I was having a conversation with somone about oil the other day. He prefers Quaker State oil, and I prefer Mystik. I mentioned that I had UOA's come back good for the Mystik. He comes back by stating that the wear metal is probably going out the exhaust valve.

That got me thinking. I dont think a UOA would see wear from the valve guides, or even the upper cylinder. Most of that would wind up in the combustion chamber, and be sent out the exhaust valve, never to see the oil.

Is it possible that a UOA that returns good UOA numbers would have poor valve guide or upper cylinder wear?

 

Rusty, that is an interesting question! We could all give our own opinions, but if 5 of us responded, I'd bet all 5 of us would contradict ourselves, as laymen. My suggestion would be to pose this question to someone at Noria, or one of the oil trade publications (Lubes N Greases, Machinery Lubrication etc.) Go to: www.LNGpublishing.com or www.machinerylubrication.com These two sites will give you the correct info. If you find out anything, please write back, as I would be interested in knowing the correct answer to your question. ED

 

Sorry I couldn't answer sooner but I got hit with a Windows destroying virus. I'm back!!!!!!!!!!!! Anyway, you would be correct that some of the wear metals are going to go out with the exhaust, but not all. Quite a few will be trapped on the oily film of the cylinders and be washed into the oil. What you may not be aware of though is that a spectroscopy will not show MAJOR wear metals such as an engine that is grinding its way to oblivian. The test involves the gassing of a prescribed amount of sampled oil. The gases are then exposed to metered light and the colors that are emitted from the gases are read by the computer and the analysis report is written from that. Any MAJOR sized particles will not gas and therefore- not read. A particle in the 100 micron size won't appear on the report although it is a particle large enough to do damage if not filtered out on the first pass. If you suspect that you have internal engine damage occurring, get a particle count with the report. It will break down how many particules and what size. If the particle count is high on large particules, you would then get a ferrography test run and that will tell you how much, how many, exactly the composition, and generally, where the particules are coming from in the engine, such as rings, main bearings, cam bearings, etc. A ferrography test at most labs is not a cheap date, however. Figure $100.+ at most places. Two ways to look at it- spend the $100.+ bucks and MAYBE save an engine from total destruction OR just figure on rebuilding and put the dollars spent on ferrography into the rebuild. Most choose rebuild.