Engine wear and E85

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or rather lack of.

Not sure if posted before.

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http://www.camaros.net/forums/showthread.php?t=143372
 
Originally Posted By: PZR2874
Did he run in that hard where it's all "worn" or is it a load and he was taking a pic at the machine shop before the honing?


description in the quoted forum:

Quote:
Engine is SBC 4.145" bore x 3.800" stroke with SRP forged flat top pistons. This is a solid roller cammed engine that is 11.4:1 compression and has been run almost exclusively on E85 since spring 2007. It did have 6 months run time on gasoline before the switch. I was surprised at how clean everything is -- I have NEVER seen pistons this clean after 2 years of use.

There was no ridge at the top of the cylinders, and no scoring or other signs of a lubrication problem in the bores. Engine has 250+ quarter mile passes on it and 15,000 street miles. I cruise on the freeway at 3400-3600 RPM and do NOT take it easy on this thing.
 
Cross hatching is the marks left from cylinder honing.Its how the rings break in and make a seal.
 
Correct, but I didn't realize he was using gapless rings... I was looking for the hatching and agreed with everyone else. Still, very clean cylinders.
 
How's the fuel consumption on E85? Just bought a new Poulan 4 cycle snowblower and the manual (I read them) says the warranty is void if more than 10% alcohol is used.
 
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Very nice. I agree those are some clean pistons.

I guess the camera lacked the resolution to show us the cross hatch. otherwise there should be a deep ridge.
 
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Wow. I feel a lot better using E85 in my 2013 Silverado frequently. Yeah, mpg is not like with gas, but the price differential still makes it more cost effective per mile to use. And you can tell the difference in pep via the seat dyno. E85 definitely puts regular gas to shame on get up and go.
 
fine if like being locked to only one fuel. get in the middle of nowhere and only reg gasoline? so what do you with 89 octane in a 11 to 1 C.R. time for MMO.
 
The link to the thread the OP referenced, the guy with the 11:1 CR started out the engine on Premium gasoline for 6 months before going to E85. It would have to be pretty "middle of nowhere" to not be able to get premium. I lived in Delta Junction Alaska for several years. More remote than most folks on this forum will see, and we had Premium available. Bit of a stretch that he would be locked into one fuel.

That is why I like my Flex Fuel Silverado. When combined with a Diablo tuner, I can set the high performance 93 octane tune and use two different fuels, premium and E85. If either was not available, just switch to the 87/89 octane program and can use regular, E10, or E85.
 
Originally Posted By: SteveSRT8
Very nice. I agree those are some clean pistons.

I guess the camera lacked the resolution to show us the cross hatch. otherwise there should be a deep ridge.


About mid bore on the RHS piston, you can see a "holograph" for want of a better word where the diamon cross hatch is giving a sort of fresnel reflector...but the vertical lines far outweigh that image.

Given that the engine is reputedly turnign 3,600 RPM on the highway, that's a pretty low MEP, which means that the time that the rings are at TDC/BDC, they have lower pressure behind them than one turning (say) 1500RPM and needing twice the torque/MEP per revolution...less impetus for a ridge to be foremed, and less "dwell" with the piston transitioning from hydrodynamic to boundary.
 
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