Ok, to breathe new life into this..

I've been doing some serious thinking over the past few months, and after some dissection of an LE5 I obtained, I have new information to add.

lets start with the numbers everyone is familiar with:

OEM ecotecs:

LE5 Ecotec

bore = 88mm
compression height = 28mm
wrist pin diameter = 20mm
stroke = 98mm
rod length = 143.7386mm
rod ratio = 1.46:1
total bottom end height = 220.74mm


LSJ Ecotec

bore = 86mm
compression height = 30.86mm
wrist pin diameter = 23mm
stroke = 86mm
rod length = 145.5mm
rod ratio = 1.69:1
total bottom end height = 219.35mm


L61 Ecotec

bore = 86mm
compression height = 26.75mm
wrist pin diameter = 20mm
stroke = 94.6mm
rod length = 146.5mm
rod ratio = 1.54:1
total bottom end height = 220.55

Now, here are the revised hybrid options. Not a lot of movement is available, but with some custom parts you can build a pretty sweet ecotec engine without sacrificing too much displacement.

2.1 custom rod/ NA
Ingredients:
-LE5 block
-LSJ crank
-LE5 pistons
-Custom Rods (identical to LE5 rods, only 149.5mm in length)

bore = 88mm
compression height = 28mm
wrist pin diameter = 20mm
stroke = 86mm
rod length = 149.5mm
rod ratio = 1.73:1
total bottom end height = 220.5mm

NOTE: I say the above combination is ideal for n/a because if you're using factory LE5 pistons, compression will be up near the 11:1 range if not slightly higher. You CAN use LE5 pistons that lower compression, but this is my reasoning behind saying this would be better for n/a.. plus the rod ratio is a bit higher than the next variation.

2.1 custom piston/ turbo
Ingredients:
-LE5 block
-L61 rods
-LSJ crank
-Custom pistons (Identical to L61, except comp. height = 31mm, and bore = 88mm)

bore = 88mm
compression height = 31mm
wrist pin diameter = 20mm
stroke = 86mm
rod length = 146.5mm
rod ratio = 1.70:1
total bottom end height = 220.5mm

NOTE: I say this one is ideal for turbo because since you are getting custom pistons, you can alter the dome/dish to achieve any compression you want.
Furthermore, this would be a good combination if you have L61 eagle rods hanging around that have not been used yet, and decided to change direction and build an LE5 based engine instead, but still want to use already acquired parts.

which one would be more cost effective depends on what parts you have laying around or have access to, as well as the cost of custom pistons vs. custom rods. Both situations I plan on looking in to tomorrow afternoon.



the reason I'm revising this, is because I recently discovered that the LE5 rods have a tapered end, and the LE5 pistons also have a taper on the inside of their wristpin.

because of this taper, you CANNOT mix LE5 and L61 pistons/rods with one another. GM most likely did this to prevent installation error... or something.

the crank journals and rod journals however across all variants are the same dimensions, so swapping cranks is a no brainer... ASSUMING you take into account that the LSJ crank needs to use an LSJ flywheel and clutch. LE5 and L61 use the same flywheel and clutch, so mixing and matching there is easy.


So NO pistons can be swapped from one ecotec to another
-LE5 wrist pin is 20mm, but taper slot for rod/piston interface
-L61 wrist pin is 20mm, straight slot for rod/piston interface
-LSJ wrist pin is 23mm, straight slot for rod/piston interface
-LNF wrist pin is 23mm, ????slot for rod/piston interface, and also has direct injection dome shape

so mixing and matching IS limited, but you can make some cool 2.1L ecotec combinations using an LE5 block as a good starting point.

this will give you the advantage of having a larger bore (88mm vs 86mm), while retaining lower piston speeds and better rod ratio of the shorter stroke ecotecs (1.70:1 using L61 rods, and 1.73:1 using custom rods are pretty damn good, especially for those looking to build all motor cars... hint hint)







Edited 6 time(s). Last edited Tuesday, January 24, 2012 11:31 PM

edited original post for typos




Edited 1 time(s). Last edited Tuesday, January 24, 2012 11:25 PM

1.73:1... nice. haha.


- Your not-so-local, untrained, uncertified, backyard mechanic. But my @!#$ runs

Great info! Almost makes me want an Eco.


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Shawn McKenzie wrote:Great info! Almost makes me want an Eco.

Same here. I am looking for a 2000+ white shell for an eco swap or build. Great info Paul.

Quit dicking around and finish your car damnit




I have no signiture

I'm guessing that we are assuming that all the blocks are supposed to be the same height but have a 1.5mm tolerance (or more).


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I called a company called R&R connecting rods, and they can make me a custom set of rods for $863. 4340 H-beam, ARP 2000 bolts, and they will copy the rod but with the longer length that I need. For the most part, its not a bad price, and the cool thing is once I order these once from them, they save the dimensions so if anyone else ever wanted to build a similar engine you could just call them up and order them.

Leafy wrote:I'm guessing that we are assuming that all the blocks are supposed to be the same height but have a 1.5mm tolerance (or more).

that is correct.

all the bottom ends total up to right around 220mm, so the deck height must be just a tad bit taller than that.

of course, this could change once I finally get a chance to physically measure an example of each.

Whalesac wrote:Quit dicking around and finish your car damnit

this may be a game changer, just saying :X







Edited 2 time(s). Last edited Wednesday, January 25, 2012 12:57 PM

what do you think the limitations of the 20mm wrist pin would be?


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Boosted2point4 wrote:what do you think the limitations of the 20mm wrist pin would be?

More power than practically anyone will make. Its a hardened steel tube in double shear. You could do the math out to get maximum piston force and determine max power from there. But, its going to be a lot even your cheap as dirt 1018 mild steel has a shear strength (modulus of elasticity in shear) of ~11,400,000 psi (well, its actually the same for all steel, but you get the picture).


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When I build a motor for my cobalt I will be using a my lsj block with zzp block brace/girdle, bored to 88mm, lsj crank, zzp lsj rods, lsj pistons sized to 88mm. This would be the strongest, most cost effective way to make 6-700 hp. Using a LE5 block and these components would be the most cost effective way to make a 2.1l as well which would be good for deep in to the 500s.

ignore my comment i realized my answer this morning after i slept....

I was told the gen2 blocks are actually weaker than gen1s so a lsj block would be your best option if you want big power. I'll let you know how the girdle works out


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Good info as always PJ. Good food for thought for me since my le5 block will be just sitting here a while longer.

then gen II blocks have reinforced webbing and increased cooling capacity. they are considered stronger.

the main focus of this would be if you wanted to build an engine with an ideal rod/ratio or one a little higher than the standard LSJ.

To add to that, based on where the sleeves are held, in the middle for the 1g blocks and at the bottom for the 2g blocks, in theory a 2g block will be stronger than a 1 g block if both were to get the zzp block guard (girdle).


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Well I guess I shouldn't say weaker but more acceptable to failure due to cracking internally between oil and water galleys. This is what I was told by Ryan @ zzp as he had a gen 2 block fail around the.550-600 range where it cracked between galleys.


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pics of this zzp girdle?



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