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#2 running hot and high oil temp

RicoB

Well Known Member
Patron
its's an 9A with a O-320 E3D / MT C/S electric prop, Just trying to get any tips on solution for hotter number 2, it's usually 15-20 degrees hotter than 1,3,4. others are around 385 and #2 is above 405, on a climb i see up to 425. I have already removed the front dam completely. also my oil temp is running about 210-215, my oil pressure is at 60psi at running temps, if i raise the oil pressure the oil temp goes up, if i lower the oil pressure down to 45 it runs around 185-190. Looking for ideas on how to attack this problem.. thanks
 
How many hours on your plane? Is this a newly flying or newly acquired?


Awaiting better understanding . . . I think my 7 cools pretty well (180 hp/mags) with a nice plenum and sealed tightly. But . . . I can get a CHT over 400 if left at full throttle, high RPM, and climbing at low speeds with high VS. The oil temp does not get over 190 unless KIAS drops (w/altitude) as VS begins to back off. No cooling jets on the pistons. (yours?)

So - the back of #3 and front of #2 have some restricted fins. That would help, but the elevated oil temps indicate a lower than ideal upper chamber pressure. My Vans cooler is quite adequate. Checking for engine baffle leaks is in order, esp around the inter cylinder baffle. Mine had 1/4" leak around the perimeter. Edit: Also look where the rubber meets the cowl, make sure there are no wrinkles and/or gaps.

One more item, some have had issues with the o-320 carb being too lean in full power climb. What is your full power take-off fuel rate - other 9 owners can compare and give a comparison.

edit 2: Here is how I modified the baffles for better cooling on #2. A friend drilled 5 #30 holes there to get more cooling, he got 10 deg.
JPX6LzdMijWv5ahFc08epGp5Ki3WdHf77fayHhsdwIH5MWtliid3fvwAhU0F7kMkDiiQy7FGNJSFZKiTapS0qhmt3kUU5vRfC4QpCcRVOsBvELA2aZIYF3K4AtCSDlUrbSrCC9OexwsxMxTZWAg0g0B3hrt-ILNjAQ1SMPuIkj3OQUUdX-2-r4WE9j9vouB-UTxgwZ8fUmqYMY6INDATwU4b-Dtxr7kErlQgJRT0_iFbQgSkExi1Pn0GLEAJPjDu3SrSFkbK2BQxGTQw6NJ9nYqqO7w-bMifByakZV_jyDekxVnlyc836K5rHaa9MoZy1QBXwgEgNzLK2S0JmJBNps1sptBkI58OFijVk6mw_XvzhxZAidoDi-58TZrTmSIwKtwTKjevioHvJmxIKdN7tsc9oZsDxQUqCxPTYIibBPIl7lUc5san4GcvQ2CyuxGVJIuVj47TYZGpdYhFL6oAFQr7Vdhod6I5Pq_3YoAwfoyryjeQ8xTOVHhGO1kc3UGhmpLrSZsGr7c6eW0_I9YpIY2oM4qEg36YESxYXrb1-sCs8Q8jx6n_TZQ2N_4lSkycz5IzbYOkqoxPPak_F6_DpXyEvgcEUAZPk3GQVCzdVbLK4T6a5mpaEqqmTng323tb0XaMwKukSDyDooM8h62fPJAF0n9-Oo0b=w546-h728-no
 
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Rico,

First, is this a fairly new problem or has #2 always run hot? If it has only recently been running hotter than the others that implies (as Bob pointed out) that #2 is running lean. If you have EGT you can check this by leaning the engine in flight and noting which cylinder peaks 1st. If #2 peaks 1st OR never peaks and just goes down in temp as you lean, this would confirm that #2 is running overly lean and an air intake leak is worth looking for. If one of the other Cylinders peaks 1st, the problem is probably more related to cooling than fuel/air mixture.

If #2 has always run hot, it could be running too lean or it could be a cooling issue. Check for gaps around the #2 cylinder baffles.

The oil temp issue is only partly related. As you already know the Lyco uses an adjustable pressure relief valve to regulate operating pressure. Excess oil is diverted back to the sump to maintain pressure. The higher you set the operating pressure the more oil goes to lubricate and cool the engine. The lower you set the pressure, the more oil is recirculated back to the sump without being heated by the engine. So, the higher oil temp with a higher pressure set point is normal.

If it were me, I would fix the cylinder #2 temp issue 1st. If you bring #2 CHT down, either by enrichening the mixture to that cylinder or improving cooling airflow, oil temp should also come down (at least a few degrees). If oil temp remains higher than you?d like, then you can look at oil cooler airflow.
 
So let me describe a lil more. Thanks so far for all of the info. It?s just a lil over 40hrs, I am running dual p-mags (the jumpers are not cut)
So the EGT on #2 will peak before the rest if I am leaning. I checked compression few hrs ago and that shows good, 80/80
On take off my fuel flows shows 11.3 I am still working on the accuracy of the red cube.
 
So you confirmed #2 is running leaner than the others. Check all those induction hose clamps for leaks.
Your take off fuel flow, if correct, is too low.
 
So what fuel flow should I be having at take off ? It?s a 160hp.
Could the P-mags at the 35 degree curve be cause of any extra heat? (Oil temp)
Also someone and the book mentioned the 60psi is low for pressure, what are the average pressure everyone is running on a O-320 -160hp
 
So what fuel flow should I be having at take off ? It?s a 160hp.
Could the P-mags at the 35 degree curve be cause of any extra heat? (Oil temp)
Also someone and the book mentioned the 60psi is low for pressure, what are the average pressure everyone is running on a O-320 -160hp

Assuming your CS prop is at redline, takeoff fuel flow should be around 15 gal/hr (check Lycoming spec sheet for exact number). 35 deg advance will also raise CHT.
 
... Could the P-mags at the 35 degree curve be cause of any extra heat? (Oil temp)

P-mags are known to have an aggressive curve at high MP. It very certainly could be a contributor. Easy to check though- just retime the ignitions a few degrees after TDC and fly. The timing process on Pmags is so easy it should take you 5 minutes to make the change.
 
Hot #2

I am currently dealing with the same issues of a hot #2 on climb.
0320 160 hp. Fixed pitch prop. One Lightspeed elec mag. Seeing also 11.2 gph on climb out. According to the Lycoming chart, at sea level I should be seeing 13+ gph.

Question: if the timing was a problem, wouldn?t all four cylinders be running hot?

I drilled out my jet from 42 to 41 (3k) and only saw a small amount of flow increase.
The carb company suggested I maybe had a restricted air flow issue. I experimented with removing the air filter for a flight and the flow went to 13.5 gph and all cylinders cooled way down. I modified my air box entry to make it larger as well as opened up the snorkel air intake port. I really thought this mod was going to fix the issue. It did not.

My next game plan is to time the mag with a timing light. Klaus at Lightspeed says it should show 40 deg. I ordered the SDS intake flange mod so that should deal with any intake leak. If none of this works I will drill out the jet to #40 (another 2k).

I will keep you posted with this same issue. Also, your Engine is no longer concidered an E (150hp) series as it is now a D (160 hp).
 
Ok I will try to fly without the air filter. See if that changes the fuel flow and temp.
 
Air filter

Rico. I’m sure it will. Keep in mind, these are Venturi carbs which means when you increase air flow it will also suck in more fuel. You will most likely run to rich when you do this. I had to lean to best power (max rpm) on the ground at sea level and also full power take off.

I’m using a standard Van’s air box with the standard size filter. Because of my experiment with decreasing potential air restrictions my deduction is airflow may not be my issue. I am systematically trying to solve this problem. My #2 is also first to peak while leaning. So maybe I have an induction leak. Not sure.
 
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Rico. I?m sure it will. Keep in mind, these are Venturi carbs which means when you increase air flow it will also suck in more fuel. You will most likely run to rich when you do this. I had to lean to best power (max rpm) on the ground at sea level and also full power take off.

I?m using a standard Van?s air box with the standard size filter. Because of my experiment with decreasing potential air restrictions my deduction is airflow may not be my issue. I am systematically trying to solve this problem. My #2 is also first to peak while leaning. So maybe I have an induction leak. Not sure.

Standard Lycoming engines are designed to run rich of best power at takeoff, to aid in cooling and detonation protection. You lean for takeoff at sea level at your own risk.
 
49clipper

My fixed pitch 160hp O-320 burns 12.5 at takeoff turning 2250 initial ground roll. fuel flow goes up with rpm of course. see 13.5 at 100mph climb. never ever see over 360f cht. Check your fuel flow and intake gaskets.
Jim
 
Sounds like running without the air filter is not going to fix my problem. Because the filter has to go back in
 
its's an 9A with a O-320 E3D / MT C/S electric prop, Just trying to get any tips on solution for hotter number 2, it's usually 15-20 degrees hotter than 1,3,4. others are around 385 and #2 is above 405, on a climb i see up to 425. I have already removed the front dam completely. also my oil temp is running about 210-215, my oil pressure is at 60psi at running temps, if i raise the oil pressure the oil temp goes up, if i lower the oil pressure down to 45 it runs around 185-190. Looking for ideas on how to attack this problem.. thanks

Rico - a couple thoughts.

15-20 degrees warmer than the others is really not much. A very small difference in fuel/air mixtures from one cylinder to the next can easily do that. Comments here about one cylinder running "lean", therefore it is hot, could be somewhat misleading. A lean cylinder could also cause it to run cool, it just depends on where along the rich-lean spectrum you happen to be.

As others have noted, if your fuel burn is only 11 gph on WOT/max rpm, that is a problem likely separate from the temperature difference you've noted.

One cylinder's egt (and cht follows a similar pattern) will always peak first and one will peak last, the only question is how much total fuel flow difference is there between those. I didn't see any confirmation, but do you have a carb? Also, is your fuel totalizer showing the correct amounts at fill-ups?

There are many, many threads on this subject, all good reading material. Verify and fix the low fuel flow at wot, and then do the "gami spread" data collection and report back. This is where you establish, e.g., 24/2400 level, and start very rich. Gradually lean by .1 or .2 gph until the engine has lost a lot of power and is likely running rough. Pause about 30 seconds between each setting to allow temperature stabilization. The rough running as you have passed lean of peak is due to each cylinder putting out different amounts of power (assuming non-uniform mixture distribution). This test will tell us a lot of information.

Re the oil pressure, as others noted it should be set higher than what you've reported. Sometimes a different spring is needed to enable adjustment within the 80psi range. I think Lycoming makes 3 different ones, color coded.

I have no opinion as to why the temperature and oil pressure would be inversely correlated.
 
Alex thank you.
I will def check the accuracy of my FF within the next fill ups. Mine is not fuel injection so I can?t fine tune each cylinder.
So my 60psi oil pressure is low, I want to raise it but the oil temp goes up. Is there any difference in changing the springs or adding washers to adjust the pressure? I did the washers.
 
Alex thank you.
I will def check the accuracy of my FF within the next fill ups. Mine is not fuel injection so I can’t fine tune each cylinder.
So my 60psi oil pressure is low, I want to raise it but the oil temp goes up. Is there any difference in changing the springs or adding washers to adjust the pressure? I did the washers.

non-adjustable caps use washers and the adjustable caps require only turning the external adjustment nut. If you have the former and already have more than 2-3 washers, you probably need a new spring.

Larry
 
Yes I have 3 washers now, and puts my pressure at around 60psi. It if I raise the pressure my oil temp goes up into the 215/220. Also I dropped to 60 and Stay as low as 205/210
 
Yes I have 3 washers now, and puts my pressure at around 60psi. It if I raise the pressure my oil temp goes up into the 215/220. Also I dropped to 60 and Stay as low as 205/210

You need to get the pressure up from the minimum, period. You can then take remediation steps to get the oil temps down. While there is cause and effect here, there are other ways to lower your oil temps. Baffling improvements may help, or possibly a bigger cooler. Do some searching and start a new thread on reducing oil temps. Many have traveled that road.

If you have three washers, I suggest buying a new spring as it probably has lost some of it's temper.

Larry
 
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