Methanol risky?

[Jason96SL2]

OK, my WI setup is a 60 psi pump feeding a MSD competition 50 lb/hr alchohol injector. I was going to do a methanol/water mixture until I heard rumors of destroying gaskets in the engine. Is this true? This car is my daily driver, so having to tear it down more often than I already do isn't an option. Should I do a 50/50 water/isopropanol or ethanol mixture instead? Will isopropanol destroy things too? Thanks.

[hotrod]

I don't think you have any problems with engine gaskets. Years ago with carburated systems there were issues with carburators that had composition cork gaskets, needle valve, and plastic foam floats in the float bowl, that broke down when exposed to alcohol, and some pre 1970's fuel hose would leak over time if exposed to alcohol fuels. All of those issues have generally been resolved completely with ethanol (due to its use in alcohol fuel blends) and to a lesser extent for methanol. The most likely issue today with methanol (and other alcohols) are seal materials used in the fuel system itself, and occasionally certain metals used in some fuel systems.

It depends a bit on the seal materials used in your pump/injectors etc.

Generally Methanol has some corrosion problems with certain metals in the fuel system. Aluminum (not anodized) and magnezium if I recall correctly are two of the metals that are most prone to corrosion in the presence of methanol. The so called Tern coating used in some fuel tanks also has problems with some alcohols. Ethanol is less agressive with metals and is prefered in comsumer fuel blends for that reason. ( that is one of the reason it is becoming popular as a fuel oxigenate)

The reaction of seal materials and alcohols differs widely. Each seal material behaves differently. You have two issues, permeability and degradation.

There are some seal materials that work well with each. If you can determine from the manufacture what materials were used for seals and gaskets in you system, than you can determine which alcohol is best for you. Common seal materials are Santoprene, viton, neoprean Buna-N etc.

I have seen some of this info scattered about in various places on the internet, but it might be nice if we had a sticky post here that listed the common seal materials and and their behavior with different alcohols.

Larry

[hotrod]

Here's a quick digest of some information I found with a quick search on Google.


Santoprene
http://www.tamparubber.com/gasksant.htm

Acetone ------------------- minor effect
water ----------------------- little or no effect
Ethanol -------------------- minor effect
Methanol------------------ little or no effect
Isopropal alcohol------- Not specified specifically but minor effect for alcohols

gasoline ------------------ severe effect not recommended
toluene ------------------- severe effect not recommended
xylene--------------------- severe effect not recommended




http://www.colonialengineering.com/downloads/OnlineCat/16CHEMIC.PDF

methanol ethanol acetone isopropal alcohol
teflon not specified recommended up to 350 deg F recommended
epdm recommended recommended up to 70 deg F recommended
viton not specified not rec not rec recommended
buna not rec recommended not rec lacks recommended
santoprene not specified not specified not specified lacks recommended



http://www.sentranllc.com/pdfs/tb_chem.pdf
methanol ethanol acetone isopropal alcohol
teflon A -- A --
nylon A A A A
epdm 000000000000000000000000 not specified 000000000000000000000000000
viton C A D A
buna 000000000000000000000000 not specified 000000000000000000000000000
santoprene -- -- -- --
neoprene A A C B
silicone -- B B C

A - Recommended, excellent resistance
B - Satisfactory, minor effect good resistance
C - Limied use, moderate effect fair resistance
D - Not recommended severe effects imminent


Larry

[Jason96SL2]

My ENTIRE engine is made of aluminum...even my pistons (forged aluminum). Kinda scary eh?

[hotrod]

The fact the engine is made of aluminum is not important. The issue with methanol and corrosion only applies to metal parts that are "wetted" by the fuel continously, ie the inside of injectors, fuel rails, fuel lines etc.

Larry

[AKWRX]

The fact the engine is made of aluminum is not important. The issue with methanol and corrosion only applies to metal parts that are "wetted" by the fuel continously, ie the inside of injectors, fuel rails, fuel lines etc. Larry

Agreed. Unless you are adding large quantities of methanol to the gas tank, none of the fuel system is exposed to any significant amounts of alcohol. When injecting, only the intake tract downstream of the nozzle sees any alcohol. Once in the combustion chamber it's chemical compostion changes under the heat of combustion to mostly water vapor, and the usual gas byproducts. Even alcohol "funny" cars running all methanol don't have any long term corrosion issues. However, that may be a bad example, since the service life of those engines isn't very long anyhow. Not sure what alcohol does to aluminum, but it probably just speeds up the normal coating of aluminum oxide that exposure to oxygen does to all uncoated aluminum.

[Warren_from_PINZ]

I want to add that methanol is very corrosive to copper and bronze as I found out one day when I found water on the outside of my carb. When I went to pull off the WI hose on the bronze/copper? nozzle, it fell off in my hand! The nozzle (vaccum advance input to carb, actually) was corroded so badly it just disintegrated. This took a couple of years but I hardly ever used methanol... just water 95% of the time.

I'd check your throttle butterflies to see what they're made of. In my experience they seem to be bronze a lot of the time.

I've read that ethanol doesn't have that problem but doesn't provide as much power as methanol. Here in New Zealand you're allowed to distill your own booze so I might consider using that as it would be ultra cheap.

[hotrod]

The difference in power from methanol and ethanol is mostly theoretical.
In tests run durning WWII on water injection for combat aircraft there were no significant differences between ethanol and methanol mixes. There were however major differences with isopropyl as it needs significantly different injection rates than ethanol and methanol. The difference was significant enough that when air crew used isopropyl (de-icing alcohol) in the ADI systems they blew engines because the system was calibrated for ethanol and methanol.

Methaol is more corrosive than ethanol as it is electrically conductive. It increases electrolytic corrosion caused by dissimilar metals that are constantly wetted by the injection fluid. It will generally have no effect on metals that are not in continous contact with the solution with the possible exception of Zinc and magnesium and maybe unanodized aluminum.

Larry

[Warren_from_PINZ]

Methaol is more corrosive than ethanol as it is electrically conductive. It increases electrolytic corrosion caused by dissimilar metals that are constantly wetted by the injection fluid. It will generally have no effect on metals that are not in continous contact with the solution with the possible exception of Zinc and magnesium and maybe unanodized aluminum.

Larry

Wow, I've never heard that before! Thinking about it now, the corroded brass I found was pressed into an aluminum carburettor so it may have been caused by electrolysis. I'm astounded that methanol is conductive though.....

[TurboGTi]

isn't methanol a fuel also..

i thought the injection of methanol has an added benifit as being a fuel, apart from its cooling properties.

[AKWRX]

isn't methanol a fuel also..
i thought the injection of methanol has an added benifit as being a fuel, apart from its cooling properties.

Methanol is not only a fuel, it also adds significant amounts of oxygen to the mix. While the additional oxygen is not nearly as much as NOS, it still must be taken into account when tuning. Being both a fuel, and adding oxygen, methanol alcohol significantly changes the stoich value of the mix. When injecting larger (>20%) quantities of methanol, the impact on trying to tune to target A/F ratios with a wideband oxygen sensor set to gasoline's 14.7 stoich value becomes more difficult.