Hey, all youse guys..thanks for the replies! While some disparage
Summit, I used them as reference because they sell a lot of aftermarket
maker's parts. I surfed for piston wrist pins and wrist pins and found
tons of them in all shapes and sizes. I did find a couple made by Ross
that were side by side comparable, just different diameters. The price
was exactly the same. Naturally the slightly smaller diameter is a tad
lighter, not enough to make a difference in my opinion. Big was 96
grams, smaller was 94 grams.
I will say that the notion of the 0.927 RM diameter being most prevalent
is true. By a long way. Still, every maker does have the Ford diameter
and they run at virtually the same price. So I don't think
availability is the full reason. And the pins no matter the diameter
come in an almost bewildering array of lengths and materials and
retention methods.
I asked the original question, not because I have rods with the ford pin
diameter and whether or not I should go to the larger ones, but because
I have a set of rods that have that diameter off the shelf. Since they
came that way, I was curious as to why since ford pistons come with teh
0.912 diameter o begin with. I suppose the very small difference in
load bearing area in the aluminum piston might be a reason, but, I
dunno. Since I need to have the pistons custom made anyway, I will just
have them made to fit the 0.927 diameter and will also have the pison
maker supply the pins as well. That way, they should fit and I know the
retaining system will work.
Happy Turkey Day!
mayf
______________________________
drmayf
Worlds Fastest Sunbeam, period.
204.913 mph flying mile
210.779 mph exit speed
On 11/23/2011 9:35 AM, Larry Mayfield wrote:
> Ford uses a wrist pin diameter of 0.912 inches for the little end of the
> rod/piston. GM has a wrist pin diameter of 0.927 inches. I see a number
> of Ford products whether pistons or rods offered with the option of
> using the GM wrist pin diameter. I don't know if the Ford pin diameter
> is offered as an option for GM stuff though. Don't care, lol...
>
> What's up with that? Is the GM pin lighter even though it is larger in
> diameter? Stronger for sure but is that the reason?
>
> So, the dumb question is: "why switch from 0.912 to 0.927 inch diameter
> wrist pins?
>
> Keep it technical please...
>
> mayf
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