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Engine basics => Engine set up tips => Topic started by: Motorman on July 31, 2018, 10:17:59 PM
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I bought an OEM piston and ring for my ST46 for when it eventually wears out. I noticed the ring does not fit in the groove of the piston. Did SuperTiger leave the ring a little thick so you could fit them yourself because, I think that's awesome that back in the day they thought the average modeler had the skill to lap a ring.
No they didn't, at least not intentionally. Also, I rarely saw to individual engines that were exactly the same.
The original version of the engine had a different liner (thicker, as I recall, but I could be wrong). I am definitely not sure that there weren't some other differences, like the ring thickness. Randy probably knows.
Brett
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Id get the michealometer out .
The Irvine 40 ring in the K&B , you have to hold your mouth right ; Dosnt seem to fit , but it does . Revolves Free once fitted .
Im Figureing the TWO S T Part Numbers are for TWO Ring Specs .Earlyer for Chome Bore ( maybe harder ? )
LATER for the softer Un Chromed Bore . ! ??
Actually Chromed Rings ( or is it chrome molly rings ) in old iron Norton Bores , are a relevent concept , perhaps .
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The DEBURRING Trip , removing all sharp edges - cept maybe the top outer on ring - would ease the fitting .
DOES IT ENTER EDGEWAYS FROM ADJACENT , I.E. will the outer edge locate in the outer edge of the land . Sorta figure * like . ! ? ?
Fit in a used pistons likely superior . Take up the slack . ;D
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I bought an OEM piston and ring for my ST46 for when it eventually wears out. I noticed the ring does not fit in the groove of the piston. Did SuperTiger leave the ring a little thick so you could fit them yourself because, I think that's awesome that back in the day they thought the average modeler had the skill to lap a ring.
NO all the ST rings are fit and go into the piston groove, that said there are 2 different thickness rings for the 46, and the 60 for that matter
I think the 2 sizes are 40 thou and thinner one for double ring, The single ring is thicker than the double ring piston, I have also seen damaged pistons that the ring will not fit in
I have done many hundreds of ST 46s, the ring should fit, but not be tight, and should spin easy. IT also should not be loose where it moves up or down in the groove
By the way ,The ST 60 ring is 48 thou thick for single and 39 for double
Randy
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is yours a single ring piston ?
Randy
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try to put the ring in backwards, just the outer edge, then go around the ring groove in the piston to see if the groove is the same all the way around, I have found many are not, and will either stick, or not seat properly
Randy
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I bought an OEM piston and ring for my ST46 for when it eventually wears out. I noticed the ring does not fit in the groove of the piston. Did SuperTiger leave the ring a little thick so you could fit them yourself because, I think that's awesome that back in the day they thought the average modeler had the skill to lap a ring.
I just opened several packs, and the G21 46 ring is just a tad over .040 thou thick, for the single ring piston
Randy