First of all, thank you for the add. I am freshening up my 49SP and my 52E. Both well maintained and well kept saws. My question is two fold..I know that the pistons for these saws are interchangeable but is there any advantage in putting a 52 piston in a 49 or vise versa. Second, should the wrist pin be a slip fit. I assume so but upon removal of pins in both saws the pins wear very snug (not slip fit) Any thoughts? Thanks in advance for your responses.
49SP/52E Piston question
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No real advantage to swapping them. The 49 piston is single ring and lighter so it will rev quicker due to less friction and weight. The 52 piston is twin ring and has a wider wristpin bearing and thrust washers so it is heavier. Generally the 52 piston is considered heavier duty to run in a pro series saw and will take more wear and tear. Wrist pins are generally a light press fit. If you take a heat gun to the piston for a minute or so they generally slide right out
Thank you. Best leave it alone. Good to know about the wrist pin. I haven’t encountered a slight press fit before in any saws that I have had apart. I am happy that this is normal. Thanks again for the good info.
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One other thing to remember is that when you reinstall the wristpin cir-clips, position the gap at 12:00 or 6:00 and that they are throughly seated in the grooves. Good luck!
Good info. Interesting little tidbit on the wrist pin subject, I acquired the 52E sometime in the mid 90’s. I have run the saw regularly since then. When i tore it down one circlip was missing. Wrist pin was centered with no indication of it ever moving, Bore and piston are virtually spotless, hence the original question of the snug pin fit. Guess i should go buy a lottery ticket.One other thing to remember is that when you reinstall the wristpin cir-clips, position the gap at 12:00 or 6:00 and that they are throughly seated in the grooves. Good luck!
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Wow!! Usually when a clip comes out it does major damage!!! The gap positioning advice is meant to combat the loss of a clip. Perhaps it was reassembled at some point without the clip......anyway you are indeed very lucky......I'd buy two lottery tickets!!! Look the muffler over to see if the clip made it out to the space before the baffle.
It wasn’t in the muffler. I guess the snug pin fit saved the day. Always something new. I am a retired Heavy equip mech, have seen some wild things over the years but missing wrist pin retainers weren’t one of them. Agreed, can’t believe this didn’t result in a major crash a long time ago.
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You might also check down in the lower end around/behind and between the counter weights and the main bearings with a good light. It could not have gotten out past the baffle in a stock 49/52 muffler so I'd check really carefully that lower end. Another place to check is the upper transfers in the cly.....could have got wedged up in there too. These are fairly fine wire so could have found a temporary home somewhere in there. The tightness of the wristpin in the piston might have been enough to keep it in place. Though it's a tight fit at room temp once the piston heats up in use that changes. If you can't find hide nor hair of it anywhere you are certainlly lucky!!
