C85-8 redlines

[DannyDot]

I am going to mark the redlines for my C-85-8 engine.

What is the oil temp and RPM limit on this engine? I have a previous answer that the oil pressure it 10 min at idle, 30 min at cruise RPM and 60 max.

Danny Deger

[flyguy]

Re: C85-8 redlines

225F, 85 hp @ 2575, says for 5 min. (LOL) Oil 30 to 40 PSI. All per FAA E-233 Rev 17.
I had one with really big clearances (per the guy who overhauled it) that would drop to 10 PSI at idle, but hold 30 PSI at cruise.
The one I have now will idle and cruise at 32 PSI.
DC

[VictorBravo]

Re: C85-8 redlines

225F,
DC

Danny,

I have it on very good authority that the oil temp redline is based on the properties of the oil from the 1940's, which has a lot lower temperature limits than today's oils. This engineer / old piston engine expert said that today's airplane (and car) oils can run at 240-250 before any loss in lubrication properties. So set your oil redline at 225 or whatever per the type certificate , and rest easy that if the temperature goes up to 240 you're not doing any damage to the oil.

However, high oil temps are also indicative of high cylinder temps. T-crafts tend to run hot in the cylinder anyway. Take as much effort as you can to provide a good seal around your lower engine baffle (the one between the intake manifold and the bottom of the engine). Make sure all the air coming in through that square opening under the prop is NOT leaking out into the lower cowling, and not pushing out sideways under the engine. The interface between the baffles and the part riveted to the nose bowl has to be sealed up.

[Guest]

Re: C85-8 redlines

I am going to mark the redlines for my C-85-8 engine.

What is the oil temp and RPM limit on this engine? I have a previous answer that the oil pressure it 10 min at idle, 30 min at cruise RPM and 60 max.

Danny Deger

Hey Danny,

I bet you find it at the FAA website, look up the TCDS for that engine, should be in there.

Of course its in the manuls too, I am assuming you have no manuals.

Dave

[Guest]

Re: C85-8 redlines

oops!

Way wrong about that! Its not in there, or I can't find it.

link below;

http://www.airweb.faa.gov/regulatory_and_guidance_Library/rgMakeModel.nsf/0/73e923a0d5faef7e8525670e004526a4/$FILE/ATTRB7ZS/E-233.pdf

oil temp is what I am looking for

Arg!- found it in note 1

[Guest]

Re: C85-8 redlines

double arg!

and so did Darryl two days back!

sorry for the duplication and wasting your time

Dave