WMO/diesel blend eating seals in PVC ball valve - Diesel Forum

arthurgoboom · 10-22-2008, 06:41 PM

I am using PVC ball valves from Menards (KBI brand) on my mixing/filtering rig, and apparently the diesel/WMO is degrading the stem seal in the valves. Thus the valve that goes to my filter array is seeping fuel when the pump is on. Line pressure is 15 psi. This problem only first presented itself today when I started using a 1-micron filter, thus the flow resistance (and pressure) is higher.

I have seen other setups that said PVC is just fine to use. Is anyone else having this problem? If there are others using PVC ball valves, what is the source/brand of your valves?

Thanks!

axjy · 01-21-2009, 09:03 PM

yes , me too

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phatb · 01-22-2009, 01:17 PM

PVC is NOT a good choice for longevity, it degrades over time, pipes will crack, and you are already experiencing the valve failure.

If you can afford it, switch to black pipe and brass full port ball valves.

Just offering my 2¢, take it for what its worth....

yaric008 · 01-22-2009, 01:30 PM

You need valves with teflon seals. Preferably brass or bronze valves with teflon seals. I've had PVC valves just crack right down the middle and start leaking everywhere. Luckily I was around to stop it before it made a gigantic mess.

Racer-X · 01-22-2009, 07:58 PM

Has anyone ever asked the question WHY the PVC degrades?
What does WMO put out the tail pipe?
What's it doing to the seals in the fuel system? Injectors?
Has anyone ran this exclusively for extended periods? (ie. 200,000 miles)

Just thought I should ask,because if it was good to do, everyone would be burning WMO.

phatb · 01-23-2009, 01:18 AM

Everyone is on this craze to not put solvents in your fuel tank, well fact be known, diesel fuel is also a solvent, I know of several folks using ULSD in their parts washer because of its excellent performance and its cheaper than regular parts washer solvent (which is just mineral spirits with a rust inhibitor).
Anyway, with that said, on to my point. Solvents dry out the PVC making it brittle and prone to cracking over time, that is why you can get away with it for a period of time, and then all of a sudden you will start having failure after failure. This is also another reason why you should never buy or make a BioDiesel processor that is piped with PVC, it's cheap and going to fail you when you least expect it.

ReefBlue · 01-26-2009, 08:32 AM

Quote:

Originally Posted by Racer-X

Has anyone ever asked the question WHY the PVC degrades?
What does WMO put out the tail pipe?
What's it doing to the seals in the fuel system? Injectors?
Has anyone ran this exclusively for extended periods? (ie. 200,000 miles)

Just thought I should ask,because if it was good to do, everyone would be burning WMO.

Thousands of miles over the last year. There is a lot of experience with this stuff here.

Check out the thread 'how many miles on wmo', people are doing 50k miles without a problem.

Not everyone can do it because if you require ULSD in your engine and you run this stuff, it will damage it.

I don't think it is because people perceive a problem, I just think the ability to use WMO isn't widely known.

Also, not a lot of people can get WMO in bulk. I get it from generator oil changes at work, if caterpillar wouldn't leave me the oil at my request, I would only get the oil change oil from my truck and unable to really run this stuff beyond what I could scrounge.

arthurgoboom · 03-19-2009, 10:32 PM

Ok kids, it came to my attention that Harbor Freight has their brass WOG ball valves on sale. $3.99 for 1/2" NPT, brass body stainless steel ball with teflon seal. Now's the time to get them...