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Location:
Melbourne
Registered:
November 2003
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2T Piston Identification
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Mon, 26 April 2004 10:39
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Hi Folks,
I'm rebuilding my 2T at the moment and I'm looking for some help in figuring out what Pistons are being used in the motor. I did notice there is a number moulded on the side of the piston. I'm wondering if anyone can tell me what this number means...
I have 2 that say 55 and 2 that say 75. Also, I have another one from a different motor that says 35. My immediate thoughts were that they were a size and that the 55 and 75 were oversized. I measured one of them with verniers but it didn't seem to be over the 85mm diameter.
Also, I noticed a couple of numbers stamped into the crown. The pistons I have range from 2 - 4 and from B - D. What do these numbers/letters mean? My workshop manuals have no info on these codes at all.
Any help would be appreciated.
Cheers,
Dan
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Location:
Melbourne
Registered:
November 2003
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Re: 2T Piston Identification
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Mon, 26 April 2004 22:39
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Just talked to an Engine reconditioner and his suggestion was that the numbers were just production identification marks.
Does anyone have any examples of what identification marks an oversized piston carries?
Cheers,
Dan
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Location:
South Australia
Registered:
July 2002
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Re: 2T Piston Identification
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Mon, 26 April 2004 23:17
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Usually it's just on top of the crown of the piston...a number like 40 or 20 or whatever? I don't have any examples on me atm though.
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Location:
Melbourne
Registered:
August 2003
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Re: 2T Piston Identification
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Tue, 27 April 2004 05:43
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Bump for subscribe, interested too.
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Location:
Laverton, Vic
Registered:
July 2003
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Re: 2T Piston Identification
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Wed, 28 April 2004 13:35
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| Quote: |
Usually it's just on top of the crown of the piston
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This is correct.
The identafacation are numbers are
.25 = 10 thou
.5 = 20 thou
.75 = 30 thou
1.0 = 40 thou
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Location:
Melbourne
Registered:
November 2003
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Re: 2T Piston Identification
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Thu, 29 April 2004 01:25
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Thanks Wombat
I'm convinced now that my pistons are standard size which is a relief considering I ordered a set of rings before checking. That'll learn me 
Cheers,
Dan
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Location:
Christchurch, New Zealand
Registered:
March 2004
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Re: 2T Piston Identification
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Thu, 29 April 2004 01:44
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in reference to the 1,2,3,4 numbers,
Just from observation these numbers will be stamped all over the motor, on the deck of the block beside each cylinder for example, and the rods, on the mains and big end caps etc.
Anyway as far as I know this is some form of factory tolerance number, however I could be wrong, just what im led to believe...
Im not sure but i think 1 is best and 4 is worst...
Anyone please feel free to step in and correct me 
Logan
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Location:
Melbourne
Registered:
November 2003
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Re: 2T Piston Identification
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Thu, 29 April 2004 13:18
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I saw something like this in a document about the 4AGE. Is this a manufacturing tolerance/clearance thing?
I also discovered that the rings I got are too thick. 
I have 2 sets of pistons. The motor I'm currently rebuilding has pistons with ~1.5mm thick compression rings and 4mm oil ring. The 'spare' motor's pistons have 2mm thick compression rings with the 4mm oil ring.
It boggles the mind as to why something like that would be. I can only assume that the piston changed over time during the car's manufacture period (later 2Ts had thicker rings for example) or one of the sets of the pistons are aftermarket.
If anyone has any info on this I'd be keen to know.
Cheers,
Dan
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Location:
Melbourne
Registered:
November 2003
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Re: 2T Piston Identification
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Fri, 30 April 2004 05:24
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Turns out the piston is aftermarket (of course) and given the lack of popularity of this product they don't make off-size rings for this motor any more.
So now I'm getting the piston ring grooves re-machined to the larger size. More money spent I didn't have in the first place
Cheers,
Dan
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