Unusual cylinder coloration...

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crazedtech85
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Unusual cylinder coloration...

Postby crazedtech85 » Sat Sep 09, 2017 5:39 am

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
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jed
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Re: Unusual cylinder coloration...

Postby jed » Sat Sep 09, 2017 12:26 pm

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
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Re: Unusual cylinder coloration...

Postby crazedtech85 » Sat Sep 09, 2017 1:40 pm

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.

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Re: Unusual cylinder coloration...

Postby modok » Sat Sep 09, 2017 2:14 pm

Cylinder looks lumpy. How was it honed?
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Re: Unusual cylinder coloration...

Postby Norris Marshall » Sat Sep 09, 2017 4:49 pm

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

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Re: Unusual cylinder coloration...

Postby jed » Sun Sep 10, 2017 7:28 am

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
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Re: Unusual cylinder coloration...

Postby crazedtech85 » Sun Sep 10, 2017 11:53 am

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

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Re: Unusual cylinder coloration...

Postby modok » Sun Sep 10, 2017 3:36 pm

Ah, I see. Aluminum+sleeves is always slightly screwy.
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Re: Unusual cylinder coloration...

Postby jed » Sun Sep 10, 2017 7:01 pm

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

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Re: Unusual cylinder coloration...

Postby BILL-C » Sun Sep 10, 2017 7:56 pm

Did you use torque plate when you honed block? If so, what fasteners and torque numbers did you use?
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Re: Unusual cylinder coloration...

Postby CharlieB53 » Sun Sep 10, 2017 9:23 pm

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.


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