Are all current CIS/Injector rubber rebuild seals alcohol friendly ?

[antares]

...Has anyone had any issues when it comes to currently available CIS injector O-rings, Fuel Distributor rings/ seals etc … and/or any other seal that would be coming in contact with current corn-a-hol fuels ? … The engine I am working on is getting a CIS rebuild and planning to use the Porsche factory dealer supplied injector and insert O-rings I bought a couple years ago … also rebuilt the fuel distributor about 10 years ago and put it on the shelf and have not used it as well … but got to thinking perhaps the seals and O-rings I used on the fuel distributor and these current injector seals may not be vitron type ethanol friendly seals and may just possibly be pre-ethanol old shelf stock and if so that would be a real obvious problem …

So is there anyway to determine if the factory ones I received are good to go for alcohol use and should I replaced the new small O-rings I installed on each fuel line coming out of the fuel distributor …. If so where should I be looking for alcohol friendly seals & rings ?
- dave

[Bob Kontak]

I am not schooled in this area.

However, to get some activity going to get you an answer I think you are simply working it too hard based on my wee bit of exposure. All will be fine.

[OldSpool87]

I applaud your thoroughness and the experts will likely shed light. If you can’t get 100% clarity (one rarely does), use what you got. I agree with Bob on this and coffee lids.

[Steve@Rennsport]

Dave,

You REALLY want to use Viton O-rings as those are only ethanol-resistant ones.

[antares]

… well Steve you got me there but I stated Vitron off the top of my head while typing … but that made my point non the less … and it is a real threat if these seals and rings are not compliant and that can go for the seals inside your 20 year old fuel pump or an NOS fuel pump as well … It is striking the old car hobby crowd hard these days … I rebuilt the fuel pump, sender unit, Carter, fuel filter etc on my 57 Buick for the same reason and the same science holds for my old 911 as well and since now that I am doing my CIS I guess an available compliant parts safari is no doubt on the horizon … If you are relying on NOS and or seals and o-rings that are not specifically coded for use with ethanol then the risk is real and literally having a " melt down " in one or many of your components sooner then later is as well …. So no Bob unfortunately things will not be just fine by just assuming that the seals you are purchasing today are actually compliant certified seals ….

So as per the original post if anyone knows for sure where one can obtain ethanol compliant o-rings and seals for the CIS please sound off or I suppose one can at least mic out the o-rings and out source for those - dave

[boyt911sc]

Originally Posted by antares

… well Steve you got me there but I stated Vitron off the top of my head while typing … but that made my point non the less … and it is a real threat if these seals and rings are not compliant and that can go for the seals inside your 20 year old fuel pump or an NOS fuel pump as well … It is striking the old car hobby crowd hard these days … I rebuilt the fuel pump, sender unit, Carter, fuel filter etc on my 57 Buick for the same reason and the same science holds for my old 911 as well and since now that I am doing my CIS I guess an available compliant parts safari is no doubt on the horizon … If you are relying on NOS and or seals and o-rings that are not specifically coded for use with ethanol then the risk is real and literally having a " melt down " in one or many of your components sooner then later is as well …. So no Bob unfortunately things will not be just fine by just assuming that the seals you are purchasing today are actually compliant c!ertified seals ….

So as per the original post if anyone knows for sure where one can obtain ethanol compliant o-rings and seals for the CIS please sound off or I suppose one can at least mic out the o-rings and out source for those - dave

David,

You are overthinking this simple procedure. If you installed the o-rings from an old Porsche rebuild kit, you had Viton o-rings. It would survive gasoline for many years and so with alcohol. The chemical resistivity of Viton to gasoline and alcohol is good. So stop worrying and enjoy the car. That is the least of your worry.

Tony

[antares]

… Tony are u assuming the o-rings sourced from Porsche some 16 years ago were then and still are vitron as I have a couple packs of new 30 year old p-car o-rings I bought back in the 80's on the shelf and they look taste and feel just like the ones I got from Porsche this past summer and I am pretty sure the 80's pack is not ethanol rated you think nor were the fuel distributor seals I installed back in 2001 as well … My Buick needed it's components as mentioned replaced and I rebuilt all of that back around 2006 and those seals did not like corn-a-hol and melted … what a mess … so call me dangerous for thinking but I don't want to have to mop up the same mess again with the p-car

[boyt911sc]

Originally Posted by antares

… Tony are u assuming the o-rings sourced from Porsche some 16 years ago were then and still are vitron as I have a couple packs of new 30 year old p-car o-rings I bought back in the 80's on the shelf and they look taste and feel just like the ones I got from Porsche this past summer and I am pretty sure the 80's pack is not ethanol rated you think nor were the fuel distributor seals I installed back in 2001 as well … My Buick needed it's components as mentioned replaced and I rebuilt all of that back around 2006 and those seals did not like corn-a-hol and melted … what a mess … so call me dangerous for thinking but I don't want to have to mop up the same mess again with the p-car

Antares,

Like I said earlier, Viton (a flouro elastomer compound invented by Du Pont) is one of the best synthetic rubber you could find in the market that has good chemical resistivity against gasoline, alcohol, and gasohol. The concern about fuel hoses is different because they are not made of Viton.

If you believe that your old orings are not Viton, then don’t use it. Simple as that. You are being paranoid about this alcohol effect on viton. I got a B.S. ChE degree and worked for Du Pont before retiring.

Tony

[manbridge 74]

Throw one of your old o-rings into a jar of E85. Check yearly.

I’d be more concerned about the FD coming out of long term storage.

[antares]

Tony … always appreciate your input yet no one is being paranoid regarding Viton here … no one I know asked anything about Viton nor the effect of R-OH on Viton as you are extrapolating so please reread the upper posts … so to get back on track … simply ... the original intent of this post was to ask if the current supply of seals and o-rings are R-OH compatible ( I have a degree in chemistry too as I am sure many do ) and no I do not have the time though it would be interesting to soak the currently acquired seals and o-rings I recently received this past summer in corn-a-hol and see what happens before I put things back together… so let me put it another way in a nutshell regarding Viton I and it appears no one else can so far confirm if indeed the seals and o-rings that have been available for say the past 7 years or so are actually Viton or not from either Porsche or after market suppliers and if we can determine that we can put all this to bed … :') … regarding the FD the seals were rubber lubed and no fuel and in a sealed pouch so not too concerned about it's functionality but rather the seals and rings installed as being compatible ….

O.K. so if anyone has installed the currently supplied CIS component seals and o-rings within the past couple of years I would like to know if you have experienced any problems … in the meantime I will see what compliance if any the batch I have on hand or what has been available is or not …. thanks for everyones input - dave

[Tippy]

Antares, I got your question from the beginning. You asked it several times too. You asked it clearly to me. Not sure why some are missing the boat?

Sorry though, don't know the answer.

[boyt911sc]

David,

You being a chemist would be the last person I would expect not to understand your predicament. If you are not certain that they are NOT Viton o-rings, do not use them. If you don’t have the time to solve your problem so are we.







I have been using Viton FKM for my rebuilds and been very satisfied with the results.

Tony

[Tippy]

"assuming the o-rings sourced from Porsche some 16 years ago were then and still are viton as I have a couple packs of new 30 year old p-car o-rings I bought back in the 80's on the shelf and they look taste and feel just like the ones I got from Porsche this past summer and I am pretty sure the 80's pack is not ethanol rated you think nor were the fuel distributor seals I installed back in 2001 as well"

[pmax]

I'm no chemist but I do have interest and time for keyboard research.

Fluoro-elastomer (Viton) gets a C in this chart vs ethyl alcohol. How's that ?

https://www.sterlitech.com/oring-compatibility-chart

Another site concurs with a "Poor" (20-40% swell) rating for Viton FKM in your favorite beverage.

https://www.marcorubber.com/o-ring-chemical-compatibility-chart-5.htm

[boyt911sc]

Originally Posted by pmax

I'm no chemist but I do have interest and time for keyboard research.

Fluoro-elastomer (Viton) gets a C in this chart vs ethyl alcohol. How's that ?

https://www.sterlitech.com/oring-compatibility-chart

Another site concurs with a "Poor" (20-40% swell) rating for Viton FKM in your favorite beverage.

https://www.marcorubber.com/o-ring-chemical-compatibility-chart-5.htm

Sean,

The Chemical Resistance Tests were done using 100% concentration of each solvent. The ethanol in today's gasoline is about 10% and 90% gasoline. If you look closer under gasohol (mixture of gasoline and ethanol), there is no available data or insufficient information as of today.

The chart shows Viton has a poor chemical resistance to 100% ethanol but no evidence to show at 10% level. The concentration of ethanol you are comparing is 10:1 or 10 times more than current ethanol level in commercial fuel.

If you drink 100% alcohol you will probably not survive but at low concentration in your drink will make you enjoy life or be more depressed.

Tony

[antares]

… thanks Cory & Tony for that … So for kicks I have put some of these old seals and rings into a beaker titrated low at 10% molar concentration of R-H + R-OH to see what happens in about 3 months because at this low micelle level of solutes it will mimic actual in vivo conditions ... this should then give us an idea ... but in the meantime Tony I have to put this system back together & no if I do not know if the seals and rings I have on hand are not compatible rest assured I will not use them …

So Tony … you say you are using your certified fluorocarbon seals and o-rings and you report good lasting results … so then please share your source and I will pick some up :') - uncle dave