Oil In Cylinder

Rob58

Rob58

Pre-takeoff checklist
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Four months after last running my IO-470 I pulled the lower plugs and found several of them covered with engine oil. Any chance this might be normal oil seepage after such a long time sitting?
 
yes but....those oily ones have valve guide wear. It will progress and you will see increased oil consumption until it becomes unbearable.
 
Rob58 said:
Four months after last running my IO-470 I pulled the lower plugs and found several of them covered with engine oil. Any chance this might be normal oil seepage after such a long time sitting?
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An overhaul or top overhaul is in you future.
 
thanks for the feedback, confirming some of my worst fears. In addition to the problem mentioned with oil in the plugs I have a couple of cylinders where the exhaust valves have a significant oil build-up around the stems. I'm guessing this is the result of worn valve guides? Now the bad news is that my engine is supposed to have only about 200 hours since "major overhaul". Something seems wrong with this. Isn't a major overhaul supposed to include new pistons, rings and valve guides?
 
Either your engine log book will show what work was done, or if you are lucky your prior owner provided you with an invoice for the rebuild that details the work that was done. At a minimum the cylinders should have been overhauled in order to qualify as a major engine overhaul. Many owners opt for new cylinders instead of overhauling the existing ones, assuming they are within overhaul limits.
 
Rob58 said:
Four months after last running my IO-470 I pulled the lower plugs and found several of them covered with engine oil. Any chance this might be normal oil seepage after such a long time sitting?
Click to expand...
4 months setting ? pretty normal If you ask me..
 
Rob58 said:
thanks for the feedback, confirming some of my worst fears. In addition to the problem mentioned with oil in the plugs I have a couple of cylinders where the exhaust valves have a significant oil build-up around the stems. I'm guessing this is the result of worn valve guides? Now the bad news is that my engine is supposed to have only about 200 hours since "major overhaul". Something seems wrong with this. Isn't a major overhaul supposed to include new pistons, rings and valve guides?
Click to expand...
I wouldn't panic, run it see what develops.
 
In a flat motor it is not uncommon to find a little oil pooled at the bottom of the cylinder after a period of inactivity. I wouldn’t do anything right now, wait and see how things go.
 
Jumpmaster said:
Either your engine log book will show what work was done, or if you are lucky your prior owner provided you with an invoice for the rebuild that details the work that was done. At a minimum the cylinders should have been overhauled in order to qualify as a major engine overhaul. Many owners opt for new cylinders instead of overhauling the existing ones, assuming they are within overhaul limits.
Click to expand...
This is part of the problem. Validity of log book entry of engine overhaul is questionable; I have not been able to retrieve invoice or work order. I am concerned about the quality of the "overhaul" and trying to figure out my best move to determine how safe the engine is to continue operation.
 
470s are famous for having valve guides wear out. But not at 200 hours. And with Continental's push rods on the bottom of the cylinders it's unlikely oil seeped in from sitting. I'd be suspicious about how the cylinders were inspected and serviced at overhaul.
 
I would think that the logbook entry should include a description of what was done during overhaul procedure. Mine does, takes up two pages in the log. I don't know about the invoice/workorder. But I would think that it should be included with the aircraft records. Mine is also in a folder along with every other mx invoice since new. A very fat folder, along with 3 legal size manilla envelopes, and 2, 3", 3 ring binders full of stuff.
previous owner was meticulous about keeping records, to the point of being a "hoarder". Hoarder is a good thing when it comes to aircraft records. ;)
 
bluerooster said:
I would think that the logbook entry should include a description of what was done during overhaul procedure. Mine does, takes up two pages in the log. I don't know about the invoice/workorder. But I would think that it should be included with the aircraft records. Mine is also in a folder along with every other mx invoice since new. A very fat folder, along with 3 legal size manilla envelopes, and 2, 3", 3 ring binders full of stuff.
previous owner was meticulous about keeping records, to the point of being a "hoarder". Hoarder is a good thing when it comes to aircraft records. ;)
Click to expand...
The log book entry was very generic. While the entry does include "new valve guides" and some other detail, I question if this work was really done or done properly. I say this because other major components that were reported in other log entries as "overhauled", were in fact not overhauled. I am attempting to find the work order or specific documentation referred to in the log book entries however I have had no luck so far. Very few 337's were filed. As for the previous owner (now deceased) he apparently did a lot of his own maintenance work with friendly A&Ps signing the logs - maybe with oversight, but I have no way of knowing. The collective sum of everything I know about the aircraft, the records, the 337s recorded by the FAA and my observations about the condition of various components leads me to believe that maintenance was not up to my standards and possibly very deficient. I am very OCD about every maintenance detail - the former owner simply was not. I am pretty much on my own. So when I found the oil in the cylinders and on the valve stems I set out to educate myself on what is normal and what is not. I really appreciate all of the feedback!
 
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