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Another oil cooler question

bret

Well Known Member
After hours of reading the past threads on the subject, and not completely competent in this decision, what is the largest cooler that will fit on the rear baffle of the 7a, and is the dual pass more efficient? Engine is the angle valve 200 HP with piston sprayers. I originally installed the 8 row that was in the Mooney that this engine came out of, but I don't think it is going to cool enough. Other data is a non modified James long cowl, custom plenum and diffusers, two exhaust pipes out the bottom. some have said trimming the cowl exit worked, and some didn't, some have too cool oil temps???? some did louvers and or ASA cowl flap and some had good results and some didn't. thanks for any input, Bret.
 
I think you are going to have a hard time fitting anything bigger than a 7 row cooler on the back of the baffles due to engine mount interference. I have one there and with my io-360b1b with squirters, and it is marginal for me on hot days. Thinking of going bigger and either hanging it on the engine mount or on the firewall.

Erich
 
I have a Air flow systems 13 row on my baffle sitting behind the number 3 cylinder. This is on a RV7 with my own plenhum lid on slightly modified vans baffles. I cut the rear baffle and moved it forward so it was closer to the cylinder as it would be on the other side. The cylinders 1 and 3 sit slightly further forward than 2 and 4 giving more room. The engine is the IO360A1B6 angle valve and almost never gets over 88 Deg C 90 on a 30 Dec C day. If you PM me I can send a photo. Sorry not been able to work out how to post pics
 
I know there are differences between the two but are pretty sure that upper area on the left and right sides they are close if not the same.:)
 
Hi Bret,

Just FYI - not really any advice.

I have the Lycoming IO-360-A1A (200hp). I also have the large cooler from the Mooney that my engine was removed from. I mounted my cooler on a homemade bracket on the firewall angled towards the cowl outlet and feed the cooler with a 3-1/2" SCAT tube in the general location where the cooler mounts to the baffles. Nothing fancy, but looks nice. My thinking of where I mounted the cooler came from this...........There is a mechanic in the hangar next door and he has seen a lot of RVs over the years. I have rarely seen an RV in his hangar that did not have cracking going on where the cooler mounts. Since I had the option to rethink, I chose to pt mine on the firewall to hopefully alleviate the cracking issue.

I have about 33 hours into Phase I right now and my oil temps run spot on at 179-180. I'm in the Southwest and 95 degrees is about the warmest outside air temp that I have been in at this point.

Ben
 
What is the largest cooler that will fit on the rear baffle of the 7a, and is the dual pass more efficient? Thanks for any input, Bret.

....I fabricated an offset, wedge bracket that goes in between the baffle and the cooler. This enabled me to use a 14 row oil cooler on our 9-A (same as 7-A). This cooler in a duel pass version was the very best of all seven oil coolers we tried. We actually tried single and duel pass on each configuration and the duel pass was always a noticeable improvement (5 to 10 degrees, small to large cooler). I posted photos and results here on this forum, but for the life of me I can't find them. If I find those posts or copies of the photos I will re-post them here. Thanks, Allan:D
 
Hi Bret,

Just FYI - not really any advice.

I have the Lycoming IO-360-A1A (200hp). I also have the large cooler from the Mooney that my engine was removed from. I mounted my cooler on a homemade bracket on the firewall angled towards the cowl outlet and feed the cooler with a 3-1/2" SCAT tube in the general location where the cooler mounts to the baffles. Nothing fancy, but looks nice. My thinking of where I mounted the cooler came from this...........There is a mechanic in the hangar next door and he has seen a lot of RVs over the years. I have rarely seen an RV in his hangar that did not have cracking going on where the cooler mounts. Since I had the option to rethink, I chose to pt mine on the firewall to hopefully alleviate the cracking issue.

I have about 33 hours into Phase I right now and my oil temps run spot on at 179-180. I'm in the Southwest and 95 degrees is about the warmest outside air temp that I have been in at this point.

Ben

interesting, do you have a part # for the cooler you are using. thanks.
 
Also, with the Classic Aero oil coolers, is there a major difference in the standard cooler and the HE cooler, the price is twice for the HE?
 
Also, with the Classic Aero oil coolers, is there a major difference in the standard cooler and the HE cooler, the price is twice for the HE?

Bret-
You might call Pacific Oil Coolers. They have a good reputation on this forum for helping solve problems and have a version of a HE that they could comment on I'm sure.

I'm about to explore a similar issue and that's my next step.
 
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Also, with the Classic Aero oil coolers, is there a major difference in the standard cooler and the HE cooler, the price is twice for the HE?
.
....Yes! The HE unit gets rid on considerably more heat. Call pacific, ask for Wayne, and tell him to give you the part number for the HE double pass cooler Anti-Splat-Aero tested and found to be the best of all of them on out RVs. Thanks, Allan..:D
 
Difference

There is a huge difference between the 7 and the 7A mount as far as oil cooler fitment is concerned. What may fit well on the 7A could be a pain on the 7 because of the additional brace midway. I have a brand new SW8432R cooler that will NOT fit the 7 area without major fab work. It may work on the 7A but not very well on a 7.
 
Be aware the double pass coolers, although about 10% more efficient, exhibit considerably greater oil flow restriction, which translates into more pressure against the vernatherm tip. Until the vernatherm is fully seated, some oil is bypassing the cooler.

Look at the SW "Oil Side Pressure Drop" chart for an 8432. Lycoming 4 cyl oil flow is about 7 gallons per minute, or 56 lbs, which makes the deltaP at the vernatherm more than 15 psi. A single pass cooler of the same dimensions (10599R) is about 5 psi. Same mass airflow rate.

For an angle valve, given its head finning, I'd pick a much larger single pass, in order to bias mass airflow to the cooler.
 
I'm considering the replacement of my SW 8406 (6-row/Single pass) with the SW 8432 (8-row/Dual pass). The SW 8432 is 1" wider, with the other dimensions the same, and both fittings are on one end.

I have an RV6 with a IO-360, James cowl, oil cooler mounted behind #4 on the baffle.

Has anyone had a good or bad experience with this replacement?

By the way, I spoke with Wayne this morning at Pacific, explaining my situation. He recommended the Aero Classics 8001689 which is the same at the SW 8432 (8-row/dual pass). The 8-row/single pass version is the Aero Classics 8001599 or SW 10599. He recommends the dual pass as it has slight better efficiency, same size.

$
 
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Do you need it?

Are you trying to solve a known issue? With baffling being almost free to fix, have you looked at improvements there first?
 
Are you trying to solve a known issue? With baffling being almost free to fix, have you looked at improvements there first?

I have been way down the rabbit hole to reduce CHT's and oil temperature. I've had good results as a result of the advice in these forums, but I want about 15 degrees of oil temperature, CHT's are good.

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Bret,

I have an 11 row HE oil cooler that I used the Vans firewall mount to mount on my 7A firewall. Yes I dig glup when they told me the price. I did this as a new build but I think it worked out pretty well as far as fitting and the location. Vans support got me pretty close with some information they provided.

Having said that I was able to optimize the position since I didn't have any else in that area of the firewall. That might not be the case for plane that is already flying. I'd be happy to send some pics of where I positioned it. Not to say other locations wouldn't work though.
 
Parellel valve, IO-360, 10:1, EIS, CS prop, James cowl, vernatherm removed, by-pass valve, oil to cooler controlled with ball valve. The SW 8406 puts me at 225F low altitude in Texas, this time of the year. I've seen it get close to 240F high altitude Colorado this time of year. If I cruise rich of peak, my oil temp will climb above 200F at 10,000'. LOP it will cool to 180-190F. I've done most of the stuff suggested on the forums. If I can squeeze a bigger cooler on the baffle, I'll be good in the summer time.
 
Parellel valve, IO-360, 10:1, EIS, CS prop, James cowl, vernatherm removed, by-pass valve, oil to cooler controlled with ball valve. The SW 8406 puts me at 225F low altitude in Texas, this time of the year. I've seen it get close to 240F high altitude Colorado this time of year. If I cruise rich of peak, my oil temp will climb above 200F at 10,000'. LOP it will cool to 180-190F. I've done most of the stuff suggested on the forums. If I can squeeze a bigger cooler on the baffle, I'll be good in the summer time.

Got it. I asked because, in general, the angle valve motors reject more heat through the oil. That said, a parallel valve with piston squirters will also need more heat rejection capacity.

Here is comparative data from the trusty S&W catalog, all at 6" H2O air deltaP across the fins, 55 lbs of oil flow per minute, and 100 deltaT:

8406 (single pass)
325 BTU
oil pressure drop 5.5 psi

8432 (dual pass)
400 BTU
oil pressure drop 16 psi

10599 (single pass)
375 BTU (aprox)
oil pressure drop 4.25 psi

The 8432 and the 10599 are identical size cores. The primary difference is single vs dual pass, with different hose connection locations. Obviously the dual pass cooler has a little better heat transfer.

The 8432's large deltaP across the oil side means pump pressure will hold the viscosity valve open longer during warm up, bypassing the cooler even with the ball valve open. It may raise the piston when hot. I don't know.
 
Yep, I've got that data. Thanks for sharing. The question remains, however. Can I fit the SW 8432 on the #4 baffle? I found the answer. On the RV6 the engine mount is only 1/4" from the flange of the SW 8406. The SW 8432 is too wide. I could fit it on the baffle, but it would have interference with the engine mount. Time to see if I can squeeze a firewall mount on the left side.
 
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Rv7 angle valve

Here’s my 9row oil cooler on a -7 with angle valve. Don’t know the part number on the cooler but can get it for you next time I’m at the airport. Oil temps run around 190 degrees. If you go this route be sure to beef up the baffle.
 

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-7 Oil Cooler

The oil cooler on the above engine installation is an aero-classic #8001689 which is a replacement for the SW8432R.
 
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