Keith 21 #1 Posted March 6, 2020 (edited) I broke a head bolt on my Onan P220G - on the 520H. Are new head bolts available? Can studs be used? Tim Edited March 6, 2020 by Keith wrong engine Share this post Link to post Share on other sites
Macgyver 109 #2 Posted March 6, 2020 The original bolts were grade 8. If you can find grade 8 thread rod then yes you can change to studs. Or just go to a hardware store and get new bolts but either way reuse the washers that were on the. Original bolt. A little trick I figured out when putting the heads back on torque them up in steps. First in the range of 6 to 8 foot pounds then up to 12. At that point I let them set several hours or overnight then finish torquing to 16 ft pounds Share this post Link to post Share on other sites
Keith 21 #3 Posted March 8, 2020 On 3/6/2020 at 9:11 AM, Macgyver said: The original bolts were grade 8. If you can find grade 8 thread rod then yes you can change to studs. Or just go to a hardware store and get new bolts but either way reuse the washers that were on the. Original bolt. A little trick I figured out when putting the heads back on torque them up in steps. First in the range of 6 to 8 foot pounds then up to 12. At that point I let them set several hours or overnight then finish torquing to 16 ft pounds. Thanks. Its good to clean the head and valves once every couple years. I figure a switch to studs might be a good idea. One of the bolts broke with about 3/8 inch exposed. I want to weld a nut to the broken bolt to extract it. Tim Share this post Link to post Share on other sites
Keith 21 #4 Posted April 23, 2020 What are the thread specs? I'd like to clean the holes. Share this post Link to post Share on other sites
Keith 21 #5 Posted April 24, 2020 20 hours ago, Keith said: What are the thread specs? I'd like to clean the holes. They are 5/16-inch 18 threads Share this post Link to post Share on other sites
