EA82T piston skirt differences

[steptoe]

pics no worky , tba

okay, technical issue and time - sorry

here it is now, hoping for a certain member to come in and tell what he knows about different stuff of these EA82T pistons,
seeing as though he was the one that asked elsewhere - short or long skirt pistons ?

The short skirt shiny piston is never (yet) used after market by TIK
The longer skirt is std size with 19 in casting in four places, and a B stamped in top of piston
have read that A B and C pistons are to cater for minor machining tolerances of maybe 1 thou differences of the bores ?


pic above ^^ short skirt has more cylindrical shape of piston below gudgeon pin


pic above ^^ see the short skirt under the long skirt, short is wider






pic above is side on, rings off, was EA82T S for spider, unsure of originality over the years

[nncoolg]

I have found a few different variants of OE EA82T pistons;
A long skirt with a single set of valve reliefs type,
A long skirt with a double set of valve reliefs type,
a Short Skirt with offset piston pin (L & R specific) type

The Long skirts have nice built-in piston slap reduction while they're in good condition, but all the ones I have found so far have a full length oil ring slot which has the tendency to flex and crack the pistons and cause that good old EA82 piston knock and blow-by we are all too familiar with

The Short skirts are much stronger built with basically the same casting as the NA pistons. They have a nice strong rib running around under the piston pin and a few holes drilled behind the oil rings, instead of a big square slot. They do however need to be fitted in the correct side of the block as the pin is offset to combat the short-skirt slap. I have tried to identify these pistons to order some but I cannot find a part number for them. 2 Dealers have tried as well.

please see pictures below:

[steptoe]

argh, cripes...my new pistons are like the short skirts in many ways, same looking oil holes instead of the long arse, piston weakening oil slots - so may be posible that they are also offset and need to be determined before allocating to a particular pot prior to machining !

I should get the engine number from the block. The new short skirts do not share that machined down circular section in the centre of the crown of your genuine short skirt piston. AB marking may be a B piston tolerance for A side block ?

Jeepers, Neville, how did you measure the offset gudgeon pin centre or can you tell by lookin' at it ?

Hmm, would be best measured before I ripped the rings off, but noticing this piston - also from #4 - the top ring has a gap of 10mm, lower 13mm though more finger slicing pretzel bending was required to remove the blighter. Of the oil rings, the top one has a smaller 2mm gap than the lower ones 3 mm gap.
I'll be measuring the next lot before they come off

The scary view of a piston not being as solid as one thought ....