coldbear 29 #1 Posted May 9, 2015 Hello Fellas.....I just purchased a 1989 520 H with close to 800 hrs. on her. I bought her cheap enough that I can afford to rebuild her right. She needs one piston, a rod, and a cam. My question is there anyone that knows how to read these Onans? I've overhauled several Rotax sno engines in my times but this Onan is a strange bird to me. I live around the Cincinnati area and can travel to a reliable machine shop that can bore and R@R new the valve/valve guides. Any suggestions as who would be a good rebuilder ? Share this post Link to post Share on other sites
boomers_influence 106 #2 Posted May 9, 2015 cold with only 800 hrs SHE should not need a rebuild. i stock any and all parts that you will need for this repair. many of my customers do it themselves. please have cast # from the rod side beam, and inside of the piston. also the spec# and S.N. boomers_influence@yahoo.com 651 437 2826 M-F 10-7 S-S 12-6 cent time zone. thank you. boomer ( the used onan engine parts guy, also NOS and new ) Share this post Link to post Share on other sites
coldbear 29 #3 Posted May 10, 2015 (edited) Thanks Boomer for I haven't the vaguest idea how to fix this mess. The internal damage was severe enough to break the cam , one connecting rod, one piston, and nipped the bottom of one cylinder, and nick one throw of the crankshaft. The seller said it still run after this influx but I seriously doubt that. Yes sir, see if you can locate of few internals for me. I always wanted one of these models but now , I don't know. Oh by the way...we used to make the trip up there for the Fall MSA sno-show. I've been by your house many times and never knew it.lol. Edited May 10, 2015 by coldbear Share this post Link to post Share on other sites
cleat 4,990 #4 Posted May 10, 2015 No engine is safe if run low on oil. I have seen Kohler, Briggs, Tecumseh, Pontiac, Chev etc all throw rods. Fix it properly and maintain it and you will be good to go. Cleat Share this post Link to post Share on other sites
coldbear 29 #5 Posted May 10, 2015 I just bought this wrecked 520, Cleat. Believe me, there is no one on this Red Forum that takes better care of equipment than myself. I really like things done right. THE FIRST TIME ! Share this post Link to post Share on other sites
bmsgaffer 2,043 #6 Posted May 12, 2015 Coldbear: I live in Cincy. Check with Monarch Automotive Machine Shop. (859) 283-9099 They are located in Burlington, KY off of Rt 18 and Limaburg Rd. (They are 'round the back of the Mikes Automotive building) I just had them rebuild a Kohler for me and I know they had mentioned they were working on an Onan. I think they did a fine job, haven't gotten the motor up and running but it looks nice and they were somewhat reasonably priced. I just had a few nit picky issues (they machined the bore without having the new piston first, not a HUGE deal, but not ideal). So just talk to them a lot about what they are doing. Let me know if they will do it or if you find anyone else around that will. I always like to have a list of people to call. Oh and you will probably want to replace both pistons and rods at the same time just to be sure everything is balanced. Share this post Link to post Share on other sites
geod919 12 #7 Posted May 12, 2015 I too, can recommend Monarch, I work at KOI in Newport and since closing our machine shop this year, we've been referring everyone there. Call me if you need any belts spark plugs or bulbs or batteries! 1 Share this post Link to post Share on other sites
bmsgaffer 2,043 #8 Posted May 12, 2015 I too, can recommend Monarch, I work at KOI in Newport and since closing our machine shop this year, we've been referring everyone there. Call me if you need any belts spark plugs or bulbs or batteries! You are on my list new friend! Share this post Link to post Share on other sites
coldbear 29 #9 Posted May 12, 2015 Thanks for the information. I'll check with Monarch, see how backed up they are. This is race season around here. Shops get covered up with work. Once again thanks. bad. Share this post Link to post Share on other sites
coldbear 29 #10 Posted May 13, 2015 Checked with Monarch. They are three weeks behind,reporting down one man. I'll keep them in my prayers. Share this post Link to post Share on other sites
bmsgaffer 2,043 #11 Posted May 13, 2015 Three weeks behind or three weeks out? I dropped off my K341 and didnt see it again for like 3 months (and I wasnt in a hurry). So three weeks either way ain't bad. Share this post Link to post Share on other sites
coldbear 29 #12 Posted May 13, 2015 I need the valve seats ground and the valves turned. If I had the machine I'd do it myself. At times, machinist go too far on the grinds. Leave a thin disk for a valve then charge you for it. I think boomer has some parts coming for the rebuild. This should help to get the old 520 back on the grass and the garden. 1 Share this post Link to post Share on other sites
