1/2 in Female NPT fittings on oil cooler, could it work?

[billy911]

I've come across a used oil cooler that's 14" long by 7" wide with 1/2 inch female NPT fittings with 5/8" tubing. It's pretty cheap looking, but I'm sure it would do better than the trombone "cooler" in my 78SC. Are there adapter's I can use on this to get it to attach to my existing lines? If so, does anyone know the specs on the threads and size of the original lines? BTW it's only $25, so I guess It wouldn't hurt to try for that price. Thanks for any info!

[Jim Smolka]

I would not recommend using a cooler with 1/2" NPT threads. The lines on a stock cooler are 30mm. Most folks agree that 3/4" inch is the smallest that should be used. 1" NPT is better.

Reading Bruce Anderson's book, he states that he has seen oil pump failure due to too restrictive oil line an oil coolers.

[Early_S_Man]

If I understand your description, the cooler is similar to an A/C condensor, or auto trans cooler, in that it uses a serpentine single tube of approx. 1/2" I.D. and probably 8 to 12 feet long. That is a REALLY BAD IDEA, considering that the factory front cooler lines are 22 mm ... about 7/8" diameter (exactly the same I.D. as AN-16 lines) and the the 'cooler' alternatives to the 'trombone' actually present less restriction than the uniform diameter of the approx. four-foot long loop of the trombone! A good cooler like the factory models present a surface area of 1.5-3 square inches, and a total flow path length of 2- 2.5 feet ... the additional surface are of the oil path slows down the oil flow velocty through the cooler so as to maximize heat transfer.

The end result of your proposed cooler would be to put a considerable additional load on the scavenge pump, and that is not such a good idea, as pointed out above!

[J P Stein]

-12 line is the minimum recomended line size.......-12 is 12mm ID (.4724"). You can do the math for-16. I found -16 goodies harder to come by ($$$$).The -12 stuff does make life harder for the oil pump.....sumthin' else to worry about (sigh).

I used -12 and the only thing I have learned thus far is:
A full flow of cold oil cannot be pushed thru my aux. system. The oil pump is a robust little devil and more than capable of blowing the guts out of my aux. cooler. This was due to an error on my part.....which only proves that nothing is idiot proof.
The good news here is that Fluidyne (oil coolers)stands behind their product, saying that there is no way that the cooler should have failed. They sent me a new one, FOC.

Speaking of "cheap looking" coolers, that's what I thought about a Mocal unit I had my grubbies on......it went back to where it came from.

[billy911]

Thanks for that info guys!! I never thought about the additional pressure and stress on the pump, that's kinda scary. Guess I'm gonna have to save up for the factory cooler ...