Scott Hersha
Well Known Member
I’m trying different things to try to get my oil temps up to what it seems they should be, and it is a challenge. I have a newly finished RV6 with an O-360-A1A, carbed, standard compression. My oil cooler is the 7 row one you get in the FWF kit from Vans. I have it mounted on the firewall, fed through a 3” SCAT tube connected to the #4 aft baffle. The engine is new, just past breakin at 50 hours. On my first several flights with this setup the oil temp was always 175-185 after flying for 20 minutes or so. The OAT at that time (early September) was usually in the 80-90* range. Now that fall/winter is here, and the engine is broken in, I’m having a tough time getting the oil temp back to those early levels, in fact it seems to be impossible. I started with a blocking plate on the forward side of the baffle opening for the SCAT tube that was fashioned to help also cool #4 CHT. It actually helped reduce the #4 CHT just a little, but didn’t make a noticeable difference in oil temperature, see first pic below:
Then I made a flat plate instead that blocked off 1/2 of the 3” opening. That helped a little, but on a cold day (OAT in the 30’s), I still couldn’t get the oil temp above 140. I don’t have a picture of that one, but I then made a plate that covered 2/3 of the 3” opening - see below-
That one made no noticeable difference over the previous one. If the OAT was in the 50’s, I would see oil temp of about 160, but on a cold day I couldn’t get more than 135-140, depending on what I was doing (acro). So, my latest solution pictured below, is a plate that completely blocks the opening with a 1” hole drilled in the middle of it. I flew yesterday with OAT at 3500’ at 33*F. My oil temp got up to 150-155 after flying for about 30 minutes at 65% burning 8.5gph. When I came back to the airport I did some touch and goes. During this exercise, my oil temp dropped back down to 135-140.
My next step will be to tape over the 1” hole in the plate to see what happens. I’m also going to pull the oil temp probe and test it, but I’m not hopeful I will find anything wrong. I had the same issue on my RV4. I tested the probe (same GRT probe) and it was fine. I put one of those cockpit adjustable Venetian blind blockers on the -4 (front side of the oil cooler feed) and with it completely closed, I couldn’t get it to even 160 in the winter.
My CHT’s all run in the 320-340 range and within 10-12* of each other at cruise speeds. This is strictly an oil temperature issue. Can anybody see anything I might be missing?
Then I made a flat plate instead that blocked off 1/2 of the 3” opening. That helped a little, but on a cold day (OAT in the 30’s), I still couldn’t get the oil temp above 140. I don’t have a picture of that one, but I then made a plate that covered 2/3 of the 3” opening - see below-
That one made no noticeable difference over the previous one. If the OAT was in the 50’s, I would see oil temp of about 160, but on a cold day I couldn’t get more than 135-140, depending on what I was doing (acro). So, my latest solution pictured below, is a plate that completely blocks the opening with a 1” hole drilled in the middle of it. I flew yesterday with OAT at 3500’ at 33*F. My oil temp got up to 150-155 after flying for about 30 minutes at 65% burning 8.5gph. When I came back to the airport I did some touch and goes. During this exercise, my oil temp dropped back down to 135-140.
My next step will be to tape over the 1” hole in the plate to see what happens. I’m also going to pull the oil temp probe and test it, but I’m not hopeful I will find anything wrong. I had the same issue on my RV4. I tested the probe (same GRT probe) and it was fine. I put one of those cockpit adjustable Venetian blind blockers on the -4 (front side of the oil cooler feed) and with it completely closed, I couldn’t get it to even 160 in the winter.
My CHT’s all run in the 320-340 range and within 10-12* of each other at cruise speeds. This is strictly an oil temperature issue. Can anybody see anything I might be missing?
Last edited: