Piston detonated?

papajoewill

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Hey Bs and Gs,

So I have a photo from my boroscope from November and then again from two days ago. I haven’t gotten on the car or beat it too much since getting it all back together around October. I got the battery light after one little test hit and then didn’t get on it again. I got my alternator back from J2Fab after an upgrade (great folks over there) and installed it then ran around again but not too hard. A pull here and there but nothing crazy. Idk what made me check but I sent the boroscope back in and my stomach dropped. I think I see that spot getting bigger and my simple question stands, is my piston ripping it self apart due to detonation or something else?

This is from November.
IMG_2072.jpg


This is recent.
IMG_2076.jpg


I apologize it’s not perfectly centered but you can obviously see those marks on the side of the piston.

I bought what was supposed to be a stock long block and then when I cracked it open I noticed the pistons weren’t stock. So far it’s ran like a top. Quiet and makes excellent power but here we are as always lol. Nothing would’ve made me check other than the extreme paranoia from my first motor go around.

Before it’s the first comment, I immediately did a compression test and everything was solid there. Haven’t done a leak down test yet.

Should I not romp it while I’m concerned? I have a vampire knock system on my bench but haven’t installed that since installing the MS3 PNP. Should I install that or get the stuff I need for the MS3 to do it?

Im already planning a big boy motor build but would hate for this one to let go because I’m being impatient. Any input is welcome. Happy Sunday hombritos.
 

Albatross

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It definitely looks like it's gotten worse. I think you may be on the right track thinking detonation/pre ignition is causing it. You may have a partially clogged injector. If it were my car, I would play it safe. If you get into it and that cylinder decides to go really lean that weak spot in the piston could give way and boom! Just my 2 cents.
 

papajoewill

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IMG_2099.JPG


I stuck in my scope with resolution updated to the max. Looks a little better after a pull lol. Thug life gentleman. Another short block is about to be purchased for a deal and a half. 0 miles from a builder I trust. Supposed to hold 800 wheel and then I’ll get a “final” motor built i think. Debating what heads to pop on it just to be safe but I have a video I’ll upload momentarily.


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papajoewill

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What kind of horoscope is that and how much do those generally run?

Just a little amazon special made by DEPSTECH. I have the one with the yellow cord. The one with the highest resolution wouldn’t fit through the spark plug hole so I got the next best one. I love owning it. Used it around the house more than I thought too. Not too expensive for what it does.
 

papajoewill

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One of my friends said carbon build up but the scoring on the cylinder wall makes me think otherwise. Can still see cross hatching on the wall so idk if that means it’s not that bad? Still weird but will keep an eye on it.


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papajoewill

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Damn, the photo quality is great! Impressive

Once you get past this, whether it needs a rebuild or not....get it on E85. 99.99% chance none of that would have happened. Liquid gold is well documented as a ruthless destroyer of coronavirus
I bought the motor used and didn't boroscope before accepting delivery. Didn't even own one. I suspect it was there from before but regardless it's there now more and maybe bigger lol. I'll send a pic of more guts soon to see E85 is absolutely the plan. Will probably use this motor to test the fuel system and all that jazz before any other motor is subject to my hands.
 

papajoewill

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IMG_2109.jpg


So one group of thought from folks I trust say it looks ok?

I’d love to see the inside of other folks motors to see how mine compares honestly.

Who knows really... corn juice and power incoming regardless :)
 

01yellercobra

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In my experience detonation leaves pock marks on the piston. Depending on how bad it is at least.

Honestly, and I'm no pro, it doesn't look bad to me. To me it just looks like a reflection moving around. Was it making noises? Did you see smoke or something?
 

papajoewill

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In my experience detonation leaves pock marks on the piston. Depending on how bad it is at least.

Honestly, and I'm no pro, it doesn't look bad to me. To me it just looks like a reflection moving around. Was it making noises? Did you see smoke or something?
The very occasional puff of smoke on start up after sitting for a week but otherwise not at all. Still pulled hard AF on my way home before I checked and then I think the paranoid side of me just immediately freaked out to be honest when I saw it. It's such a quiet motor, even when making power still. And the power feels right if you know what I mean. I'll take a video of it running as soon as I can but no noises or smoke. Compression test was also great on all 8 cylinders.
 

papajoewill

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In my experience detonation leaves pock marks on the piston. Depending on how bad it is at least.

Honestly, and I'm no pro, it doesn't look bad to me. To me it just looks like a reflection moving around. Was it making noises? Did you see smoke or something?
I drove it St. Aug and back from Jax to kind of shake everything down as well as break in the brakes and it was ultra quiet. No indication/noise/smoke/loss of power etc. I have a buddy with a dyno locally I may take it to and make a small baseline pull to see where everything is.
 

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