in reply to Re^3: Organizing and presenting a cross-reference
in thread Organizing and presenting a cross-reference

For example, in the following two lines, only the presence of a part no for the last manufacturer distinguishes them. Doesn't that make the second a duplicate of the first with missing information? Ie. redundant?

Grrr. That's what I was trying to avoid when presenting this data. Remember when I said I'd be trimming off a number of the columns? That's what happened.

A lot of the data is redundant - that's just how it's organized - but not because it's for different vehicles or whatever; it's because whoever put it together didn't use an easier way to say "vendor X's plugs 123,124, and 125 match vendor A's plug 999". Instead, they end up saying 

A    B    C    D    X
999  001  002  003  123
999  001  002  003  124
999  001  002  003  125

[download]

It's dumb, and I know it's one of the things I have to factor out - but I figured that I'd be taking care of lots of redundancy anyway, and this would just get taken care of as part of the parsing process.

My point is, that whilst plugs from different manufacturers may be interchangable for a given vehicle, each manufacturers plugs have different ranges of operating parameters, which means that plugs from two different manufacturers are not interchangable for all applications.

I assure you that this is not the way it works; plugs with different operating parameters get a different part number. The parameter ranges vary widely, but they're standardized - for exactly the reasons you state - and they're comprehensible as data.

I was at an auto parts store two days ago, and had them look up a plug for me - an NGK B7HS-10 - and they pulled up a screen that showed all the equivalents, which exactly matched the list that I had. They never asked me what vehicle I had, and it wouldn't have helped them if they did: it was a Yamaha 15HP outboard motor, and I no auto parts store is going to list that as a vehicle. :)


--
"Language shapes the way we think, and determines what we can think about."
-- B. L. Whorf

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Re^5: Organizing and presenting a cross-reference
by BrowserUk (Patriarch) on Sep 24, 2008 at 14:38 UTC
    I assure you that this is not the way it works;

    Sorry, but this is a subject I know a little about so you'll excuse me if I don't take your word for this. Just because your local autoparts shop has made some attempt at deriving a table of cross-manufacturer equivalences, doesn't mean that they knew what they were doing when the did so. Having been burned (expensively) with just such a "Yeah! That'll do the job" assurance...I'm twice shy!

    plugs with different operating parameters get a different part number.

    Yes, within any given manufacturers range. But, as the presence of two or more 'equivalent' parts within a single manufacturers range testifies, the ranges can overlap. So, for example, you might have: 

    Cylinder Temp: low----A--B-------C-------D-----------high
ManA
  plug1        ********** 
  plug2             **************
ManB
  plug1          *********************
  plug2                   *********************

    [download]

    For a vehicle requiring C, ManA.plug2 and ManB.plug2 are interchangable.

    But using that equivalence to suggest fitting ManA.plug2s to a vehicle D, specified as taking ManB.plug2 could be costly.

    This is why all the manufacturers ask for the application in order to recommend the plugs in their range.

    You might want to read this, paying particular attention to the last paragraphs on pages 2 and 3.

    Examine what is said, not who speaks -- Silence betokens consent -- Love the truth but pardon error.
    "Science is about questioning the status quo. Questioning authority".
    In the absence of evidence, opinion is indistinguishable from prejudice.
[reply]
[d/l]

      [sigh] And this would be the other reason for my not wanting to present this specific data set. I really did not want to get into an argument about the merits of spark plugs, etc. - I just want to know how to organize the data in the way that I stated. I'd appreciate it if you could help me do that; if a bad experience with your local car shop means that you can't do that, well, thanks for your effort so far.


      --
      "Language shapes the way we think, and determines what we can think about."
      -- B. L. Whorf
[reply]

        Your missing the point BrowserUk is making.

        What you have been told by your autoshop is not correct, it may well do for the parts salesman but it is not the correct way to identify the right plug for the job.

        Plugs vary as BrowserUk has said across a spectrum of temperature ranges and individual models of the same car may require different plugs depending on the conditions they are operating in.

        Different manufactures plugs within the same temperature range do not always have the same equivalent across the range. So a NGK plug may have a choice of two plugs in say the Autolite range or vica versa. It all depends on what the plug is fitted to and the conditions it will be used in.

        So you need the fitting details ie Car or boat model year engine size sometimes even a chasis/engine number etc.

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