ZoboHerald@aol.com wrote:
>
>
> I'd first replied to Dave that: "TRF came up with one match [out of two].
> According to [their online catalog], 207045 is a "Piston, Bare" and is no
> longer stocked. I'm not sure what a bare piston is, except that perhaps it
> was supplied without rings? Still leaves me wondering about the other five
> pistons, though...."
>
> But then I remembered that I had an early GT6 engine -- KC4213E -- with the
> head off, all stuffed in the barn.Sure enough, I hit paydirt (well, actually
> I scraped dirt off the tops of a couple pistons). This was a very low mileage
> engine out of a wreck many, many years ago. But I digress. Pistons 1 & 6
> carried the Stanpart logo and the number 207045. One had below it "R6" and
> the other "R8" -- for whatever that's worth.
>
> So perhaps the 214947 pistons in cylinders 1-5 are original "Pistons, Bare"
> used in the factory assembly of that later engine, and the 207045 came out of
> a dealer's stock to replace a problem piston in cylinder 6? What's confusing
> is that part numbers in the factory Spare Parts Catalogues appear to be for a
> "piston assembly" (p/n 139809 for early GT6 engines and 149976 for later
> engines) that presumably includes rings and the wrist pin w/clips, whereas
> the Stanpart number on the top of the piston is literally the (unlisted) part
> number for just the cast piston itself.
Last night, I didn't even think to look at the ones that came out of my GT6+.
I'm reasonably certain this engine was
original, based on the mileage and the amount of wear. These pistons have no
number at all on the crown--just the grade
letter (in this case, "G"). However, cast into the inside skirt near the pin
bore is the number 214947.... Still doesn't
explain 207045, but just about confirms that the 214947 is the base piston for
that engine.
As for the description of a bare piston, it's hard to say what the factory
considered it to be, since it isn't described in
the parts manual. For most manufacturers, a bare piston is with the pin and
without rings, since pistons with floating pins
have to be sized to the pin for proper clearance.
As for Dave's most recent email, saying that pistons 1-5 must be original,
because they are numbered one through five in the
"proper place," this is, rather, a clear indication that the engine was
probably completely disassembled at one time, or was
marked by a mechanic in preparation for disassembly. This is not factory
practice. The only need of the factory for any
marking on the piston is the grade stamp, which indicates to the assembler the
optimum piston for a particular bore size.
Numbering upon disassembly is simply good practice after parts have worn in
together.
Cheers.
--
Michael D. Porter
Roswell, NM (yes, _that_ Roswell)
[mailto:mporter@zianet.com]
Don't let people drive you crazy when you know it's within walking distance.
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