Aerovee oil Temps
https://sonexbuilders.net/viewtopic.php?f=7&t=7312
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Aerovee oil Temps
Posted: Mon Jun 26, 2023 4:50 pm
by 429TB
Hello all. I have a Waiex with the 2180 Aerovee. Purchased 3 years ago and personally flown about 50 hours in that time. The previous owner rebuilt the engine just prior to me buying it. It took almost a year for me to get it into the air and when I did I started noticing about 30 minutes into the flight the oil Temps would start to rise to over 200 degrees and could not come down with adjusting the power. . The previous owner installed a second oil sump, relocated the oil cooler to near the firewall and installed the aeroconversions air oil separator and external oil filter. All mounted on the firewall.
After several attempts to increase air flow to the oil cooler mounted ver far back under the cowling I decided to return the set up as close to the stock bottom mount oil cooler as I could. I even added a larger 19 row oil cooler vs the stock 12 row.
The question I have is currently the oil cooler, separator and filter are routed oil from an EMPI oil cooler delete adapter on the top of the engine where a top mount oil cooler goes. After hours of testing I am of the assumption that those ports do not have enough pressure or flow to move the oil through several feet of oil lines, the cooler and the filter. I believe replacing the aeroconversions blockoff plate with a plate that has oil line attachment points and routing them directly to the oil cooler could solve this problem. Looking for other possible solutions. I have been told in person to check my oil Pressure relief valve and oil Pressure control valve and ensure the aren’t sticking.
Oil Pressure is steady at idle with 30 to 40 Psi. When at flight at 2200 rpm its around 50psi and at WOT around 60psi.
Oil temps in the traffic pattern this week were sporatic and could change from 170 to 220 degrees in a matter of seconds. CHTs and EGTs are all within limits and monitored by an MGL EFIS.
I have ordered a new temp sender as i suspect it may be faulty. The sender is mounted on the lower left side of the engine sump as you sit in the cockpit.
Re: Aerovee oil Temps
Posted: Mon Jun 26, 2023 7:18 pm
by Bryan Cotton
Hi 429TB,
I’ve been going through my own oil cooler issues for a top mounted setup:
viewtopic.php?f=7&t=7279
There are two factors in play, I think. Air flow through the cooler and oil flow through the cooler.
Your pressures are good. Have you popped out and polished your front plunger? If it is stuck in the bottom of the bore then oil will not go through the cooler.
The stock Sonex oil pump for a remote cooler will send 100% of flow through the cooler:
https://www.sonexaircraft.com/eshop/car … g=Oil+pump
My sender is in the same spot. It does not change readings very rapidly.
Re: Aerovee oil Temps
Posted: Tue Jun 27, 2023 9:18 am
by 429TB
Thanks for the quick reply Bryan.
I will check both plungers/pistons in the check and pressure valves.
Do you see any issues with swapping back to the oil pump cover with two oil lines going directly to the cooler like a revmaster set up ? A fried of mine has the revmaster and sees no issues with oil Pressure fluctuations and high Temps like me.
I would probably keep the filter and air oil separator feeding off the top location and the cooler fed off the oil pump itself.
I also have a new temp sender coming just in case.
Thanks again.
Re: Aerovee oil Temps
Posted: Tue Jun 27, 2023 9:39 am
by Bryan Cotton
The one thing to beware of with the oil pump I listed is the cold start. Below 50F or so, maybe higher, you can get a big oil pressure spike on startup. I blew out my oil filter twice. I have since removed the filter and gone back to a conventional pump and used a Gene Berg 239 pressure relief oil pump cover. Before I did this, I needed to preheat to avoid blowouts. Your oil cooler would be subject to the same cold start pressures.
Check out the last 5 pages or so of this thread:
viewtopic.php?f=7&t=4030
Re: Aerovee oil Temps
Posted: Tue Jun 27, 2023 10:23 am
by 429TB
Thanks for the information.
I think I’ll try checking the valves first. Then resort to changing the pump and oil lines if that doesn’t fix it. The interesting thing is the temp fluctuations… I flew 2 patterns a few days ago. The first pattern saw a steady climb in temp to 177. On final approach, 70mph indicated it climbed to 210. On climb out on the touch n go it went to 175 then back to 220 on the down wind. I didn’t like the fluctuations so I landed, taxied about a quarter mile and it went from 220 to 230 then down to 200 by the time I got to the hangar. Very odd to me. What’s your thoughts there ?
Re: Aerovee oil Temps
Posted: Tue Jun 27, 2023 11:14 am
by Bryan Cotton
That’s a good approach I think. You can pop out the plungers with only a little oil loss. I found my Harbor Freight 1/2" center punch was a snug fit in the bore of the plunger. Good for removing them, and with a piece of tape over it I was able to chuck it up in the drill press to polish with scotchbrite. Any 1/2 metal rod would do.
Re: Aerovee oil Temps
Posted: Tue Jun 27, 2023 11:18 am
by Bryan Cotton
429TB wrote:What’s your thoughts there ?
I would be checking the wiring. My sensor is an RTD, so the resistance changes with temperature. If you have a bad connection that could give fast resistance changes. The oil has a lot of inertia with respect to changing temperature, so I doubt it is actually changing that fast.
Edit: I also had to run a dedicated sensor ground from the RTD to my Alpha MFD, else my temps would change with electrical load.
Re: Aerovee oil Temps
Posted: Tue Jun 27, 2023 12:57 pm
by 429TB
Awesome info, thank you. Is your oil Pressure wire shielded in anyway gong to the temp sensor ?
Re: Aerovee oil Temps
Posted: Tue Jun 27, 2023 2:36 pm
by Bryan Cotton
429TB wrote:Awesome info, thank you. Is your oil Pressure wire shielded in anyway gong to the temp sensor ?
I think I used twisted shielded wire to the sensor because I had it. I think from the rear of the engine back it is single conductor. I’ll have check, but it won’t be until at least the weekend.
Re: Aerovee oil Temps
Posted: Tue Jun 27, 2023 3:05 pm
by 429TB
No worries. No rush. Thanks again for the help.
Re: Aerovee oil Temps
Posted: Tue Jun 27, 2023 3:27 pm
by 429TB
After reading the threads you sent me on your airplane do you think I could cut a small amount off of my spring and bring my pressure down slightly? 60 Psi at cruise epm seems high compared to others. The more I read and watch the more I think I may have very little flow through my cooler.
Re: Aerovee oil Temps
Posted: Tue Jun 27, 2023 3:57 pm
by Bryan Cotton
My pressures were about 70psi in cruise and shortening my spring dropped about 10psi. But this is just what I did, not condoned by anyone.
If it was me I’d mess with the wiring first - dedicated signal and return to your MFD or gauge. Then polish the plungers. Then decide if further experiments were warranted.
Re: Aerovee oil Temps
Posted: Tue Jun 27, 2023 5:00 pm
by Mike53
The springs that come with aerovee engines are after market and like mine on my Hummel engine they are stiff . I went to a dedicated VW repair shop and bought original springs and that solved my high pressure problem. Pretty cheap fix.
Re: Aerovee oil Temps
Posted: Tue Jun 27, 2023 6:09 pm
by Bryan Cotton
Mike53 wrote:The springs that come with aerovee engines are after market and like mine on my Hummel engine they are stiff . I went to a dedicated VW repair shop and bought original springs and that solved my high pressure problem. Pretty cheap fix.
All the internet offerings I could find were high pressure springs. If anyone has a link to an OEM spring that would be cool. I wish I still had the two junk motors a friend gave me decades ago.
Re: Aerovee oil Temps
Posted: Tue Jun 27, 2023 9:18 pm
by 429TB
Just pulled the front spring and plunger. Spring is shiny aftermarket i assume. Plunger shows wear and didn’t come out right away. Not saying it was stuck because it did fall out about 2 minutes after pulling the plug but it looks like it could be binding up. Think that could cause the oil to bypass the cooler ? Pics attached .
Re: Aerovee oil Temps
Posted: Tue Jun 27, 2023 9:51 pm
by Bryan Cotton
Hard to say - but I think polishing it can only do good.
At zero oil pressure, like when not running, you should get max flow path to the cooler. As pressure builds it will compress the spring and reduce flow to the cooler. Does the plunger go all the way to the top of the bore?
Re: Aerovee oil Temps
Posted: Tue Jun 27, 2023 10:03 pm
by 429TB
As best I can tell it does. When I removed the bolt, about 1/2 to 3/4 of the spring was extended below the threads in the hole. The spring is very stiff. Kinda think I need to go back to the stock spring and start from there.
On another note, I found the old oil pump. The previous owner pulled this one off and put a new one on. He also added an extra oil sump, which I removed due to high oil temps, hoping to increase the air flow to the cooler since the extra sump was blocking 90% of the opening on the cowling.
Thought about changing the stock aeroconversions oil pump plate for this one and routing this direct to the cooler. Just to see if it fixes my temp problem. Then work it from there. Thoughts on that ?
Thanks again. You’ve all have been a huge help on short notice.
Re: Aerovee oil Temps
Posted: Tue Jun 27, 2023 10:22 pm
by Bryan Cotton
I’d try one thing at a time to figure out the root cause. I personally would go after wiring first. If that doesn’t change anything then that oil pump will put 100% of your flow through the cooler - eliminating another variable.
Re: Aerovee oil Temps
Posted: Tue Jun 27, 2023 10:36 pm
by 429TB
Ok. I think that’s a good plan. Dedicated ground to the RDAC and insulate the wire going to the sending unit ? And test the new and old temp sender.
Re: Aerovee oil Temps
Posted: Thu Jun 29, 2023 3:56 pm
by 429TB
I will get the wiring fixed / checked this weekend. I emailed sonex and they gave a quick reply. Their recommendation is to put the top oil cooler back on and start from there. Which I fully support doing. Only thing I will need is the cooler as I believe I have everything else. I do need to check the S/N on the adapter as they have an improved one.
I have one question before I remove everything. I have a oil pump cover as pictured above that has AN6 fittings and can connect my cooler directly to this. If I connect both ends to the pump cover and the oil pump discharge to the oil pump case is not plugged on the outlet side, will the pump provide enough oil to the cooler and engine? Or does one of them need plugged to operate properly ?
I’ll order the top cooler and other supplies tonight after confirming the SN and what else is needed.