G
Geoff
Hello all,
I'm looking for some opinions and perhaps suggestions that I haven't thought of yet. I've read all of the threads on here (and the RV list) about temperatures and cooling.
I have 31 hours on my RV-8. It has a 180 HP Mattituck TMX-IO360 with dual P-mags. I have replaced the vernatherm, and I have replaced the Vans-supplied Niagra 20002A with a Stewart Warner 8406R. I have cut the cowling exit so it is about 1" in front of the firewall. The baffles are sealed up tight, and the inlet ramps are glassed in on the ends.
Here is some sample data from the other day:
Takeoff with a direct climb to 8500 MSL at 115 kts IAS. OAT 70F at takeoff, decreasing to 55F at altitude.
Oil temp peaked at 218F in the climb, CHTs peaked at 370F.
At 8500 MSL, I flew for an hour like this:
Then I decended to 7500 MSL and flew for an hour like this:
My oil temp is manageable right now, but it won't be next summer if nothing changes. So far I've flown with ambient air temperatures ranging from 45F-80F, and the oil temp seems to vary more closely with CHTs than the air temperature. I never get CHTs over 400F and they usually peak at 370-380F, so I don't think I have an airflow problem related to the baffles.
So... Here are my thoughts (in order of preference based on ease of the solution):
1. Do nothing until the engine gets more time on it and see what happens.
2. Cut another few inches off the cowl exit so it's 3" in front of the firewall.
3. Put some louvers in the sides of the cowling.
4. Get a bigger oil cooler.. A friend flying a similarly-configured RV-8A has a Niagra cooler that is an inch wider than my SW, and he's never seen a temperature over 200F at any time. This would require rebuilding the back baffles, though.
Have I missed anything?
Thanks.
-Geoff
I'm looking for some opinions and perhaps suggestions that I haven't thought of yet. I've read all of the threads on here (and the RV list) about temperatures and cooling.
I have 31 hours on my RV-8. It has a 180 HP Mattituck TMX-IO360 with dual P-mags. I have replaced the vernatherm, and I have replaced the Vans-supplied Niagra 20002A with a Stewart Warner 8406R. I have cut the cowling exit so it is about 1" in front of the firewall. The baffles are sealed up tight, and the inlet ramps are glassed in on the ends.
Here is some sample data from the other day:
Takeoff with a direct climb to 8500 MSL at 115 kts IAS. OAT 70F at takeoff, decreasing to 55F at altitude.
Oil temp peaked at 218F in the climb, CHTs peaked at 370F.
At 8500 MSL, I flew for an hour like this:
21.5" (WOT) and 2300 RPM.
EGTs 150 ROP (1240-1260).
CHTs 345-360F.
Fuel flow 10.8 gph.
Oil temp 210F.
OAT 55F.
Then I decended to 7500 MSL and flew for an hour like this:
20.0" and 2300 RPM.
EGTs 25 LOP (1325-1375).
CHTs 305-330F.
Fuel flow 6.4 gph.
Oil temp 190F.
OAT 57F.
My oil temp is manageable right now, but it won't be next summer if nothing changes. So far I've flown with ambient air temperatures ranging from 45F-80F, and the oil temp seems to vary more closely with CHTs than the air temperature. I never get CHTs over 400F and they usually peak at 370-380F, so I don't think I have an airflow problem related to the baffles.
So... Here are my thoughts (in order of preference based on ease of the solution):
1. Do nothing until the engine gets more time on it and see what happens.
2. Cut another few inches off the cowl exit so it's 3" in front of the firewall.
3. Put some louvers in the sides of the cowling.
4. Get a bigger oil cooler.. A friend flying a similarly-configured RV-8A has a Niagra cooler that is an inch wider than my SW, and he's never seen a temperature over 200F at any time. This would require rebuilding the back baffles, though.
Have I missed anything?
Thanks.
-Geoff
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