Question for the Piston Experts Best HIGH compression piston

[1bolt]

Okay simple question, which hyperutectic offering provides the closest to zero deck (or above zero) before any machining is done. with the least amount of dish. Either 4.2 or 4.0 rods.

Basically which offering out there would be the worst piston to use for most people, and the best to use if you were building for E85 high CR, and very tight quench... A flat top or slightly domed piston even would be ideal. Something that isn't technically domed, but would end up above deck height by say .020 or less when coupled with 4.0 rods.

I figure I would spend all night researching this question if I didn't ask here, I'm betting some of you have already done the footwork.

[Cheromaniac]

I think the KB945's (11.4cc dish) on http://www.kb-silvolite.com/forged.php? ... s&P_id=542 may be what you're looking for. They're forged though, not hypereutectic, and go with the 4.0 rods in a stroker. If you shave 0.020" off the block and use the Mopar/Victor head gasket, quench will come in at 0.050" and the CR will be about 10.6:1. There may be an issue with piston-to-valve clearance depending on which cam you use.

[1bolt]

guess I was hoping there was something out there that was close to zero deck with the right rods, on hindsight I should have remembered that the whole KB stroker piston was about all that.

[Flash]

Any body now what the octane rating is, for E85 ? How much compression can you get a way with, with E85.


Flash

[John]

E85 runs about 105 octane, 12-13 :1 compression ratio is sweet on this fuel. It is hostile to some existing fuel tanks, lines etc.
Heres a good read on E85 http://members.tccoa.com/392bird/e85.htm
John

[1bolt]

Another factoid on E85 is that it has a similar charge cooling effect as with alcohol fuel dragsters (though not to the same degree). So it's not just the high octane that makes it resistant to detonation.

What started me thinking was the possibility of using 4.0 rods AND pistons on a stroker and machining off some of the crown to achieve a Dome or flat top piston.... Unfortunately with something like 9 or 10mm of the crown sticking up above the deck with the added stroke and only about 5mm of piston crown before the first ring, it's not even close to possible.

So in a moment of not thinking I figured I'd ask and see if there was any piston out there (besides expensive forged or custom jobs) that get near zero deck clearance.

[Flash]

E85 runs about 105 octane, 12-13 :1 compression ratio is sweet on this fuel. It is hostile to some existing fuel tanks, lines etc.
Heres a good read on E85 http://members.tccoa.com/392bird/e85.htm
John

Wow John, Another grate read!!!!!! Not to technical but lot of grate info
I especially like this statement: "The 105 Octane of E85 is very nice, but with the added cooling effect it makes it perform more like 115 Octane Racing Gas. There are guys running 16-1 compression ratio NA with E85, and NO pre-igniton."

WOW i thought straight ethanol would only support 12:1

Hmmm so, stock piston, 258 crank 4.0L rods and and shave ........remove top compression ring and shave top of piston to fit . I'm kidding here but there is some merit to it..........

Which is kinda were 1bolts mind is at. and has me thing on it as well!!!!!!!! Unfortunately its still 150+ miles in any direction to fine E-85 in my area but......... it getting closer to me

This was also intersting intervew with Jay lenno and Gale Banks
http://www.jaylenosgarage.com/video/vid ... vid=190247

Flash

[John]

I thought it worth reading, and yes it responds well to the increase in compression. 16.1, I think could be tough to work with considering our head design.
John

[Flash]

I thought it worth reading, and yes it responds well to the increase in compression. 16.1, I think could be tough to work with considering our head design.
John

Yeah 16:1 is getting close to diesel compression and i don't thing it would hold up at the compression.

My joke about shaving the piston down past the first ring...........well i was close.
To get "0" deck with a 258 crank w/ stock piston and rods would require the top of the piston to be shave .221 down........
.250" is 1/4 of a inch, for comparison

Flash

[John]

You are looking at custom pistons, price for 6 hypereutectic pistons, floating pins, cost to machine.... vs custom piston. Spec it to stand proud of the deck, thick flat top and then custom machine for valve clearance. Polish them well and have the tops coated. The head can be shaved over .2, I wouldn't. Careful cam selection is a must. Move valves closer together and enlarge them ever so slightly. Polish combustion chamber to 80 grit finish. 26# fuel injectors
John

[Flash]

You are looking at custom pistons, price for 6 hypereutectic pistons, floating pins, cost to machine.... vs custom piston. Spec it to stand proud of the deck, thick flat top and then custom machine for valve clearance. Polish them well and have the tops coated. The head can be shaved over .2, I wouldn't. Careful cam selection is a must. Move valves closer together and enlarge them ever so slightly. Polish combustion chamber to 80 grit finish. 26# fuel injectors
John

sound fun!!!!!!
BUT, way beyond by pocket book

It would be vary interesting to see what kind of mpg could be had from a 12.5:1 E85 compared to a 9.5:1 premium

With similar type cams........say the Crane cam or comp 231.
The E85 motor would make a lot more torque down low due to the compression ratio.

If you could lower the RPM and build boat load of torque..............were the the 9.5:1 had to rev the eng around double the
RPM to go get the same power............which would get the better mpg...........It just might even the table.

In all reality it would require two different cam to make the goal of X amount of HP with mpg in mind.
Say you were to set the HP rating at a some what of a difficult level of say.....300Hp
Nether one would get vary good mpg but i bet they would be vary close to each other with more power out of the E85
With a complete package such as axle gear ratio that is optimized for both setup in same kind and weight vehicle..............................
Another pluss, even tho 12.5:1 compression is vary high, with it using 85% Ethanol, the motor would run cooler then the 9.5:1 premo would.
The reason i say this is that when i was racing every weekend, my buddy had a 350 camaro with 12.5:1 eng running on Alcohol.
He could start his car drive it to the staging lane and let it idle for 10 minutes without having to even turn on his water pump.
My 9.4:1 chry small block would have the water pump and both electric fan on to keep it cool...............

No one has build a street eng around the E85 concept( probably mostly because of availability!!!!) but sounds like Mr Banks is on it

[John]

So back to reality of a street engine on E85. KB945's Shave the head .010, Deck the block to the chicken factor (valve clearance) and use .043 gasket. Look at Cliffords cams for one to keep a high DCR. Still think you will be looking for larger injectors. Pray the one E85 station within driving distance doesn't close.
John

[1bolt]

Imagineering the 4.0 pistons was what got me asking here, it's not even close to possible, but it was worth thinking about. The next logical CHEAP junk yard style thing to do is use the old 4.2 rods and 4.0 pistons. Which has been in my E85 plan since we were talking about this on NAXJA a couple years back. Not enlarging the dish will get decent static compression, and running a small turbo will provide the rest... The good part about this aproche is you can still run 93 octane pump unleaded, just turn the boost down with an adjustable BOV.

To solve the E85 supply issue in my neck of the Virginia woods, I might go full moonshine... As in building a still and fermenting it from high starch solids, and denaturing it with gasoline.

I've read that you can produce E85 for as little as a buck a gallon buying corn feedstock. Stills are not that hard to set up (if hill billys were doing it in the 30's...) and there's a lot that modern technology can bring to the table.

Its WAY better than Biodiesel because you just need starch (corn, potatoes, even houshold garbage possibly) you don't have to go to McDonalds and beg them for their waste french fry oil.

[Flash]

Imagineering the 4.0 pistons was what got me asking here, it's not even close to possible, but it was worth thinking about. The next logical CHEAP junk yard style thing to do is use the old 4.2 rods and 4.0 pistons. Which has been in my E85 plan since we were talking about this on NAXJA a couple years back. Not enlarging the dish will get decent static compression, and running a small turbo will provide the rest... The good part about this aproche is you can still run 93 octane pump unleaded, just turn the boost down with an adjustable BOV.

To solve the E85 supply issue in my neck of the Virginia woods, I might go full moonshine... As in building a still and fermenting it from high starch solids, and denaturing it with gasoline.

I've read that you can produce E85 for as little as a buck a gallon buying corn feedstock. Stills are not that hard to set up (if hill billys were doing it in the 30's...) and there's a lot that modern technology can bring to the table.

Its WAY better than Biodiesel because you just need starch (corn, potatoes, even houshold garbage possibly) you don't have to go to McDonalds and beg them for their waste french fry oil.

I like this idea a lot!
It would be cool if the waste gate was Power width modulated(would require some kind of computer for this way tho )so that you could set it for E-85(high boost) or 91/93 (minor boost.)
Therese's a lot of work ahead of yeah But the concept is Rock solid

Flash

[Wrambler]

Not wanting to beat a dead thread, but isn't there a chevy 250 6cyl piston that'll put the compression around 12-1?