Another oil cooler question

[DanH]

Originally Posted by pecanflyboy

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.

[pecanflyboy]

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.

[Loren]

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.

[Loren]

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

[pecanflyboy]

Originally Posted by Loren

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

Thanks for that. I'll have to take a look. There is always a way, and I appreciate the pictures.