BryanRTenn 11 #1 Posted January 8, 2015 I have a P216 that was running strong, I thought, I can't imagine how strong it would run if both pistons were actually rotating lol!!! This is the first Onan I have ever had torn completely down. I have pulled a service manual & talked to a couple people who have worked on many of them but I always like different takes on situations & I trust the members here to shoot straight & have the on-hands knowledge. First off, what in these engines is the main reasons or things to look for that would cause rod failure? Rod broke close to the piston, in the thinnest part I guess, enough to where all of it fell to the sump & was up in the bore enough to where the crank could continue rotating & didnt mess the journal up all that bad from what I can see. I've had a few briggs cap bolts work loose & cause problems but both nuts are securely on both rod bolts. I know the crank gear is on there good, has to be pulled with 10-32 hardened screws. One guy told me its best to heat the gear a little, pull it, & when putting it back on it MUST be heated to over 450 degrees & put on quickly to "sweat" it on there??? I'm not one to argue with someone who has been there done that several times just wondering if this sounds like SOP. He said when heated to 450+ it will slide on like butter but when it cools just a little you're stuck. Also, I'm assuming the cam has to come out to get the crank gear off? The cam & gear are made together as an assembly? To get the cam out do the valves have to come out? What special tools or tricks is there to getting the valves and/or camshaft out? I need to order a rod for sure, mine is #170-3439. I know 18 & 20HP have a different stroke, is that because the rod is different or the throw of the crank? Is there any other rods that work, does it have to be a 3439 & does any other engines use that rod? Any help and tips would be greatly appreciated. I'm not a novice to engines by any means, just never been in one of these Bryan Share this post Link to post Share on other sites
BryanRTenn 11 #2 Posted January 8, 2015 I just re-read through the service manual, it doesnt seem too in depth, but then again maybe im overthinking it. It says just pull the crank gear, nothing about heating or having to pull the cam. It does say to remove valves to remove cam, but not to remove cam & gear to remove crank gear. Share this post Link to post Share on other sites
BryanRTenn 11 #3 Posted January 8, 2015 been reading this thread over on MTF http://www.mytractorforum.com/showthread.php?t=91204 he knows his stuff it sounds like. He says you dont have to remove cam to remove crank gear, crank gear may come off easy or may have to use impact, & you DO have to heat it to put it on Share this post Link to post Share on other sites
sorekiwi 761 #4 Posted January 8, 2015 That thread on MTF is pretty good. The crank gear is on there pretty tight. I made an adaptor and used a harmonic balancer puller to pull it off. No heat to pull it off, but I did heat it to put it back on. I dont remember if the gear is on a taper or whether it is just on there tight. I think the manual and the MTF thread should answer most of your questions. I do remember being impressed with the engine when I got inside it. A nicely designed piece. Share this post Link to post Share on other sites
BryanRTenn 11 #5 Posted January 8, 2015 your puller looks like a great idea, pulling with the big bolts Share this post Link to post Share on other sites
boomers_influence 106 #6 Posted January 8, 2015 bryan please call on this, and i will walk you through it. 651 437 2826 cent time zone. thank you boomer ( the used onan engine parts guy ) 3 Share this post Link to post Share on other sites