E85 = accelerated piston and ring wear? 1

[Mechaniac]

This was posted on a forum I frequent:
"The company I work for makes the low friction coating for the piston skirts of all GM and Ford pistons. And no, there is no teflon in the formulation. I have been working with the piston manufacturers on a new coating formulation when one of the lead engineers asked me if I have used E85 in my new Tahoe. I said no and he said good, don't. When questioned he explained that they still don't have the capability of making the engines last when on a diet of E85. He said GM has decided it is cheaper to replace engines under warranty that use E85 rather than engineering them to actually use the stuff without damage. He said this will continue to be GM's policy till E85 becomes more available and changes the cost/risk ratio. " B.T.

Anybody able to comment? Yea or nay? E85 usage with current engine designs in general. I've converted my Chevrolet Truck to E85 and have been using it daily since last May. I haven't seen any issues as of yet. It does seem that some people in the oil and gasoline industry have a agenda strongly against E85, and much of it seems rubbish.

Thanks,
Vernon

 

[ivymike]

so somebody at Dow says that somebody from Federal Mogul told him that he heard GM's policy was such-and-such? Sounds pretty reliable.

E85 is more corrosive than E10.. but how long does liquid fuel stay in the 'hood of the piston crown? Even a chrome ring coating would probably do just fine... how long does the cylinder wall stay wet with fuel? I dunno. I've seen wierder things kill a P/R/L before. Upstream corrosion could conceivably generate enough debris to shorten the life of the top ring flanks and top groove flanks (assuming the intake tract stays wet w/fuel long enough to cause damage).

 

[drwebb]

GM is slapping "Flex Fuel" on as many trunk lids as they can to promote a greener, higher tech brand image. If they don't have confidence in them then they're knowingly setting themselves up for a fall if E85 DOES become more widely available in 5-7 years. The story sounds cryptic to me.

 

[KyleReasbeck]

Just taking a stab here...but any damage severe enough from fuel would have to be:
a) washing of the fuel down the cylinders...therefore wiping rings which i would think would also....

b) put a high concentration of fuel in the oil, shortening bearing life

c)alot of detonation

As far as alcohol, there is enough knowledge out there to hae the timing and fuel quantities at the right values to ensure full (well as good as norm) combustion. I have a hard time that GM would miss the boat and throw enough excess fuel into the cylinder to cause a and b and they would also have the proper timing setting and fuel volume setting to work with E85.

 

[reidh]

I don't think that any of these are very likely.

a&b) Hopefully there isn't that great of a quantity of fuel at the cylinder walls, it certainly isn't desirable in most applications.
c) since the octane of ethanol is greater than that of standard gasoline, I would hope that detonation isn't an issue.

-Reidh

 

[KyleReasbeck]

Reidh,
I agree hopefully there's not that much fuel in the cylinder and that since the octane is higher detonation would not be an issue, but other than those two things how else could an engine be severely damaged due to piston and ring wear by a stand-alone fuel issue? I dont think there is any real problems, sounds like just a rumor, but if there is, i'd imagine it'd have to fall in the realm of one of those two items....

 

[patprimmer]

If fuel ends up in an engine after shut down, which it almost certainly will, some will condense on the cylinder walls and ring grove areas. This can absorb moisture and make a highly corrosive solution. It is not normally a problem with short duration shut downs, but can be a problem during extensive periods of non use.

Regards

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[drwebb]

SL and SM spec engine oils use the Ball Rust Test (ASTM D 6557) to gauge anti-corrosion performance. Don't know if field performance correlation is affected in engines running E85 but seems an obvious question for the GM engineers to have considered.

 

[Mechaniac]

Thanks for your thoughts, all is appreciated.

I was scanning through a maintainence schedule for a 2005 Ford F150 yesterday and noted that oil changes for any vehicles using E85 more than 50% of the time were on the shortest schedule.

I changed the oil in my truck a last week and it looked, felt, and smelled very good compared to when I used gasoline. It must have been one of the longest oil life periods the vehicles processor had ever produced. I was beginning to think it failed or been reset somehow. I use Shell Rotella Synthetic 5W-40, diesel spec oil.

So far I've noted only positive effects on the engine from E85 usage.

Vernon

 

[himwhotinkers]

why not use a friction reducer in the fuel ? There is a product called ca40 that is suppose to work in gas , alcohol and diesel . And no i am not promoting this but i have used it in diesel and automotive engines and there is something to it

 

[patprimmer]

I just cut this from their websit.

Combustion Enhancement
Unlike other additives, CA-40 is not a solvent. It is actually a combustion enhancer. Usually only about half of the hydrocarbons in fuel are burned in an internal combustion engine. Combustion enhancement is attained through further oxidation of the un-burnt hydrocarbons in the fuel.

To anyone who knows anything about this subject, this is absolute, unadulterated male bovine manure which seems to imply that the product is pure snake oil.

Extra wear in an ethanol fuelled engine if it in fact occurs will be due to the richer mixture washing down the bores, or from corrosion occurring mainly during extended periods of no operation. Upper cylinder lube in several forms, including castor oil, or 2 stroke oil for alcohol racing motors would help against both potential causes.

Petrol on it's own also is quite a poor lubricant.

Regards

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[dgallup]

What are the differences between unadulterated male bovine manure and the fatty extracts (eicosapentaenic acid, myristic acid, stearic acid, oleic acid, linoleic acid , arachidonic acid, etc.) of CLASS REPTILA ORDER SQUAMATA SUBORDER SERPENTES?

 

[RossABQ]

The real reason for the proliferation of FlexFuel'd vehicles is that the Mfr. gets a CAFE credit for doing almost nothing. Not saying they don't work, but...

 

[patprimmer]

dgallup

They certainly overlap. One is any form of lying and one is a useless product sold by extensive lying.

The inclusion of a very definite and elaborate lie in the sales pitch certainly indicates that the product may in fact be so useless that it cannot be sold on fact, nor even on moderate exaggeration.

Regards

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[sroberts2002]

I have just jointed this group and I see that I will be able to a learn and add to it. as for the E-85 issue I have been racing wil pure ethanol for many years and it is a fuel time issue also it the engine was built for it there should be no problems. the one thing I have done was taper the pitsons more to allow for extra expansion and Im sure GM with all it's racing knowlegde knows this.

 

[drwebb]

Racing experience is severe for high speed service but may not turn up problems with low speed origins. Would the fuel washdown mechanism that has been proposed be expected to surface in a racing application?

 

[patprimmer]

The fuel wash down mechanism is more likely to surface in racing due to use of rich mixture to obtain maximum power at the expense of economy, and because very rich mixture might be used to prevent detonation in high compression or high boost engines.

Also, car manufactures spend a lot of time optimising all aspects of fuel delivery, while racers only optimise power and response.



Regards

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