I have tuned my engine following Mark Fuess' method and it runs great, strong on the top end with good idle and transition. My concern is the temp. At the top of the cylinder its running about 255 and 235 at the base. Is this acceptable and if not how do you lower the temp if your not supposed to back off the high needle.

Thanks
Jeremy

What engine is it, how and when are you checking its temperature?

read this, there is enough info for you
https://www.flyinggiants.com/forums/...ad.php?t=51218

Its a ZDZ 80 with the black head. I'm checking it with a quality infrared gauge. Also I Get the same temps with the cowl off as I do with it on.

If those temps are after a long down wind leg, final approach, and taxi back it sounds a little higher than I normally see on unpainted cylinders but the range you noted is what I would want my engine to run on average over the length of a 10-15 minute flight with high peaks significantly higher. If you're only sampling the temp on the ground after landing, there is no way to tell if the engine is getting to hot in the air without looking inside. Get a small temperature data logger like the Venom Racing one to see what your hitting during flight, the temps you posted are no cause for alarm.

The temps are on the ground after running it for a few minutes and shutting it off and taking the temp immediately. If I get one of the venom temp gauges what shouldn't the peak temp exceed?

350f

Any engine that is baffled half decent and has GOOD air extraction (which is actually more important I "feel") should not have problems overheating. Well unless you have it way too lean.
I have run one of the lightest engines with the smallest fin area with no overheating problems confirmed via on board temp sensor.
In air temps can very greatly from landing temps, as much as 100+*'s
Some engines can take heat into the 400's some can't, but that high of temps are not really good for any engine.

Read this page and you will know all there is to and about proper engine cooling
http://www.prme.nl/forum/viewtopic.php?p=506#506

Your fuel/oil mix can have a big effect on your temperatures also.

Yes it can.

you know talking oil, (you guy's brought it up not me). i switch from belray @ 50-1 on my bme 58 after breaking the piston rings,to pennzoil @ 32-1 and i notice a lot cooler running engine.
i really don't think the belray had anything to do with the rings breaking,but it just makes me fell a little safer at 32-1.
the piston skirt was tarnish,so i was probably to lean witch in turn raised the temp?

after you idle then shut your engine down the temps start to increase from actual running temp, get a data logger

Originally Posted by closetguy

you know talking oil, (you guy's brought it up not me). i switch from belray @ 50-1 on my bme 58 after breaking the piston rings,to pennzoil @ 32-1 and i notice a lot cooler running engine.
i really don't think the belray had anything to do with the rings breaking,but it just makes me fell a little safer at 32-1.
the piston skirt was tarnish,so i was probably to lean witch in turn raised the temp?

Most likely. I run H1R at 40:1 and it keeps the temps down great. I would assume any good 50:1 synthetic at the same mixture would do the same.

Oil takes heat from the engine...20-1 would take even more heat out....

Hi Guys,

I will bring this thread up again, as I had a little shock yesterday.
Flying my Pilot RC 35% Katana with the Eagle tree data logger. I was always wondering what temps the engine was running, so I bought the logger.
Boy was I in for a surprise. The engine is almost baffled, meaning that the front intakes are closed off so that no air can exit under, over or past the sides of the engine. Other than that the extraction has a tiny 4mm lip and a hole about the size of the intakes itself. I must admit that i did run the engine hard as you can see by the prolonged full throttle stints that where mostly knife edge eights or very large circles.
The engine is a RCGF 100cc bottom induction. It has done about 50 flights running a RCGF 27x10 prop.
Fuel is 95 Octane mixes 32/1 Stihl HP (not ultra so it mineral)

The second session is of a 35% Pilot RC Sbach running a DLE 111cc running a Mezj 27X10 TH. Very well Baffled with everything done to prevent overheating. Flown not quite as hard, but not floating around either. ( I think that it would make no difference anyway as the temp difference is so large)
Fuel used is 95 octane mixed at 32/1 Stihl HP Super.

This opened my and others eyes to how much good baffling can do.