Piston hitting spark plug!:(

NokaoiMK3

NokaoiMK3

Drifter..
Jul 27, 2008
275
0
0
Gilbert Arizona
So i daily drive my supra with a pretty stock 1jz on stock twins.. Only mods are y-pipe and down pipe and stinger standalone tuned by tony at ums tuning.. Saturday morning im just leaving my neighborhood car is starting to warm up and as im pulling out on to the main road i start to hear this kinda "Tap, Tap Tap" not a pretty noise but didn't sound like rod knock or anything like that and i could hear it coming from the top of the engine and was relevant to the rpm's.. So not taking any chances i towed it to the shop i work at and got a better look at it.. At first i thought it was mabe a cam cap that came loose as a miss started as soon as the tap started.. Took off the valve cover and nope all is good under there.. So i pulled the engine yesterday thru it on a stand and started tearing it down to find what the eff was going on.. I was hoping mabe one of the twins took a shit, but naw they both looked awesome.. little play and turbines look great.. So i then tore off the oil pan thinking mabe it was rod knock and im retarded.. And i did find about a dime size of metal shavings on my pick-up and in the bottom of the lower pan so i knew i was getting closer and that something defantly took a poop on me.. So took off the #1 rod cap and dam the bearings and crank look like new... Litterally like no wear at all no scratching, nothing.. so alright not the bearings.. I then pulled all the plugs and all of which looked awesome no detonation or fouling and then the #2 plug and it looked ok minus that the electrode strap was pushed closed and it was obvious that it came in contact with what looks like the piston because when i looked through the plug hole it could see a clean spot on the piston just about the size of the tip of the plug.. So shit.. what could cause this? Rod bolts stretched? Rod itself stretched? Wrist pin took a poop? I wanna know what could cause this so when i rebuild and put it all back together this never happens again haha.. I miss driving my baby already and its only been like 3 days haha
 
Clint

Clint

AzSupras
Apr 4, 2005
1,463
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Mesa, Arizona, United States
That's sucks Jake, I haven't herd to many cases like this, from what I've seen in the past when the piston hits the head like that. It was from a spun barring or a broke rod. When you go to rebuild it you could measure everything and see if anything fell out of spec.

Sent from my ADR6400L using Tapatalk
 
te72

te72

Classifieds Moderator
Staff member
Mar 26, 2006
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WHYoming
I'll be the first one to chime in and say this happened to my 88 once on a trip from the other side of the state. I believe it was #5 on my 7m, electrode strap was absolutely smashed to the electrode itself. Swapped out the plug, never had that problem again, but it puzzles me to this day exactly WHAT happened in my case. It was an NA, and I sincerely doubt that pre-ignition could cause enough damage to break a spark plug... could it?

I always just chalked it up to random crap getting into the engine somehow, and getting between the plug and the piston. Not sure of the odds there, only the results in my case.
 
destrux

destrux

Active Member
May 19, 2010
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Sounds like something made it's way into the cylinder and got between the plug and the piston.
 
I

IJ.

Grumpy Old Man
Mar 30, 2005
38,728
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I come from a land down under
Still don't think it's possible Brad, look at the pic then consider the piston is dished in the middle where the plug is.

head6a.jpg
 
NokaoiMK3

NokaoiMK3

Drifter..
Jul 27, 2008
275
0
0
Gilbert Arizona
Wow you guys are on it!!! and IJ you are exactly right.. didn't even think of that.. and destrux is correct on this one..

So looks like one of my intake valve seats came apart on the #2 cylinder.. Damage isnt too bad.. Head will be fine with a little machine work to smooth out the chamber.. and the block looks great and the piston is barely messed up looks like someone scrathed it all over with like a flat head.. So i will do a rebuild new pistons rings bearings and arp hardware.. the thing is is i have a spare 2jz block, crank and rods and have been contemplating the 1.5jz for the torque but its a ge block with no piston squirters.. How important are the piston squirters? Its a daily driver/ weekend drifter..
 
destrux

destrux

Active Member
May 19, 2010
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I ran my eclipse (daily driver) with 250whp for 9 years on a 4G63 turbo build on a non turbo block that had no oil squirters. On a daily driver it would be fine. I ran water injection on that car too... helps alot with combustion temps.
 
airhead04

airhead04

New Member
Aug 21, 2009
1,489
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Lima, Ohio, United States
Oil squirters just allow the cylinder walls to stay cooler with the extra force on the engine from the turbo. Deleting them is a personal opinion type move. Some people say dont, some say do it. Personally, Ive done both and never seen ANY difference. So go with what youd like.
 
NokaoiMK3

NokaoiMK3

Drifter..
Jul 27, 2008
275
0
0
Gilbert Arizona
thanks airhead04 that helps a lot.. I think im just gunna get the head machined and put it back together and get my twins upgraded and rebuilt by albert.. 1.5jz sounds more like when i can afford upgraded pistons and rods.. Oh i got a question.. I think im just gunna get the arp head studs but are the 1jz headbolts re usable?
 
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