L03 Stock pistons; Dish or flat top?

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Aug 4, 2003 | 12:57 PM
  #1  
well....anyone know???
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Aug 4, 2003 | 01:15 PM
  #2  
should be dished
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Aug 4, 2003 | 02:01 PM
  #3  
My pistons are flat. The only indents they may of had were for the valves.
This is the only picture I have handy.
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Aug 4, 2003 | 02:32 PM
  #4  
i swear i think mine were dished, but then again that may be wishful thinking.....but i remember heading to clean gasket crap out from the edges of the pistons and i THINK i recall seeing an edge there, .....its not worth ripping the heads off to find out either lol.....even though i MAY have to do this nayways due to the head swap and an oil leak near the firewall somewhere.....i just took the intake manifold off and put new gaskets and so much rtv around the front and back rails its not even funny, ...didn tput any near the intake ports, just all around the coolant passages. also replaced the valve cover gaskets, im gonna feel really stupid if i have to take all the crap off i already took off today...again...fore the third time....heh
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Aug 4, 2003 | 09:43 PM
  #5  
They were all flat top with 4 valve reliefs.
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Aug 4, 2003 | 11:28 PM
  #6  
doh, and i still have an oil leak...valve cover maybe bent, who knows....ill check tomarrow, im pretty much fed up with this by now, but ill forge ahead, seek out the problem, and correct it.
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Aug 5, 2003 | 12:54 AM
  #7  
heh well, i was performing a usual oil change , and drained the oil, pulled the filter , yadda yadda, went to pput new oil in...and i hear it hitting the cardboard i have under the car, so i look, sure enough 1/4 the oil i was putting in the head was instantly commin gout...so im lik ewtf....it has to be the head, ..pour more in and roll under the car real quick with a flashlight to take a peak......oil was pouring out the valve cover gasket, so i pray thats the culprit....yanking the heads off would just Suck.

so i guess im going to go get new valve covers seeing how they are bent and i never noticed it....so now i have an excuse to get those spiffy chrome valve covers ive been looking at. ...yay
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Aug 5, 2003 | 05:22 AM
  #8  
Quote:
spiffy chrome valve covers
You must enjoy working on leaks all the time.

Don't do that if you want your oil to stay in. And don't buy from the low bidder, no matter what the material, you'll end up with garbage that way.
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Aug 5, 2003 | 09:34 PM
  #9  
This might clear things up.

http://www.cardomain.com/member_page...414_7_full.jpg

http://www.cardomain.com/member_page...414_8_full.jpg
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Aug 5, 2003 | 10:09 PM
  #10  
thank you!!! finally a pic! those....are dish. i though i remembered mine being dish, that made my memory clear up. thank you...now moderator, close the post!! lmao
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Aug 6, 2003 | 05:38 AM
  #11  
I am not well educated in piston technology, so why is one better than the other?
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Aug 6, 2003 | 11:15 AM
  #12  
dish isnt really a good thing. but in my case it is due to the fact that i used thicker head gaskets.

by all means flat top pistons are better.
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Aug 6, 2003 | 11:17 AM
  #13  
Quote:
Originally posted by SlowMaro
dish isnt really a good thing. but in my case it is due to the fact that i used thicker head gaskets.

by all means flat top pistons are better.
Do you mean thinner head gaskets?
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Aug 6, 2003 | 11:57 AM
  #14  
no i used .045 head gaskets. i heard that its *ok* to use those if you have dish pistons, however you should use .015 is you have flat tops due to the *quench*?? i dunno. just what i heard.
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Aug 6, 2003 | 12:45 PM
  #15  
Quote:
Originally posted by SlowMaro
no i used .045 head gaskets. i heard that its *ok* to use those if you have dish pistons, however you should use .015 is you have flat tops due to the *quench*?? i dunno. just what i heard.
You got that backwards.

With flat tops you can get away with thicker gaskets. Thicker gaskets are less prone to leak from imperfections in the surfaces.

With dish pistons you can use a thinner head gasket without reaching un-streetable octane levels, something they may not be possible with flat tops.

The quench area is higher with flat tops compared to conventional dish pistons. There are, however, dish pistons that put the dished area ONLY under the combustion chamber. This would premote maximum squish, optimizing the quench area and the benefits of it. Those dished pistons should also be used with thinner head gaskets.
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Aug 6, 2003 | 01:07 PM
  #16  
so should i go rip the heads off this car now and blow 50 bucks on head gaskets or just not worry about it
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