what do you think happened? sr20det torn down - Zilvia.net Forums | Nissan 240SX (Silvia) and Z (Fairlady) Car Forum

joe3180 · 05-21-2013, 06:50 PM

What are you thoughts on what caused this?

Im just happy the cylinder wall wasn't too bad.

s13 sr20det #4 piston everything else a-ok besides the piston bits in the oil pan.

New pic...

joe3180 · 05-21-2013, 06:51 PM

first thoughts are leaky injector...

R@ddy · 05-21-2013, 07:07 PM

Extremely lean on that cyl.

joe3180 · 05-21-2013, 07:38 PM

Really...you think so? I would have thought if that were the case the piston would have melted more toward the center or at least more than it did, instead of just that little area.

oni jake · 05-21-2013, 09:01 PM

We've done the same thing just last summer. Never did figure out %100 what caused it. If its not a mechanical failure, such as a leaky injector, the blame is in the tune.

We rebuilt afterwards and the entire gallery is here: https://www.facebook.com/media/set/?...6820932&type=3

cotbu · 05-21-2013, 09:03 PM

That piston should be the zilvia.net official troll face!

ShadowMan · 05-21-2013, 09:53 PM

Judging by the one picture, that piston looks pretty light grey/whiteish on top, which would lead me to believe you leaned out on that cylinder. #4 cylinders seem to be pretty notorious for running hotter than the others. Same thing happened to me, shitty tune is to blame for sure, at least in my case. I'm by no means saying it isn't a leaky injector, but I would imagine it would be blacker if that was the case. I'm also not a pro engine builder either, so there's that. Might as well check the injector and the tune.

joe3180 · 05-21-2013, 10:03 PM

in person the top is fairly black with a crust of burnt oil. I think the flash just made it much lighter than it really is. Ill put up another picture of it later tonight where the flash isn't bleaching it out.

steve shadows · 05-23-2013, 11:33 AM

It's usually a shotty wiring harness where that injector driver is cutting out intermittently. Good wiring and good contact on all pins to outputs and inputs on sensors and drivers is the most important thing next to the actual tune on the car.

joe3180 · 05-23-2013, 11:35 AM

thanks for the input. Well good thing I got a new wiring harness since this happened so if it was that, it wont happen again or shouldn't.

05-21-2013, 06:50 PM	#1
joe3180 Zilvia Junkie Join Date: Aug 2005 Location: 909 california Posts: 356 Trader Rating: (11) Feedback Score: 11 reviews	what do you think happened? sr20det torn down What are you thoughts on what caused this? Im just happy the cylinder wall wasn't too bad. s13 sr20det #4 piston everything else a-ok besides the piston bits in the oil pan. New pic... Last edited by joe3180; 05-21-2013 at 10:39 PM.. Reason: added second pic

05-21-2013, 09:03 PM	#6
cotbu Post Whore! Join Date: Sep 2005 Location: SWFL Age: 50 Posts: 3,318 Trader Rating: (3) Feedback Score: 3 reviews	That piston should be the zilvia.net official troll face! __________________ LoverTechnologies "Half Broken Things!"

05-21-2013, 09:53 PM	#7
ShadowMan Zilvia Junkie Join Date: Jul 2011 Location: oceanside, CA. Posts: 538 Trader Rating: (4) Feedback Score: 4 reviews	Judging by the one picture, that piston looks pretty light grey/whiteish on top, which would lead me to believe you leaned out on that cylinder. #4 cylinders seem to be pretty notorious for running hotter than the others. Same thing happened to me, shitty tune is to blame for sure, at least in my case. I'm by no means saying it isn't a leaky injector, but I would imagine it would be blacker if that was the case. I'm also not a pro engine builder either, so there's that. Might as well check the injector and the tune. __________________ in any situation....thou shalt blaze

05-23-2013, 11:33 AM	#9
steve shadows Post Whore! Join Date: Aug 2003 Location: LA and OC Posts: 8,202 Trader Rating: (5) Feedback Score: 5 reviews	It's usually a shotty wiring harness where that injector driver is cutting out intermittently. Good wiring and good contact on all pins to outputs and inputs on sensors and drivers is the most important thing next to the actual tune on the car. __________________ Like Me on FaceBook !

05-21-2013, 06:51 PM	#2
joe3180 Zilvia Junkie Join Date: Aug 2005 Location: 909 california Posts: 356 Trader Rating: (11) Feedback Score: 11 reviews	first thoughts are leaky injector...

05-21-2013, 07:07 PM	#3
R@ddy Nissanaholic! Join Date: Jul 2008 Location: SoCal Age: 35 Posts: 1,632 Trader Rating: (32) Feedback Score: 32 reviews	Extremely lean on that cyl.

05-21-2013, 07:38 PM	#4
joe3180 Zilvia Junkie Join Date: Aug 2005 Location: 909 california Posts: 356 Trader Rating: (11) Feedback Score: 11 reviews	Really...you think so? I would have thought if that were the case the piston would have melted more toward the center or at least more than it did, instead of just that little area.

05-21-2013, 09:01 PM	#5
oni jake Zilvia Junkie Join Date: Sep 2007 Location: ---------- Posts: 416 Trader Rating: (5) Feedback Score: 5 reviews	We've done the same thing just last summer. Never did figure out %100 what caused it. If its not a mechanical failure, such as a leaky injector, the blame is in the tune. We rebuilt afterwards and the entire gallery is here: https://www.facebook.com/media/set/?...6820932&type=3

05-21-2013, 10:03 PM	#8
joe3180 Zilvia Junkie Join Date: Aug 2005 Location: 909 california Posts: 356 Trader Rating: (11) Feedback Score: 11 reviews	in person the top is fairly black with a crust of burnt oil. I think the flash just made it much lighter than it really is. Ill put up another picture of it later tonight where the flash isn't bleaching it out.

05-23-2013, 11:35 AM	#10
joe3180 Zilvia Junkie Join Date: Aug 2005 Location: 909 california Posts: 356 Trader Rating: (11) Feedback Score: 11 reviews	thanks for the input. Well good thing I got a new wiring harness since this happened so if it was that, it wont happen again or shouldn't.