Well, that is the verdict.
Question: Anyone have any good stock pistons laying around?
Any of the Cali guys that are going to the meet tomorrow? That would be great!
I am not allowed to spend any real money on the car, so IF i could get some stock pistons off someones hands that would really, really help out.
Thanks guys.

Kaiser if you see this: You said I might be able to lift a piston or 2 from you, if so call me @ 909.223.6528 or 909.794.7808. Thanks, don't mean to sound like a cheap ass, but the ol'lady will kill me if i spend more money on a car that is just gonna be gettin sold here shortly.

I am not proud of my accomplishment, just want all to see...



The deal is: My wastegate got loose about 10,000 miles ago, and instead of just putting some hi-temp silicone gasket stuff on there, and something on the bolts so they didn't back out, i just tighten them when I changed my oil, every 2500-3000 miles, depending on time of month. So when it got close to the time to change the oil, I would notice that the boost would slowly creep up from a 5lbs to a 13-15lbs boost. All know that 15lbs is way too much for stock internals.

So there you have it. :(

Ouch. How many miles have you been boosting?

20,000-25,000 miles. Odometer stoped working for about 2 weeks in there some point because the spedo cable got broken.

>weeks in there some point because the spedo cable got
>broken.

There is no speedo cable :-) it's all electronic. You've got a dead speed sensor.

Dino, that is what that little bugger was called.. (HAHA, don't hate me for my ignorance). Well it got fixed at the spedo shop downtown, and they "recalibrated" (or put a different type of sensor in it) to account for my different size than stock tires.

What other damage was there besides the ring lands?

That was pretty much it, everything else looked good.

Any small shiny specs on the cylinder head and valves? What about the tops of the pistons? Any small pits, or small shiny dots?

What about the other cylinders? How did the top rings looks? Did they look intact and smoothe, or was there any pitting?

What were the rod bearing like? Were they worn fairly evenly?

Sorry, I am new at Talons, and kinda interested at the "real" limit of the stock pistons. So far, it seems to me that the top ring just overheated and butted together, seazing in the bore, and hence breaking the ring lands.

This is common with hypereutectic pistons cause they run hotter then forged. The problem is usually resolved by running more fuel, and a bigger ring end gap (was yours stock?). I have a feeling with proper tune, and ring gaps to spec for blown/nitrous applications, these things may take more power and boost then most people seem to think.

Thanks,
Toma

>Any small shiny specs on the cylinder head and valves? What
>about the tops of the pistons? Any small pits, or small
>shiny dots?
Nope.
>What about the other cylinders? How did the top rings
>looks? Did they look intact and smoothe, or was there any
>pitting?
Nope.
>What were the rod bearing like? Were they worn fairly
>evenly?
They look good, all except the number 4 rood bearing looked like it took on some weird wearing.
>Sorry, I am new at Talons, and kinda interested at the
>"real" limit of the stock pistons. So far, it seems to me
>that the top ring just overheated and butted together,
>seazing in the bore, and hence breaking the ring lands.
The stock pistons can handle quite a bit, but i just put too much into them.

>The stock pistons can handle quite a bit, but i just put too
>much into them.
>

Thats exactly what I was getting at. They sound like they can take MORE then you put into them by the sounds of things, so long as the ring gap is correct. Was it factory gap? Anyone know what this is?

Thanks,
Toma

Our stock pistons alone can take quite a bit of boost. Much more than 8 psi. BUT when the engine detonates, that great force will break the first two ring lands without hesitation. Detonation is what cracks piston ring lands, not overboosting. The problem is that with more boot that you run on stock cast pistons, the less detonation they can take. So for example, if the motor detonates pretty good at 8 psi, they may take that abuse a bit. Now, if it detonates at 10 or so psi, then the pistons go bye-bye. We need to run pretty rich under boost to avoid detonation. Under boost timing should not go over 17-19 degrees advance, or detonation can result.

Well sure, but his description of the head, valves, piston tops and other rings does not indicate any detonation.

interesting to say the least. Maybe I ought to boost it instead of the nitrous....hmmm

Toma

>Well sure, but his description of the head, valves, piston
>tops and other rings does not indicate any detonation.
>
>interesting to say the least. Maybe I ought to boost it
>instead of the nitrous....hmmm
>
>Toma

Neither did mine or many others on here with turbos. I heard the nasty rattling, then puffs of smoke was comming out the dipstick and oil catchcan. Mad blowby, cause i cracked the piston ring lands from the detonation. My cylinders and piston tops, and skirts were in almost perfect shape. I only cracked the #4 piston. Replaced it with a used piston and rings, and now I'm still beatin on it at 8 to 9 psi without failure. I ran to lean at 10 psi when that happened. If the detonation was severe enough, and happened frequently, then I would sure think you would see damage on the head and or pistons. Just to be sure everyone's on the same page...Its detonation I'm talking about, not pre-ignition. Detonation occurs AFTER the spark plug fires, which generates more force on the piston rings than anywhere.
From all of the pics of broken pistons from our cars that i have seen, including my own piston, I find it very interesting that they all break ring lands near the same location- on the intake side of the piston....

YAY!!! I TOO only broke piston #4, Dan, Kaiser, or James probibly will be able to produce one good piston, I should be back in buisness by the end of the week!!!

Vinnie(kiku) has some for sale in the f/s forum. Real cheap.


ride__________95 Eclipse RS : 5 speed
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danny, I managed to get aholdof 3 good pistons from james this past weekend. Just hit me up, they are yours...

Check you email.

kaiser

Kaiser, Dan, James... All you SoCal guys who are helping me out... THANKS a bunch.
It pays meeting people at 2gnt meets... Take my advice all, you should meet your fellow 2gnters!!!