You definitely do not want Camguard during the break-in.
After that, it is recommended to use 100% mineral oils, no synthetic oils, i.e. no Aeroshell 15W50. I switched to using it with straight mineral 100 in summer and Philips 20W40 mineral multi-grade in winter. While Philips X/C is mostly unknown in Europe, it actually doesn't cost more and is supposedly superior to the 50% synthetic oils we normally use (Total, Aeroshell, Exxon).
"Despite the sample being 47 hours old (longer than my usual) it clearly shows that Camguard achieves astonishing reductions in iron, nickel, copper and chromium. Oddly enough aluminium is not affected."
Camguard does not directly provide wear protection to soft metals like aluminum. Soft metals (aluminum and bearings) are separated from steel by an oil film. Deposits impact the wear on aluminum parts by impacting the protective oil film such as sticky rings or piston pins affecting piston wear. Camguard does stop deposit formation, and therefore wear, on these soft metals.
Ed
As Achimha said you do NOT want to use Camguard during break-in of a new, overhauled or cylinder overhauled engine. I recommend changing the break-in oil at 5-6 hours and again in 15 more hours and then starting on Camguard.
Ed
The oil analysis from the first 1 or 2 post-overhaul samples is rather scary, too 
Thanks for all your contributions Ed, I have been using Camguard in my Mooney (IO360A1A) and oil analysis over the last couple of years is definitely showing a reduction of wear despite infrequent flying over the winter. Great stuff!
This winter I am thinking of hangaring the aircraft rather than leaving it outside and flying it every month. The aircraft will be in a hangar for 3 months, and won't be flown. I still have a drum of Aeroshell 2F and thinking of using that.
Alternatively I am thinking of doubling Camguard levels as suggested on another post and flying it every 6 weeks or so, maybe sticking a engine dehumidifier if I can. Slightly more complicated but gives me flexibility in using the aircraft.
Any comments on the above welcome (Ed and others obviously!)
Speaking of oil analysis, two separate UK maintenance firms have said to me that they frequently get poor results back in the first sample sent off for analysis on a particular engine. It may of course be a coincidence but naturally if you see metal, you are more inclined to keep ordering the tests...
two separate UK maintenance firms have said to me that they frequently get poor results back in the first sample sent off for analysis on a particular engine
Which lab did they use for the analysis?
Almost nobody in the UK does oil analysis, and those who do tend to use UK labs.
I use avlab.com in the USA. I would be astonished if they were faking the results, because it would be obvious to anybody whose engine has not been anywhere near recent maintenance.
The analysis data can vary quite a bit from one sample to the next. I found that taking the oil past ~ 45hrs does increase the (pro-rated) metal values significantly, suggesting that the oil is not doing its job too well at that age. Also there may be other factors but they are less obvious. I suspect for example that one does get a bit of corrosion in the cylinders during the winter, even if flying every week or two, and this will rub off and cause a spike in aluminium. Using the common copper-loaded spark plug thread lube also produces a totally scary copper spike!
Consistency is key. You warm up the engine thoroughly, and take the sample at a fixed time (say 2 mins) into the drain oil flow.
This may be a silly question, but does oil consumption effect the cleanliness of the oil? A consumption of 1 quart per 5 hours would replace all the oil in a 9 quart sump over 45 hours, or does the dirt just build up anyway, but isn't that what the filter is for?
does oil consumption effect the cleanliness of the oil? A consumption of 1 quart per 5 hours would replace all the oil in a 9 quart sump over 45 hours, or does the dirt just build up anyway, but isn't that what the filter is for?
Yes, adding oil must affect it. I don't know if Avlab corrects for this. I don't think they do. But in general the oil consumption is relatively constant relative to the sample ("50hr" check) frequency.
This may be a silly question, but does oil consumption effect the cleanliness of the oil? A consumption of 1 quart per 5 hours would replace all the oil in a 9 quart sump over 45 hours, or does the dirt just build up anyway
The opposite is true I'd say. Oil consumption means the piston rings don't seal well and oil enters the combustion chamber and gets burned. That also means that a lot of blow-by travels from the combustion chamber to the engine case and contaminates the oil -- a two way street.
Good engines don't consume oil because they have a perfect seal at the pistons. Look at the oil of a car engine that gets replaced after 20 000km. It looks like new, better than my Lycoming oil after one hour.
