Will it dissolve? Two month anti-vibration pad ethanol test results

In our fuel system, the pump anti-vibration pad (PN 126807) was considered a potential weak point with modern ethanol containing gasoline (along historically with the actual holder PN 170511… in park that was well established to dissolve when exposed to ethanol).

While today a revised ethanol-resistant 170511 is available, it was unclear if the vibration pad was similarly updated or if it was still susceptible to degradation.

A cheap Viton flange gasket was historically the go to alternative (which not only is resistant to ethanol, but much cheaper to boot; photos 1 and 2 below). Viton is a well-known and well established gasket material that is resistant to many solvents.

Here I tested both the current 126807 (labeled FMSD 126807) and the usual viton gasket (as a control) by leaving them in a jar of 70% ethanol.

Long story short, the current labeled FMSD 126807 is resistant to ethanol degradation, showing no breakdown/degradation/pilling/etc after being left in ethanol for over 6 weeks.

On the left (3rd photo), you can see the Viton is essentially unchanged. On the right you can see a cut up FMSD 126807 is likewise intact; no material is coming off on the paper towel, nor is there any degradation along the cut edges (aka it’s not just a coating, but the material itself remains intact).

In summary, I would be perfectly satisfied using either in a fuel system refresh and plan to for first m my 456m then 512TR.

For those curious, my full 456m fuel system refresh checklist is as follows (yes, this is extreme overkill, but I am refreshing a now 25-year-old system):

[x] gasket x2 (126835)
[x] Al/metal faceplate x2 (from GTCP)
[x] fuel pumps x2 (173891)
[x] fuel filters 186922 x2
[x] upgraded/updated fuel sender (RS154556 from Ricambi or directly from the UK supplier)
[x] vibration pad (FMSD 126807)
[x] Pump Support: Fabio FE.04.009 x2 vs revised PN 170511 x2
[x] Evan valves (PN 162412 x3?)
[x] evaporation canister (174782)​

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Ps pardon typos, posting from my phone since it’s easier to add photos…

 

I would advise against nickel and dime'ing there, particularly as its only $10 for the Viton substitute pad. The vibration pad helps mitigate high frequency driveline vibrations from causing issues with pump and fuel flow in that setting to limit bubbles / frothing / etc (I would assume). Personally, I think its most important for the 456GTA given their known driveline vibrations and rather delicate fuel systems (in the case of early 456Ms in particular).
For a 512TR though, please refer to my post there as the listed PN here are for the 456 (and to some extent 550). https://www.ferrarichat.com/forum/threads/512tr-fuel-system-redux-to-account-for-etoh-gasoline.703358/