Ok car is an audi 90 coupe with 3B swap car was smoking a bit and overheating now that we looked in cylinder 5 with the mini cam the piston shrunk is this common?
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There are two choices in life-Take it or leave it ! -
if you have a camera is it possible for you to get some pictures? -
well i'm not sure whats happened here but metal cant shrink.....well, not enugh for yo to be able to see or notice, if you've had overheating nd it only the 1 cyinder maybe you've been running lean and its gotten so hot the piston has melted?? as said i think i picture would be the best thing...
Ant91' Coupe quattro 20v - project
KW V2s and other goodies
now gone
03' BMW 330CI - Sold
08' A5 Coupe 3.0l tdi quattro - Sold
57' BMW 525d M Sport TouringComment
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does sound a bit wierd? could it just be the lip of the piston-sidewall that the camera's magnifying?Comment
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perhaps a blown piston ring?? not sure if that would cause overheating tho.....
Ant91' Coupe quattro 20v - project
KW V2s and other goodies
now gone
03' BMW 330CI - Sold
08' A5 Coupe 3.0l tdi quattro - Sold
57' BMW 525d M Sport TouringComment
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You do realize that pistons are ALWAYS smaller than the cylinder bore don't you? It's the rings that take up the gap. Your camera would show the top of the piston sitting back from the cylinder bore. This is normal. There is/was no shrinkage. You get that from going swimming in Lake Ontario in the winter.RS2'd 93 UrS4 5 spd sedan
94 UrS4 V8 6 spd manual avantComment
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piston melts and shrinks
S2 Coupe fully built.
10.9 1/4mile 0-100 in 3.5secs
Precision 6262 turbo
The Green MonsterComment
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Thanks for the pic thats exactly what it is. And yes I know the piston is smaller than bore. Car was running lean melted and shrunk the piston. Time for rebuild
There are two choices in life-Take it or leave it !Comment
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check your injector, if its just the one cylinder thats getting that hot it would seem like a faulty injector??
Ant91' Coupe quattro 20v - project
KW V2s and other goodies
now gone
03' BMW 330CI - Sold
08' A5 Coupe 3.0l tdi quattro - Sold
57' BMW 525d M Sport TouringComment
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Yup its just that one piston thats like that the others are fine. But yes i will check the injector.There are two choices in life-Take it or leave it !Comment
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It look to me as there has been some detonationAelredComment
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Looks like det allright.
The sandblasted appearance gives it away and it`s melted the piston away aroud the edge, and there`s no melting infront of the cool inlet valve.The ONLY S2 Golf!
http://www.s2forum.com/forum/showthread.php?t=19402
10.42@138mph
https://m.youtube.com/watch?v=0wnkkOfFpXgComment
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that picture isnt of his pistion is it?!?! thought it was just for reference....
Ant91' Coupe quattro 20v - project
KW V2s and other goodies
now gone
03' BMW 330CI - Sold
08' A5 Coupe 3.0l tdi quattro - Sold
57' BMW 525d M Sport TouringComment
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So what do we see in the pic, one new gap in the upper left and one in the lower rigth corner,
and some diffuse edge at the left lower section of the piston.
I think the upper right corner leads towards the inlet..
So detonation may be the reason for the diffuse edge in the lower left, but what causes the big gap in the upper left?
Do I get it right?
'93 Audi S2 Avant panthero black, 412.000km
'94 Audi S4 C4 Avant 303Tkm, KW, Brembos, BN-Pipes, Bose, S6 front (sold)
'93 Audi S4 C4 Avant, 260Tkm
'88 Audi 100 Avant turbo 44Q
'84 Audi 80 quattro tornado red
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