TC10284 113 #1 Posted June 19, 2022 520H with p220g. Model number 4120oe03. This tractor has 690 hours on it. I have adjusted the front and rear intake and exhaust valves, twice, to manual spec. The rear cylinder only had 60 psi right after I adjusted the valves a 2nd time. The front has around 90. Then after running the engine a couple minutes, I test the rear cylinder compression again and it only has 45psi. Is there anything I can do to help it? Share this post Link to post Share on other sites
8ntruck 7,833 #2 Posted June 19, 2022 Is this a symptom of a loose valve seat? Share this post Link to post Share on other sites
lynnmor 7,815 #3 Posted June 19, 2022 If you are sure that each valve lifter was opposite the cam lobe when you made the adjustments, then pop the heads to see the condition of the engine. A loose valve seat can show low compression, but not in every case. With low compression, the engine will need some degree of disassembly. 1 Share this post Link to post Share on other sites
RED-Z06 2,567 #4 Posted June 26, 2022 Mu p220 showed 120/20..lashed valves..120/80. Ran 45 minutes, 120/20...pulled heads, intake valve seat had nearly ruined the block Share this post Link to post Share on other sites
