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Old pistons

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  • Old pistons

    im tearing an engine down, and it has ford .045" pistons with center lock wrist question is regarding the rings. The upper slot has a .012" spacer so it can use the same size ring as the middle slot. Yes, different size slots. The middle has one inch pieces stacked underneath the ring, so as to push the ring tighter to the cylinder wall. Whether these were originally one solid ring, or maybe they broke into pieces over the years, I don't know. Anyone have info to shed some light on this?

  • #2
    .045" is an odd size by today's standards. A new set of pistons and rings would be the way I'd go. That way you'll have a round cylinder without taper and ridge.
    Run it by a machine shop and see if .060" would work OK.


    • #3
      That is the other thing. #4 has a large ridge on ONE side. Like something is cocked or miss bored. Possibly stuck rings?Wrist pins are all centered on connecting rods. Problem started when he changed oil and used detergent. Started smokin and knockin. I haven't got that far, but am thinking sludge in an oil passage to center main. Some of the rings are fairly stuck. Still wondering what the deal is with the two different spacers????


      • #4
        Spacers are used when the ring lands are worn, but the owner doesn't want to buy new pistons. The ring grooves can be cut wider, then a spacer installed to take up the gap. I did a set for a customer many years ago, but for the price of Model A pistons, I'd just buy a new set. You need to bore the block anyway to get rid of that ridge.


        • #5
          In the old days we use to cut the top ring groove wider because they were wore. then we used a spacer to take up the clearance. The spacer should be on the bottom of the ring. If you have a big ridge at the top of the cylinder, it is time to bore for bigger pistons.


          • #6
            Thanks for the explanation, that makes sense. I guess labor was cheaper the parts back then.


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