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Thread: Well... here was the culprit

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2009-04-19 22:20:13
Well... here was the culprit
So a few of you know that I have had problems with my DET. Had it running fine, and then it started bogging down sometimes so I changed the oil and took the spark plugs out, instantly realizing that the 2nd cylinder spark plug tip was blown off. I ignored it, and thought "Oh, maybe it blew out the back somehow, without causing any damage"

So, the car sat for a month or so waiting for the weather to get better. It was a beautiful weekend out, and decided to take the head off and see what I can see.

I took the head off, and instantly realized what had happened.

Take a look for yourself

Does anyone have any ideas on what I should do to prevent this from happening on my next build?

By the way, I was running 14lbs T25 turbo and NGK7es11 spark plugs
2009-04-19 22:20:40
Wow, didnt realize how damn big the picture was.... sorry about that
2009-04-19 22:33:10
Piston 1 looks okay. Piston two is obviously toast. Piston 3 looks like it has quite a bit of detonation damage as well. If that's the source of your problems (detonation) then to prevent it in your next build I suggest a bigger turbo (T25 at 14 psi is your main problem) among other things.
2009-04-19 22:35:14
Yeah, I was also thinking about peaking at 10lbs on the t25 for my next build. It ran fine at 14lbs for a while, so I think i'll just run between 8-10 and then if I go to the track turn it up to 12-14ish.

It was detonation too, I took the spark plugs out the other day when I started to take the head off and #2 and #3 were soaked in oil. 1 and 4 were fine. It's weird, on #2 though, it looks like the piston rings pretty much welded themselves to the side of the cylinder.
2009-04-19 22:38:48
When I saw #2 piston I yelled KABOOM!! My room mates ran into my room to see what had happened... they couldn't see what was wrong in the picture.

I fully endorse BenFenner's product and/or service.
2009-04-19 22:55:44
lol told ya so, haha, yeah you definetly had detonation. If you look at not just the melted #2 piston look at the number 3, there is detonation damage both on the piston and on the top of the block close to the firing ring surface. Its pitted. That is what happens, again been there done that. Yeah if you wanna run 14 psi definetly get a bigger turbo. Its just too much for the motor to handle as far as heat goes.
2009-04-19 23:20:53
the piston on the far right looks like it has some small groves from valve-piston contact or is that just from the pic?
2009-04-19 23:22:30
Were you running 370's at 3 bar with a stock MAF?
2009-04-20 04:51:34
Sniff. RIP.

When you get er fixed I will stop being sad.

That really sucks. So this was only 14psi on a T25? I didn't think that was too much but boy am I wrong. Ive seen guys run up to around 16psi around here before. But that was just cheating death lol.

Go bigger
2009-04-20 09:45:49
No it was a Maxima MAF, and... they werent stock injectors (I forget what they were now)

Now, on to my next question. Would a T28 fit the same manifold as a T25? I'm probably going to get a new motor through Andreas, but I wanna know if I should get a 28 to put in it and if it will be any harder to do.
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