608KEB 796 #1 Posted July 5, 2015 (edited) I want to adjust the valves on my 520H. When checking gauge 5000ths intake and 13000ths exhaust. Is this correct? Do I check the clearance by when the black nut is about to spin against the rod? What do I use to clean the top of the piston and cylinder head? Is there anything else that I need to do since it's apart? I cleaned the carburetor. Edited July 5, 2015 by 608KEB Share this post Link to post Share on other sites
JAinVA 4,636 #2 Posted July 5, 2015 Oven cleaner works good to clean heads.I have used Super Clean purple with good results as well.Not sure about the piston tops other than light scraping. Luck.JAinVA 1 Share this post Link to post Share on other sites
Kurt-NEPA 755 #3 Posted July 5, 2015 I just adjusted the valves on my 520H. .005" and .013" is correct. There is a adjustment procedure in the Onan manual, but I usually just rotate the engine until the valve is closed. Then watch the lifter until it is fully retracted. Then I adjust the intake tappet until the the .005" feeler enters and the .006" does not. I rotate the engine and check it several times. Repeat with .013"/.014" feelers on the exhaust tappet. I would love to do this with the engine running like I would do on a car, but you can't do that on this engine.For cleaning the head, I use Carb and Choke cleaner with a plastic or brass brush. It cuts most of the residue. I polish things with a ro-loc scotch brite pad in a die grinder. Just don't get carried away. No sharp steel tools. 1 Share this post Link to post Share on other sites
boovuc 1,090 #4 Posted July 5, 2015 For both questions, Kurt does what I do! Share this post Link to post Share on other sites
608KEB 796 #5 Posted July 5, 2015 I rotated flywheel to top dead center. Both valves are closed. I can't fit feeler gauge between tapet and rod. So I'm guessing it is to tight. Share this post Link to post Share on other sites
608KEB 796 #6 Posted July 5, 2015 Cleaned up well with Easy Off. Share this post Link to post Share on other sites
608KEB 796 #8 Posted July 5, 2015 How many pounds of torque? For the head? Is there a order Or pattern that I tighten the bolts at? Share this post Link to post Share on other sites
Kurt-NEPA 755 #9 Posted July 5, 2015 14-16 ft-lbs for the graphite based gaskets. There probably is a preferred pattern for tightening, but I just criss-cross. Tighten snug, then half tight, then to 14-16 ft-lb. I usually double check to make sure. 1 Share this post Link to post Share on other sites
JAinVA 4,636 #10 Posted July 5, 2015 Onan manual calls for the head bolt to be torqued 5ft/lbs,10ft/lbs and final torque of 14ft/lbs.The sequence is the center pair first,next upper pair ,then the pair below the center pair.The upper single goes next then the bottom pair.Luck,JAinVA 1 Share this post Link to post Share on other sites
608KEB 796 #11 Posted July 5, 2015 Thanks I checked the torque as I took them off. It was 10lbs-26lbs.. Thanx!! Share this post Link to post Share on other sites
boomers_influence 106 #12 Posted July 5, 2015 club and 608i would like to ask all of you withan onan twin cylinder to join theyahoo onan club. ( google it )just say you want to join tolearn how to work on your onan engine.the site has the P series parts and service manuals,as well as most of the other twin cylinder engines.then you can learn how to do it correctly. ( set valves, and torque )thank you. boomer ( the used onan engine parts guy,also NOS and new ) 3 Share this post Link to post Share on other sites
Kurt-NEPA 755 #13 Posted July 5, 2015 Hey Boomer, Thanks for the invite. I just sent a "join" request. I'm always looking to learn more. Share this post Link to post Share on other sites
WNYPCRepair 1,923 #14 Posted July 5, 2015 I did too, but satisfying Yahoo's password complexity was a challenge. it rejected some very good ones, but the one that finally passed was nowhere near as secure, in my opinion. Share this post Link to post Share on other sites
