can anyone tell me the size of a stock piston out of a 92 gt. how to determine a cast from a forged piston by eyesight (if possible?).thanx
piston size
- Thread starter airbag
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airbag said:
A stock piston will have a diameter of 4.000" ... or real, real close to it (I never mic'd a series of them to be any more accurate with my answer. Oversizes are 4.030", 4.040" and 4.060".
The best way to tell if the piston is cast or not is to look at the appearance of it. A cast piston is made from being poured into a mold and will show prevalent casting marks on the underbelly. A forged slug is made by compressing the material with steel dies that form a solid, near perfect shape.
So in short ... a cast piston looks unrefined and a forged one looks refined.
Do an interet search and picture hunt for a visual.
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87'GTstang said:I have 4.020" pistons going in my engine, thought i'de add one
Who the hell makes 20-over pistons???
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87'GTstang said:
Wow, I didn't realise that many folks waste their time ... excuse me, make a 20-over ... cool.
How is .020 over a waste? Just curious, since it retains more of your cylinder wall, allowing for more boring later on, if the necessity ever comes up 
That's no different than saying "oh, why get a .030 when you could just get .040 or .060?
That's no different than saying "oh, why get a .030 when you could just get .040 or .060?
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StangGT1995 said:How is .020 over a waste? Just curious, since it retains more of your cylinder wall, allowing for more boring later on, if the necessity ever comes up
That's no different than saying "oh, why get a .030 when you could just get .040 or .060?
I suppose in a drag use situation, where you cook things more regularly, having another bore point for a block isn't all that bad .... but I also suppose trying to unshroud a large valve head as much as possible doesn't make much sense either. Ahhh the constraints of the factory spec blocks.
Exactly - my engine had 277k miles on it when pulled. When I miked it out, .020" over cleaned it up very well actually. Why would I want to take off more than is necessary? Yeah there are more options for .030" over out there but the nice thing is that yes, I CAN rebuild my block again if I ever have a problem or it just wears out. Regardless, I still have a damn good piston and the compression that I was after - so who cares that I or others haven't gone .030" over? Besides, these are thin-wall casting blocks, I feel better about the fact that I have more strength in the cylinder walls anywayStangGT1995 said:How is .020 over a waste? Just curious, since it retains more of your cylinder wall, allowing for more boring later on, if the necessity ever comes up
That's no different than saying "oh, why get a .030 when you could just get .040 or .060?
