[xj] XJ6 piston id stamp

Hi all, had this question on the ‘engines’ forum for a few
days with no replies so thought with more activity here I
might get an answer.
I have a spare fuel injected series 3 XJ6 4.2 engine which I
have just striped down. The id stamp on the pistons is
EAC2045 with 3 of them having the addition of a much
smaller 1010 stamped after the EAC 2045.
All 6 pistons read 92 mm with the vernier gauge.
Question is what does the 1010 stand for and why only on 3
of the pistons.
I look forward to your replies.
Thanks
Eugene AKA. old jag man.–
old jag man
ARMAGH, United Kingdom
–Posted using Jag-lovers JagFORUM [forums.jag-lovers.org]–

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Eugene,

How do the weights on the pistions compare?

Wondering if three are a different weight and done that way to balance things out?

Joe ATo: xj@jag-lovers.org
Subject: [xj] XJ6 piston id stamp
From: “old jag man” eugene67@hotmail.co.uk
Date sent: Fri, 9 Nov 2012 09:36:03 -0800

Hi all, had this question on the ‘engines’ forum for a few
days with no replies so thought with more activity here I
might get an answer.
I have a spare fuel injected series 3 XJ6 4.2 engine which I
have just striped down. The id stamp on the pistons is
EAC2045 with 3 of them having the addition of a much
smaller 1010 stamped after the EAC 2045.
All 6 pistons read 92 mm with the vernier gauge.
Question is what does the 1010 stand for and why only on 3
of the pistons.
I look forward to your replies.
Thanks
Eugene AKA. old jag man.

old jag man
ARMAGH, United Kingdom

===================================================
The archives and FAQ will answer many queries on the XJ series…
FAQs: http://www.jag-lovers.org/xjlovers/xjfaq/index.html
Archives: http://www.jag-lovers.org/lists/search.html

To remove yourself from this list, go to http://www.jag-lovers.org/cgi-bin/majordomo.

// please trim quoted text to context only

Hi all, had this question on the ‘engines’ forum for a few
days with no replies so thought with more activity here I
might get an answer.
I have a spare fuel injected series 3 XJ6 4.2 engine which I
have just striped down. The id stamp on the pistons is
EAC2045 with 3 of them having the addition of a much
smaller 1010 stamped after the EAC 2045.
All 6 pistons read 92 mm with the vernier gauge.

Question is what does the 1010 stand for and why only on 3
of the pistons.

The manuals are silent on that matter, Eugene…

But there are three grades of pistons, F/G/H relating to bore diameter after
honing - which, when given in inches, differs at the fourth decimal. And
likely to the second decimal in mm - ‘92’ is too crude…:). Actually there
is also a ‘S’ grade - specifying piston-to-bore clearances, likely for some
special needs…

The salient points being that the diameter of the pistons should be measured
at the skirt and compared to bore measured at the bottom of the cylinder -
no wear at these points. The required clearances are given in the manuals -
if you want specifics…:). But also, the bore difference between upstairs
and downstairs, together with any ovality will indicate the degree of
wear…

It is of course vitally important that the pistons go back to the same
bores, and with the original gudgeon pins fitted - gudgeon and pistons are
matched pairs. The connecting rod are numbered, and hopefull in the correct
sequence. But all that depends on what you intend to do with the engine, of
course…

As for your question; the ‘1010’ may refer to something within the above and
is a manufacturers code with unknown meaning. The pistons may be
aftermarket, implying that they were changed at one stage, for whatever
reason - but that is sheer guesswork…:slight_smile:

Frank
xj6 85 Sov Europe (UK/NZ)-----Original Message-----
From: old jag man
Sent: Saturday, November 10, 2012 6:36 AM
To: xj@jag-lovers.org
Subject: [xj] XJ6 piston id stamp

===================================================
The archives and FAQ will answer many queries on the XJ series…
FAQs: http://www.jag-lovers.org/xjlovers/xjfaq/index.html
Archives: http://www.jag-lovers.org/lists/search.html

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In reply to a message from Frank Andersen sent Sat 10 Nov 2012:

Hi Joe and Frank. Thanks for your responses.
Interesting point on the possibility of weights being a factor
re the additional stamping. Shall check it out.
Re this engine Frank it is just a spare. I have no intentions
of having it recon’d. I started dismantling to remove the
cylinder head as I may use it being the injected series 3
type. As for the rest I have found a spot for it to hibernate
until the time comes when I may require a part.
Regards
Eugene.–
The original message included these comments:

It is of course vitally important that the pistons go back to the same
bores, and with the original gudgeon pins fitted - gudgeon and pistons are
matched pairs. The connecting rod are numbered, and hopefull in the correct
sequence. But all that depends on what you intend to do with the engine, of
course…
As for your question; the ‘1010’ may refer to something within the above and
is a manufacturers code with unknown meaning. The pistons may be
aftermarket, implying that they were changed at one stage, for whatever
reason - but that is sheer guesswork…:slight_smile:
Frank
xj6 85 Sov Europe (UK/NZ)


old jag man
ARMAGH, United Kingdom
–Posted using Jag-lovers JagFORUM [forums.jag-lovers.org]–
–Support Jag-lovers - Donate at http://www.jag-lovers.org/donate04.php

===================================================
The archives and FAQ will answer many queries on the XJ series…
FAQs: http://www.jag-lovers.org/xjlovers/xjfaq/index.html
Archives: http://www.jag-lovers.org/lists/search.html

To remove yourself from this list, go to http://www.jag-lovers.org/cgi-bin/majordomo.

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