Ferrari Mailing List: Analyzing valve deposits

[Peter Rychel (dino308gt4]

I’m aware of companies that will analyze used engine oil, but is there any facility that can analyze the deposits on valves?

 

This has been an off-and-on project for me, but my GT4’s engine had not been running good and was really down on power. When I stuck my borescope camera down the spark plug holes, #7 cylinder showed vertical scratch marks, indicating broken rings (oh lovely...). So, I’m pulling the motor out.

 

I have most of the components off and got a chance recently to pull the front exhaust manifold off first. I was quite shocked to see how white the tubes were inside. I showed my coworker, but he says that’s a good sign my fuel mixture is pretty close to ideal. Now, when I looked into the exhaust ports, I was quite alarmed to see how much deposits are on the exhaust valves. I’d really like to know what is causing this. Is it the fuel? A possibility as I have on occasions run a mix of avgas & pump gas through this. Is it engine oil blow-by? Or something else?

 

I have yet to remove the rear manifold off, so it’ll be interesting to see if I see the same conditions.

 

Peter

 

 

 

 

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