Thumper Posted November 16, 2005 Share Posted November 16, 2005 I removed my oil pan and found four of my pistons with the exact same damage. They were all broken on one side only and only on the passenger side of the engine. This is picture of a stock like piston and I have shaded the part that is broken off. Last time I checked the engine had good compression and it had no rattling noises from the bottom end. I can still see the cross-hatching on the cylinder walls. So what caused this? And how will it effect the engine? Only thing I can thing of it effecting is the balance of the piston and maybe oiling of the piston in someway. Thanks P.S. I borrowed this picture from the members gallery if it is yours and want it removed please let me know. Quote Link to comment Share on other sites More sharing options...
Warren Posted November 16, 2005 Share Posted November 16, 2005 Welcome to the wonderful world of DETONATION... What you have there is a piston with the skirt broken off...usually, but not always caused by detonation. When the piston is on it's way up, and gets the shock from detonation of fuel igniting before the intake valve closes and the plug fires, it gets rocked in the cylinder. Due to the clearances between the cylinder wall and the piston side itself, the skirt gets broken off when the piston actually gets cocked in the cylinder. The bottom edge of the skirt being the farthest part from the wrist pin, it gets broken off... I found 2 of these in my oil pan right after hearing the popcorn sound of PING. Check your oil pan real well, even between the bottom of the pan and the baffle in the rear of it, you'll find it. Here is a pic of one solution...omit the skirts on the next set of pistons. Stock ZX Turbo Piston on left...Custom ROSS piston on the right. No guarantee against detonation, but at least you won't be breaking skirts off should it happen. Quote Link to comment Share on other sites More sharing options...
Thumper Posted November 16, 2005 Author Share Posted November 16, 2005 Dang didn't even think detonation could cause something like this but it makes sense. I found all four pieces in my oil pan as well as some metal shavings. I throughly clean it out. I am planning to build up another engine I just didn't want to do it so quickly. For now though I have to run my engine like this so what problems will this cause? Quote Link to comment Share on other sites More sharing options...
Warren Posted November 16, 2005 Share Posted November 16, 2005 If it happens again, you'll probably find a hole in the side of the block with a rod sticking out of it...besides that, you'll probably have a vibration from a now unbalanced rotating mass. That's about it. I happen to have a set of STOCK 86mm pistons here if you need them...Brand new with rings and wrist pins. I've also got a new set of LZ22S 87mm pistons...neither are forged, but they're available... Quote Link to comment Share on other sites More sharing options...
Guest ON3GO Posted November 16, 2005 Share Posted November 16, 2005 will cause a not so balanced engine.. other then that really thats it. it will wear out the cylinder walls un-even but if ur gonna do the other motor like u said then who cares. werid huh ted!.. man i cant believe ur car pulled that hard with a not so good engine lol. mike Quote Link to comment Share on other sites More sharing options...
Thumper Posted November 16, 2005 Author Share Posted November 16, 2005 If it happens again' date=' you'll probably find a hole in the side of the block with a rod sticking out of it...besides that, you'll probably have a vibration from a now unbalanced rotating mass. That's about it. I happen to have a set of STOCK 86mm pistons here if you need them...Brand new with rings and wrist pins. I've also got a new set of LZ22S 87mm pistons...neither are forged, but they're available...[/quote'] Thanks but if I replace the pistons i'm going forged. My new turbo would except nothing less:twisted: Quote Link to comment Share on other sites More sharing options...
Thumper Posted November 16, 2005 Author Share Posted November 16, 2005 will cause a not so balanced engine.. other then that really thats it. it will wear out the cylinder walls un-even but if ur gonna do the other motor like u said then who cares. werid huh ted!.. man i cant believe ur car pulled that hard with a not so good engine lol. mike Well i'm going check the compression again just to see if its low and then she run till she puts a rod through the block. Funny thing is I think this happened when I first got this running. I think it happened when I had my volvo intercooler on. Quote Link to comment Share on other sites More sharing options...
PeterZ Posted November 16, 2005 Share Posted November 16, 2005 Detonation is a strong possibility. Did you find anything in the pan? I have seen the skirts broken like that when a piece of oil pan baffling broke off and the crankshaft kept throwing it around. The pass side of the piston is on the leading edge of crank rotation. That skirt is designed for that type of piston and its expansion rate, etc. I would expect some "accelerated wear" should you continue. Quote Link to comment Share on other sites More sharing options...
Guest Cronic Posted November 19, 2005 Share Posted November 19, 2005 same **** happened to mine, way before i began to up the boost. It's happened on every turbo Z motor I've seen. It's very common, and not a big deal. Mine had 180K miles on them like that with 145 compression across the board. Quote Link to comment Share on other sites More sharing options...
240hoke Posted November 19, 2005 Share Posted November 19, 2005 Yup happened to me. Happened due to broke ring lands though. Ring land broke loosened everythign up and caused some slap. Like mentioned before most aftermarket pistons dont have that little piece there. My JE's are short little things. Quote Link to comment Share on other sites More sharing options...
Tony D Posted November 19, 2005 Share Posted November 19, 2005 Beware of the myth that forged pistons cure all! They will break just as easily as cast when confronted with the forces of detonation! Fix your detonation, find it's cause, THEN make the change to forged. Otherwise you may be withdrawing far more funds from your bank than you ever thought you would spend on "bulletproof pistons"! Quote Link to comment Share on other sites More sharing options...
srgunz Posted November 19, 2005 Share Posted November 19, 2005 Last time I saw that was on a friends Hi-Po ford 289 with forged pistons and 4 down draft webbers. It was built with just too much bucket to cyl wall clearence. After that was corrected all was well. Quote Link to comment Share on other sites More sharing options...
speeder Posted November 20, 2005 Share Posted November 20, 2005 2 factors: 1. excessive piston to wall clearance (Due to wear) allowing pistons to rock, and .... 2. detonation. Heed the universal and conventional wisdom put forth by TonyD: Fix your detonation, find it's cause, THEN make the change to forged. Otherwise you may be withdrawing far more funds from your bank than you ever thought you would spend on "bulletproof pistons"! Those who think that this is no big deal with the L28ET have a rude awakening coming. For those newer members who may have missed this: http://forums.hybridz.org/showthread.php?t=81787&highlight=Weapon Don't be like me and learn the hard way. Quote Link to comment Share on other sites More sharing options...
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