Possible Vapor lock?

SilverLightAviation

Enough people have asked me for this that I decided to just post it.  This is based on the ASTM D323 standards, but my approach uses low cost and easy to get parts and methods. I have found it to be quite accurate, but all you are really looking for is to know if you have summer fuel or winter fuel. With Summer fuel having an RVP of about 8 and winter fuel 12-13 it's easy to tell the difference. If you construct this tester, try it on Avgas and you should get about 6-7 PSI.  The precooling is done with ice, and the heating is done with hot water, so this is very safe.  Just remember you are working with gasoline and take normal precautions. Also, use this at your own risk. Also, early in this string Bill Hertzel posted a very nice spreadsheet showing the safe altitude/temperature combinations for various fuel vapor pressures. 

For someone to do  the test and does not want to build the tooling it is available from very pricy to the DIY stuff.  Here is a nice alternative, you can find similar online.

https://www.drumpreserve.com/product-p/dptester.htm

Cheers

Note: RVP of summer fuel with 10% ethanol usually is allowed 1 point higher RVP, so up to 14/15 in summer fuels.  The issue is when the supplier sells this fuel after the cut off date, normally May 15th.  The combination of hot weather and high RVP is the most likely cause of vapor lock.  There is now a requirement under ASTM F37 aircraft standards for the OEM to test worst case fuel with hot environments.  The test is outlined in the latest standards. 

RW

I could not find a low cost test vessel like the one you posted back when I built mine.  I think for $120.00 that’s a great option, and the built-in thermometer is a great feature. Interesting that they state that’s it’s for non-flammable fluids, while their primary product is a fuel storage system. I guess they have to do that for liability. 

Jeff

Check for used ones, most are made in China now.  OTC, a automotive tool supplier, used to make one that Snap0n tools had as well as it was sold via Audi and VW for RVP testing.  They are discontinued but if you can still find one they were very inexpensive.  only full size shop ones are online that I can see right now.  Problem is the cost. 

here is a full on set up from China, but a bit rich for me. 

https://chinainstrument.en.made-in-china.com/product/INRxwtKOLkhV/China-ASTM-D323-Rvp-Reid-Vapor-Pressure-Tester-for-Fuels.html

here is just for fun, you can see an operations video from one of the expensive suppliers

https://www.youtube.com/watch?v=N7Jzxk5FQNs

Cheers