds. In addition, it was established that lead salts are also part of varnish but are not a prerequisite to varnish formation. Knowing the chemical composition of the varnish precursors, the composition of the varnish deposits, and the engine conditions under which these deposits were obtained, the chemical mechanism of varnish formation was defined by means of chemical equations. The final analysis of varnish formation is shown in the form of a computer-derived mathematical equation defining the relative importance of all variables affecting engine varnish deposition. Data are provided which show that piston varnish formation is a chemical process which occurs on the piston rubbing surfaces as the blowby travels from the combustion chamber to the engine sump.

Copyright © 1969 by ASME

 

Cosmo, great explanation! I haven't seen that buildup & varnish in years. I used to use Kendall GT-1 (mineral based) in my old BMW 2002s. It left a greenish tint on the valve-train. Maybe, from moly additives. (?) I too, have been using full synthetic oil since 1990s.

FWIW... I would not run any additives (like Seafoam or such products), but rather have the owner do some early oil changes (along with oil filter). Should look fine after a couple change-outs. Use synthetic oil, afterwards.