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#1
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2 New Engines & High Temps
So I recently replaced both my 40 year old past TBO IO 360Gs with factory remanufactured IO 360 GB2Bs on my 1977 Reims F337G. I had a cracked cylinder in the rear and that led us down the rabbit hole of seeing the badly worn cam lobes and... It was a tough pill to swallow but I hope to enjoy these engines for a long, long time.
I am 15+ hours into the break in process and still seeing what I consider to be alarmingly high CHTs, particularly during TO. We did have a baffling issue in the rear that has just been fixed but didn't seem to make much of a difference. I need to have my cowl flaps full or partially open ALL THE TIME which doesn't seem right, especially considering that It is NOT hot up here in Ontario Canada these days (just above 0C). Here is the data from my last flight: https://savvyanalysis.com/flight/280...7-d01a7f6f5daa I just really need to ensure that I am not missing anything and that I am not damaging these valuable engines that I will be paying off for quite some time. Perhaps there are some greater minds than mine who have some valuable input on this situation. Thank you all in advance! TC
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TC 1977 Reims Built F337G CYFD 
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#3
11-12-18, 01:39 PM
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Tom
For only 15 hours on the engines I don't think you are looking that bad. 460 F is max and you look to be around 375 F average. For break in this should be acceptable. For break in purposes all climbs should be shallow to minimize the temps and descents slow with high power settings as much as possible. Have you changed the oil yet? How much oil are you using? How are the oil temps? What does Savvy say?
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Herb R Harney 1968 337C Flying the same Skymaster for 47 years
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#4
11-12-18, 03:47 PM
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Quote:
__________________
TC 1977 Reims Built F337G CYFD
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#5
11-12-18, 03:48 PM
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Quote:
__________________
TC 1977 Reims Built F337G CYFD
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#6
11-12-18, 04:05 PM
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Quote:
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_________ John K 1977 337G CNC3
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#7
11-12-18, 04:23 PM
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Digging into this a little more, I think we should note that you're running these engines fairly hard:
Cruising at 25" - 26" manifold pressure, 2450 rpm, 3500' msl, etc. That would put you over 80% power I believe. Through all this I see that you're running 110 degrees oil temp on the front engine and 128 degrees on the rear engines which is good news. The low oil temps mean that your rings have sealed and the hot combustion gasses aren't getting by them and heating up the oil. Also, I'll bet that fixing the rear baffling helped those rear oil temps get close to the front on your last flight. How's your oil consumption?
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_________ John K 1977 337G CNC3 Last edited by kilr4d : 11-12-18 at 06:58 PM.
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#8
11-12-18, 04:31 PM
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http://www.continentalmotors.aero/ 1-800-326-0089 extension 2 Seriously...call them. Good people and they answer the phone.
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_________ John K 1977 337G CNC3
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#9
11-12-18, 08:57 PM
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Tom
I agree that a call to Continental is a good idea. Of all the vendors out there they are one of the best customer service. Your oil consumption sounds good and indicates the rings have seated well, as John also commented. I was always told not to baby the new engine on break in but also that you should vary the percent of power some as not to keep it consistent. Sounds like maybe that has been the case. I would want to see those oil temps higher if it were me and for all you cold weather flyers out there. The only way to achieve good oil temps in this season is cover plates on the oil cooler. I want to see at least 170 but hope to see 185 in the climb. If the oil doesn't reach these temps it will not flash out the moisture, very important in my opinion. What's your thoughts on this guys? I have always had to partially cover my oil coolers in the winter. I even had the cold temp baffles in the cowl and they never worked for me.
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Herb R Harney 1968 337C Flying the same Skymaster for 47 years
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#10
11-12-18, 10:57 PM
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On my engines, the ignition timing was set too far advanced, which resulted in increased CHT, while EGT was normal. Resetting the ignition timing on the magnetos to the correct value remedied the problem.
SavvyAnalysis was of great help in getting me an understanding of the problem, though my mechanic (Jay from Jay's Aircraft at John Wayne Airport KSNA, a real long-time pro, and also a pilot) came to the exact same conclusion without any prompting from me. Dan
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#12
11-13-18, 08:05 AM
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Quote:
__________________
TC 1977 Reims Built F337G CYFD
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#13
11-13-18, 04:59 PM
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I agree with Herb on oil temps. I've been covering my oil coolers in the winters for almost 2 decades now. Same engines all along. Temps below 50F equals one piece of duct tape across entire cooler covering about 50% of the cooler. Temps below 35F equals two pieces of duct tape covering about 90% of the cooler on the front and about 80% of the cooler on the rear. Temps hang out around 180F all the time. Cold oil is not good in my opinion for the exact reason Herb mentioned.
You can easily experiment with how much cooler to cover. If you cover a little too much, its an easy matter of reducing power somewhat and coming back down and readjusting. My bet is that won't happen though. My oil temperatures have always been more of a challenge to get higher. Ed
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#14
11-14-18, 09:01 AM
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Oil Temps
I think you need more investigation before you start obstructing the oil cooler. Is winter weight oil being used or a multi-grade? Where is the oil temperature probe located; cooler inlet, cooler outlet, someplace else? There is often a large temperature difference between the temperature at the probe location and true temperature at the outlet of the engine. Also interesting ....the highest oil temperatures occur post landing! CHT Temps I agree, I'd be concerned about the CHTs. The cylinders are big chunks of finely machined metal and need several minutes to cool down. After take-off, climb and transitioning to cruise, I'd suggest taking more time before leaning and closing the cowl flaps. The rear engine is showing a large spread of CHTs, which results in a large variation in fuel flow to each cylinder. Cleaning CHT1 injector will result in more fuel flow, and will decrease CHT1. EGTs EGTs are showing good combustion on on cylinders. There's a wierd behaviour on front EGT2 (temp decrease on start-up???).
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#15
11-14-18, 12:22 PM
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My JPI EDM reads from the front of the case just below the crankshaft. This sees the oil in the motor channels and reads digitally on the JPI. Again because I have so much experience with the factory gauges, comparing the JPI probes is relative to the factory gauges. I feel like the oil is at a higher temp in the case vs the cooler. I like to see about 170 minimum on the JPI. In the winter it's pretty tough to get there even with my covers on. I run exclusively multi grade Phillips X/C 20-50W only.
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Herb R Harney 1968 337C Flying the same Skymaster for 47 years
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