artbuc Posted March 10, 2008 Share Posted March 10, 2008 RE: FSM RM626U2, Vol 2, pg EM-61 What is the purpose of the exhaust camshaft gear spring and sub-gear? When replacing timing belt I rotated LH exhaust camshaft backwards a few times (counterclockwise). Now I have high compression on the LH side at 230 +/- 5 psi. RH side compression is perfect at 220 +/- 5 psi. I'm thinking the reverse rotation screwed up the exhaust camshaft sub-gear causing the LH side exhaust valves to be closing too soon. Thanks for any help I can get. Quote Link to comment Share on other sites More sharing options...
artbuc Posted March 31, 2008 Author Share Posted March 31, 2008 RE: FSM RM626U2, Vol 2, pg EM-61What is the purpose of the exhaust camshaft gear spring and sub-gear? When replacing timing belt I rotated LH exhaust camshaft backwards a few times (counterclockwise). Now I have high compression on the LH side at 230 +/- 5 psi. RH side compression is perfect at 220 +/- 5 psi. I'm thinking the reverse rotation screwed up the exhaust camshaft sub-gear causing the LH side exhaust valves to be closing too soon. Thanks for any help I can get. I found the answer. The sub-gear aka scissors gear is the part of the helical drive gear which is spring loaded to hold it against the driven gear (on the intake camshaft). The sub-gear minimizes noise due to gear lash. You can not damage the helical camshaft gears by rotating them backwards. Helical gears are designed to operate in either direction. My compression measurements are meaningless because I did the check on a cold engine. Well, not completely meaningless in that it shows I am a nitwit! Quote Link to comment Share on other sites More sharing options...
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