I’m on 15w50 and Camguard, yep.
Engine runs great, and leans nicely in cruise. There is some egt split at WOT but if I bring the throttle lever back about 10mm then it evens out, so I think this is just due to the butterfly in the carb physically pointing to the rear two cylinders more. Otherwise in cruise I can get about 10F LOP before it runs rough, EGTs are quite even.
I did a low tech cam lift check when I bought it, and there were no differences between the various valves.
No metal in oil so far.
There won’t be any chance of the engine sitting unused, it’s had 83hrs added to the tacho since I first flew it in August :)
IO390 wrote:
15w50
The only advantage of 15W50 vs W80/100 is on startup. When you shutdown oil drains away from parts for longer on 15W50 than W80/100 so it protects less.
EGT split on the same flight is not a problem in itself. A trend change in EGT for each cyl in progressive flights may point to lobe wear.
Good thing you fly regularly.
Thanks for the advice @Antonio – I will keep an eye on it.
I’m coming up to 47 hours on the current oil, so I need to drop the oil and change it, plus filter inspection imminently. In that time I’ve added 3qts to top up, but about 1qt of that has been lost due to negative G, so it’s still only using about 2qt between changes. Could be worse.
As an aside, here is a view down the crank.
You can see how much lead deposit is on the inside, about 1mm thick. This is from about 600hr of running leaded fuel, I only use UL91 since I bought it.
I have scraped off the first inch or so, it is like a thick paste.
Once you get to it, you have to clean it completely since you don’t want any loose grudge to clog your oil passages, suction screen, etc
This is ingenious. I never knew the pressurised part of the crankshaft is just the front bit.
I wonder how much work would be involved in removing and replacing the 2nd plug also, enabling inspection on an engine set up for a CS prop?
Still, removing the propeller takes a lot of time…
