O470-r oil viscosity?

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Johnbo

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Johnbo
I’m new to owning an O470-r and as we head into summer am thinking ahead to oil choices. I normally run Phillips XC20-50 + camguard but given that these engines were not originally designed around multi viscosity oils I’m wondering if I should go straight weight in the summer?

anyone here ever have or see issues with oil pressure on warm months running XC20-50 in this motor?

thx.
 
I get lower oil pressures right around the 30psi mark +/- 2 in the warmer months running aeroshell 15W-50. Not sure that it would be worth changing oil.
 
Phillips XC 20-50 seems to be a standard for O-470 operators, and we also use it. We get 45 to 50 PSI depending on the oil temps, which tracks closely to OAT.
 
your choice of oil + camguard is very good already. i live in Tennessee and have been running Aeroshell 15w-50 + camguard in my 0470-R as long as i've owned it (3 yrs) and previous owner did too for a while (not with camguard). I recently asked my A&P should i change to W100 for summer, since i just did my annual. He said no and stick with what i'm using. I think some A&Ps like the thought of sticking with same oil as long as appropriate for temps/engine.
 
Multigrades like 20W50 serve the purposes of two viscosities. It acts like an SAE 20 (Aviation 40) when cold, so the engine gets oil pressure real quick. Thick oil doesn't want to move quick. It acts like an SAE 50 when hot (Aviation 100) so it doesn't get watery when hot and lose its ability to keep the moving parts apart.

upload_2021-4-23_9-33-49.gif
 
I assume the data for that chart was generated using fresh oil; any idea how / if it changes after the oil is in service for a while?

Dan Thomas said:
Multigrades like 20W50 serve the purposes of two viscosities. It acts like an SAE 20 (Aviation 40) when cold, so the engine gets oil pressure real quick. Thick oil doesn't want to move quick. It acts like an SAE 50 when hot (Aviation 100) so it doesn't get watery when hot and lose its ability to keep the moving parts apart.

View attachment 95759
Click to expand...
 
Johnbo said:
I assume the data for that chart was generated using fresh oil; any idea how / if it changes after the oil is in service for a while?
Click to expand...
The viscosity modifers break down after a while, but 50 hours is no problem. You'd run into those issues more with cars whose owners change the oil every 10,000 miles whether it needs it nor not....

I ran the whole flight school fleet on Aeroshell 15W50, 50 hours between changes, with all engines reaching TBO with no problems. When we had Cessna 150s I used W80 in them; they seemed to burn more of the 15W50. And the Lycoming anti-scuffing additive in the 15W50 could sometimes cause the O-200's starter clutch to slip. Too slippery, that oil. In my A-65 it dropped the oil temps about 30 degrees just by cutting the friction so much.
 
Phillips makes Victory 20-50 now, which has anti-corrosive and anti-scuff additives like Aeroshell’s Plus oils. Camguard and X/C is my choice in my Cessna and has been for many years. If it ain’t broke? Don’t fix it. I do wonder about blending a quart of Phillips anti-rust with XC. Adding Camguard is simpler and has easy to view test results, so no guessing.
 
We started using Phillips X/C 25-60 during the summer. It is approved in the Continental engine manual and seems to work well.
 
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