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Floyd · 10-16-2020, 04:39 PM

Pdstark asks a real question. A valve, either intake or exhaust, will open because the cam shaft is going to push it up with solid force. The valve has no choice in this part of the operation. However when it comes time to close, only the spring force is involved in this action. Therefore if the valve is not moving freely in the guide, it may stick and close slowly or not close all the way. Now we have a situation of a valve that is slightly open at the wrong time. rough running, backfire , popping in exhaust can all happen depending on which valve is misbehaving . Many times it is intermittent ( always the most fun problem to chase down) and clear up depending on running conditions.
I will leave the discussion to those who have lots of experience in sticking valves, their symptoms and analysis.

10-16-2020, 04:39 PM	#48
Floyd Senior Member Join Date: May 2010 Posts: 468	Re: Marvel Classic Motor Oil Pdstark asks a real question. A valve, either intake or exhaust, will open because the cam shaft is going to push it up with solid force. The valve has no choice in this part of the operation. However when it comes time to close, only the spring force is involved in this action. Therefore if the valve is not moving freely in the guide, it may stick and close slowly or not close all the way. Now we have a situation of a valve that is slightly open at the wrong time. rough running, backfire , popping in exhaust can all happen depending on which valve is misbehaving . Many times it is intermittent ( always the most fun problem to chase down) and clear up depending on running conditions. I will leave the discussion to those who have lots of experience in sticking valves, their symptoms and analysis.