Backcountry Pilot • Toluene VS Buna N O-Rings?

Toluene VS Buna N O-Rings?

Nothing happens without it. Discuss fuel locations, quality, alternatives, and anything else related to this critical resource.
9 postsPage 1 of 1

Toluene VS Buna N O-Rings?

Toluene is used in auto fuel for an octane booster but is not compatible with Buna N O-rings.
Where I get my ethanal free fuel the distributor says that it is 50ppm Toluene.
I haven't researched it yet.....but what's the deal?
A while back I had an o-ring swell up in my fuel selector valve, it restricted flow to about 12gph from one tank. Was it from the Toluene?
I test my fuel regularly and know I haven't run ethanol through it.
Does Toluene fit in with the auto fuel STC?
Terry offline
User avatar
Posts: 1121
Joined: Sat Nov 10, 2007 9:11 pm
Location: Willamette Valley
FindMeSpot URL: http://share.findmespot.com/shared/face ... 4GzPHI6t1d

Re: Toluene VS Buna N O-Rings?

Not airplane related, but I recently had buna-n o-ring problems in my powerstroke because the ultra low sulphur fuel would make them shrink/harden. I swapped them for viton o-rings and haven't had any issues.
ajfriz offline
Posts: 97
Joined: Fri Nov 26, 2010 6:25 pm
Location: Logan
1940 BC-65 with some mods.

Re: Toluene VS Buna N O-Rings?

Sure glad you posted. Just think of the bad rap ethanol has gotten and probably as much or more the gasoline was the problem. I know of a fuel selector that has had E10 going through for almost 5 years and it doesn't leak. That o-ring is way older than 5 years also.
Last edited by 180Marty on Wed Nov 09, 2011 4:26 pm, edited 1 time in total.
180Marty offline
Posts: 784
Joined: Mon Jan 02, 2006 11:59 am
Location: Paullina IA

Re: Toluene VS Buna N O-Rings?

Image
180Marty offline
Posts: 784
Joined: Mon Jan 02, 2006 11:59 am
Location: Paullina IA

Re: Toluene VS Buna N O-Rings?

It sounds like toluene is also in 100ll, maybe it's not a big deal?

Here is a compatibility guide.
http://catalog.gpi.net/Asset/Chemical-Compatibility-Ver-6.pdf
Terry offline
User avatar
Posts: 1121
Joined: Sat Nov 10, 2007 9:11 pm
Location: Willamette Valley
FindMeSpot URL: http://share.findmespot.com/shared/face ... 4GzPHI6t1d

Re: Toluene VS Buna N O-Rings?

Viton (a perfluorelastomer) is fine in toluene. Kalrez is actually better, especially at elevated temps, but the cost does not really pencil out.

McMaster.com

I ran into the problem when folks were replacing the primer with the wrong o-rings- and made the primer unusable.
lesuther offline
Posts: 748
Joined: Fri Sep 24, 2010 1:26 pm
Location: CO

Re: Toluene VS Buna N O-Rings?

We use Viton 75 O-Rings in our Gascolator's specifically because of this exact problem. Viton 75 is impervious to all known fuels including straight alcohol, diesel, jet A, etc...

Brian.
Brian-StevesAircraft offline
User avatar
Posts: 315
Joined: Tue Dec 13, 2005 1:13 pm
Location: Beagle (White City) Oregon
Pavement scares me..........

Dad's SPOT page

Re: Toluene VS Buna N O-Rings?

We use Viton 75 O-Rings in our Gascolator's specifically because of this exact problem. Viton 75 is impervious to all known fuels including straight alcohol, diesel, jet A, etc...

You wonder why they even make the other kinds that aren't impervious to everything.
180Marty offline
Posts: 784
Joined: Mon Jan 02, 2006 11:59 am
Location: Paullina IA

Re: Toluene VS Buna N O-Rings?

http://www.marcorubber.com/material_chart.htm

This is a materials chart showing basic compatibility with fluids for the different compounds of O-Rings. Viton 75 is not very good for Steam or standard automotive type brake fluids.

If you really want to do your research you can go here http://www.marcorubber.com/compatibility.htm and look up the particular fluid in the drop down list and see what rating the O-Ring is at for that fluid. On this list Viton A is listed as a #2 (scale 1-4) at a 10 to 20% swell for Toluene. Butyle is rated 4 - not recomemded.

Brian.
Brian-StevesAircraft offline
User avatar
Posts: 315
Joined: Tue Dec 13, 2005 1:13 pm
Location: Beagle (White City) Oregon
Pavement scares me..........

Dad's SPOT page

DISPLAY OPTIONS

9 postsPage 1 of 1

Who is online

Users browsing this forum: No registered users and 0 guests