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Post by OBR on Dec 12, 2008 18:30:35 GMT -5
Hi guys, am working on rebuilding my super xl and started to put in the wrist pin retaining clip (the one thats just a c-clip) and put it in the wrong side of the piston (stupid i no) so now it is on the opposite of the exhaust port side and this is where the open end of the wrist pin goes. my question is: does it really make a difference? once i thought about it this orientation almost makes more sense than the correct way because the open end has a flatter sharper edge to come into contact with the retaining clip and the other retaining clip is wider, giving it more surface area to come into contact with the beveled, closed end of the wrist pin. Should I leave it, spend a half hour swearing at it to remove it, or what. Thanks fellas.
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Post by OBR on Dec 13, 2008 17:29:12 GMT -5
I take it no one else has done this...HAHA Well, I think I'm going to put it together as is and go for it. I forsee no reason that my retaining clip orientation should not work perfectly fine. But would still love to hear anyones opinion before I finish up. Thanks again guys.
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Post by mikevan on Dec 13, 2008 18:09:59 GMT -5
Learn something everyday - I never would have thought of this, in fact I didn't when I put the piston back in my 113. I think it's the same way I took it out, but now I'm not sure?
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Post by OBR on Dec 13, 2008 22:42:37 GMT -5
mike, i wouldnt normally have thought of this but the old piston was sitting right next to the saw as i was working on it, of course i didnt think to double check to make sure i put the right clip in the right side until AFTER i put it in  but like i said in my last post, after thinking about it for 24 hrs i decided in wasnt worth taking out. i figured the manufacturers would probably use two plain old c-clips, but you have to be able to take one out easily to get the pin out. so then i got to thinking, why should it matter which side the one you can take out be on, they both do the same job (hold the pin in) just on opposite sides, so if i flip-flop whats the big deal. Anyway, got the old beast back together and boy has she got compression! need to pick up a fuel line and we'll be off and running. |
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Post by MCS on Dec 13, 2008 23:22:13 GMT -5
Well, according to the Homelite service manual, you are only supposed to remove the intake side snap ring and then drive the pin out that side. ;D When reassembling, be sure to install the closed end of the piston pin toward the exhaust side.  It doesn't say why  Now, should you loose sleep over this? How many SXL, or XL12 are assembled incorrectly and are still running? But it does make me wonder if there is a good reason for this. |
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Post by OBR on Dec 13, 2008 23:37:17 GMT -5
the pin is in correctly...only now you would remove the exhaust side clip and drive out in the opposite direction, which i dont think will ever be a problem. I too have wondered the purpose for pin orientation, it kind of makes sense though i guess, you wouldnt want carbon or other exhaust junk getting into the pin...and i would assume the idea behind drilling out the pin is to reduce reciprocating mass, which is logical.
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Post by MCS on Dec 14, 2008 8:38:06 GMT -5
Here is my 5 cents (inflation) on the hollow wrist pin. In a four stroke engine, the pin can be completely hollow for weight reduction but in a two stroke, the intake side and the exhaust side can't have a connection because the intake charge could pass directly to the exhaust or the other way around, the exhaust could affect the intake. Having the closed end on the exhaust side would prevent carbon build up inside the pin.
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