Unusual cylinder coloration...

[crazedtech85]

2017-09-09_05.32.48.jpg

Lets start with some motor specs I feel are important for my ?

LS3 417ci stock aluminum block @ 4.070 bore
12:1 comp
12.5psi boost e85 supercharged
-Ceramic coated pistons and combustion chambers
-Wiseco pistons with ring pack they come with gapped of coarse...
-car is 2006 corvette and made 840whp on dynojet std correction

On attached pictures note the coloration on the cylinders, in trying to find info on what caused this I've never seen this before. I have my own theory's and concerns but want to hear your thoughts. Also there is some build up on the pistons and I am betting its not only from oil but related to the cylinder coloration. Only reason I am pulling motor is because looking with bore scope I thought I seen the pistons starting to melt but its looks completely different with heads off now haha. Plus customer wanted refresh anyhow he said the car was running awesome though and has no signs of a issue

2017-09-09_05.34.13.jpg

[jed]

Please be more specific on what color you are referring to and where in the cylinder.
Yes piston top shows oil contamination.
I am still wondering why u tore the engine down. Engine was running good, made good power, no smoke and was not using oil,
no noise.
John

[crazedtech85]

Was using some oil but again we thought the pistons had started melting because the spots on edge of pistons that oil residue was chunked off looked like pitted hot aluminum on the bore scope. customer wanted to pull it apart for inspecting, bearings and such anyhow to make sure its all going to be good and ready for next season. But the color I'm referring to is the gold what looks like hot spots on cylinder walls.

[modok]

Cylinder looks lumpy. How was it honed?

[Norris Marshall]

Looks like hone chatter and or not enough stock removed by hone.

[jed]

The yellow color yor are referring to could be the cylinder has glazed over.
Being a old timer it used to be a real problem and rembering in my minds eye a glazed
Cylinder had that yellow tint to it.
We don't hear much about glazing much any more. But I suppose it can still happen.

[crazedtech85]

It was honed with manual hone machine not the cheap drill type but actual machine I've done many motors this way never had this till now but this is only the second one with aluminum block iron sleeve making this kind of power the other one made 20hp less but after some 3000mi map sensor blew out of its hole and it ran it lean during a pull mashing pistons against cylinder walls so that one ended up scored never noticed these spots on it though but we replaced block, pistons and shortened the stroke from 4.100 to 4in and now this confusion...I took it apart more last night and pistons and rings look normal except the oil its burning on top. Going to get bores measured after I finish pulling it all apart Monday. Look for if its uneven but I'm kind of wondering if for some strange reason these rings can't hold the cylinder pressure or if block isn't dissipating the heat fast enough in spots from the walls and its creating hot spots. I reviewed the tune he had done and it was leaner than I preferred at low to medium boost so would have gotten a little hot I'm sure during combustion. Idk just trying to figure it out before I go reassemble haha

[modok]

Ah, I see. Aluminum+sleeves is always slightly screwy.

[jed]

What do the combustion chambers look like. Show us a picture please.
The ceramic coating may have something to do with how they look.

[BILL-C]

Did you use torque plate when you honed block? If so, what fasteners and torque numbers did you use?

[CharlieB53]

Curious to know just how thick is the alum deck? How far down that sleeve is alum and at what height is the cooling water/fluid? Are you using any of the water wetter products to improve cooling?

Also very curious where the oil is coming from. I don't readily see indications of leaness but the oil could be masking the coloration of the dome/combustion chambers.

[crazedtech85]

Sorry for the delay... Just got back to responding, anyway I got the block all torn down and started measuring. It turns out it just couldn't handle what we threw at it. The bores were out of round and distorted in some cases as much as .0021 the block was shaped like a banana with the center main bearing worn on the lower half and the outers worn on the upper half even with my clearance set at .003 and the cam bearings also showed the same wear. As for the head and deck surface they to were warped .002-.003 in banana fashion as well haha. Guess i was correct when i told the customer while assembling it that it wouldn't hold for long and he should get a iron block... he didnt want to for weight reasons, well now it has a iron block haha putting it all in by the end of the week.

[crazedtech85]

Another side note to the proof of blowing past the walls. with the iron block and slightly less overall disc the motor made a significant amount more power considering the lack of changes as follows.

__________ Aluminum block_____Iron Block
bore___________4.070 ___________4.030
compression____11.8:1____________12:1
boost@6800rpm__12.6psi__________12.9psi

so on the dyno we show a solid 40hp across the board gain with the iron block number came in as follows with iron block dynojet dyno

std correction__________sae
_887.53hp________866.99@6700rpm
_737.04tq________719.99@55005pm

BTW the car sounds so much more crisp now like as if i added 2 points of compression haha

[In-Tech]

Lets start with some motor specs I feel are important for my ?

LS3 417ci stock aluminum block @ 4.070 bore
12:1 comp
12.5psi boost e85 supercharged
-Ceramic coated pistons and combustion chambers
-Wiseco pistons with ring pack they come with gapped of coarse...
-car is 2006 corvette and made840whp on dynojet std correction

Just noticing your last post said it made 740 not 840 like the first post in this thread, no biggie or which one is the typo?. I am curious if you are running a MAF and if so, did you log the grams per second?

[crazedtech85]

I don't think i ever said 740whp but if i did that was a typo it made 840whp std on discolored motor, new iron block one gained 40+whp std across the board. perhaps you looked at tq? idk lol dont matter. as for the grams it's not going to be at all accurate id imagine being it has different scaling from correction factor and such but i think it sees like 511gps give or take. I don't deal with much of that part of things this guy has a separate tuner but would like to get more involved in that next year for learning sake. I will be doing some hp tuner stuff on a twin 88mm boosted car soon but that's a whole nother topic