A lot of things have happened in my life recently and I haven’t had a lot of time to get back on the track. But a few years ago, I had to have a new valve guide installed in one of my cylinder heads, and when I removed the head to take it to the machine shop, I was disappointed to find that the cylinder walls were worn smooth (no visible hone) where the piston tends to be pushed into it due to the angle of the connecting rod.
I wondered for a long time how this could happen. I thought that maybe the fit of the pistons was incorrect; an issue that is somewhat common with some forged pistons which leads to piston slap. But my pistons are hypereutectic which I specifically picked so this wouldn’t be a problem. So I don’t think this was the case.
Then I thought that maybe I have a fairly long stroke with a short rod producing a lot of lateral pressure into the cylinder wall. After all, my engine is a 383 stroker. But this engine combo has been done thousands of times, and I couldn’t find any evidence of this being common.
Finally, I discovered that diesel engine sometimes have an issue with this kind of cylinder wear. I discovered that diesels are more susceptible to carbon buildup and that carbon is naturally an abrasive. This carbon builds up on the top ring and actually wears away the cylinder wall.
Then it hit me. I have known that my engine has ingested a lot of oil while racing. In high ‘G’ turns, oil accumulates in the valve covers and then gets pushed thought the PCV system into the intake. My intake has always been very oily and the amount of carbon buildup in the engine was obvious when I had the head off. It was then clear to me that I was experiencing the same issue that diesel engines have – carbon buildup on the top ring that was wearing down the cylinder wall.
I have since installed two catch cans, one on both sides of the PCV system. When I ran a track day, I was shocked at how much oil I collected. I also thought that the Can I have on the side that goes from the valve cover to the plenum was going to have more oil, but it was actually the side the side that draws fresh air before the throttle body.
I know that the damage has already been done and my compression has suffered; I wish I installed these from the get-go. I never noticed any smoke from my car; though, I did know it was burning some oil during track days. After a 30min session at The Autobahn Country Club, I had collected about 3/4 of a cup of oil. I had no idea that much oil was being pushed into the intake.
Here is a link to the cans I installed. Ruien 0046 Polish Baffled Universal Aluminum Oil Catch Anything should work, I thought this one had a good price and size.