zanepetty 117 #1 Posted December 24, 2014 One of my freinds thought he would help me by putting my ring compressor on today. He put the bottom of the piston in a vice with no protection. The vice left a scratch/gouge mark on the piston below the rings. Is that going to call for a new piston? Please help. Thanks so much. Zane Share this post Link to post Share on other sites
Firpo701 407 #2 Posted December 24, 2014 Yeesh! The politically correct thing to do, as most here will tell you, would be to replace the piston. I, however, understand how tight money can be most of the time, so, here is my suggestion. First thing to do would be to examine that piston skirt very, very close, to make sure there are no hairline cracks from the pressure of the vice. I would use a magnifying glass under well lit conditions. If it appears to check out, and you say it is below the ring grooves, take a file and "lightly" smooth down any burrs left from the vice marks. Use a piece of 220 sandpaper, afterward, on the area, to better smooth out the aluminum where it has been filed. You certainly don't want to score the cylinder bore. Main thing is to make sure that piston isn't cracked! If it is, and it comes apart, that would make for a bad day! If there is the slightest doubt about that, I would replace the piston. 2 Share this post Link to post Share on other sites
rmaynard 16,344 #3 Posted December 24, 2014 Dittos on the "yeesh". Obviously your friend has no idea what he is doing and should be kept away from helping in the future. You are lucky that the damage is below the rings. From the bottom ring down, there shouldn't be a compression or combustion issue. What Firpo said about hairline cracks is what concerns me. You can always file and buff out any small surface damage, but if the vise was tightened enough to keep the piston from moving, you could have an egg-shaped piston, and microscopic hairline cracks. Personally, I would check the piston with a micrometer for out-of-round. If it is, ditch it and ask your friend to chip in to help you buy another one. 2 Share this post Link to post Share on other sites
zanepetty 117 #4 Posted December 24, 2014 (edited) That sounds like a good idea guys. I appreciate that. I'll probably just go ahead and try to find another one. Is the 4107405 the one I need? I'm looking at the ones on eBay if that helps. I know there are two different bores and the info I've googled is kind of unclear Edited December 24, 2014 by zanepetty Share this post Link to post Share on other sites
Mr. 856 170 #5 Posted December 25, 2014 piston+vise=disaster I'm still trying to figure out why the vise came into the equation? 1 Share this post Link to post Share on other sites
zanepetty 117 #6 Posted December 25, 2014 My friend tried to help me. He thinks he knows everything. I told him he ruined it and he thought it was ok Share this post Link to post Share on other sites
zanepetty 117 #7 Posted December 25, 2014 Is 4187405 the 2 15/16 piston? I've tried to look it up but I'm not 100% sure Share this post Link to post Share on other sites
rmaynard 16,344 #8 Posted December 25, 2014 Kohler 4187405, 41-874-05, 4187405-s are all variations of the same number for a 2-15/16" or 2.938" STD piston for K-161 and K-181 Share this post Link to post Share on other sites
zanepetty 117 #9 Posted December 25, 2014 Oh good. Thanks. That's what I thought but it would be my luck to order the wrong thing. Share this post Link to post Share on other sites
Lagersolut 743 #10 Posted December 26, 2014 I think it was a wise decision to order a new one, if the old one flew apart in your bore, all your hard work and money would be down the drain. After reading what the other guys posted there's no way I would have chanced it. Share this post Link to post Share on other sites
BradyS 6 #11 Posted December 27, 2014 Send him a bill. Cub Cadet 1200 Cub Cadet 109 Cub Cadet 149 Cub Cadet "O" Cub Cadet SO76 Plenty of attatchments to put them to work. Currently looking for an RJ35, if you know where I can find one let me know. Share this post Link to post Share on other sites
