valve clearance sequence
Discussion
I may be running the risk of sounding a bit dense, but I don`t quite grasp what is meant when reading about adjusting the valve clearances in the `bible`.
To adjust the clearance on no;1 cylinder, no;5 will be on `overlap`,and overlap is described as both rockers or pushrods moving in opposite directions.
So I may be wrong but both rockers on 5 cannot move at same timeas valves would hit?
I assume that if the inlet or exhaust valve on 5 is on the move, then one of these at no;1 cylinder is doing the same, hence overlapping, and the stationary vale on no;1 as then adjusted?
Confused, I am. it will probably all come to light when I do the job and actually see the valves turning over, but I like to try and suss the job out before I start.
I don`t want to sound a total plank but a few pointers would be helpfull.
To adjust the clearance on no;1 cylinder, no;5 will be on `overlap`,and overlap is described as both rockers or pushrods moving in opposite directions.
So I may be wrong but both rockers on 5 cannot move at same timeas valves would hit?
I assume that if the inlet or exhaust valve on 5 is on the move, then one of these at no;1 cylinder is doing the same, hence overlapping, and the stationary vale on no;1 as then adjusted?
Confused, I am. it will probably all come to light when I do the job and actually see the valves turning over, but I like to try and suss the job out before I start.
I don`t want to sound a total plank but a few pointers would be helpfull.
overlap is the point where the the inlet valve rocker comes right up and the exhaust rocker just starts to go down. At Top Dead Centre, no.5 rockers should just be at this point, both rockers are ballanced. As the "bible " says, moving the crank pulley wheel to and fro slightly should show this ballance point.
Hope this makes sence. Both valves on No.1 cylinder should now have gaps to adjust
>> Edited by TOPTON on Wednesday 19th January 19:33
Hope this makes sence. Both valves on No.1 cylinder should now have gaps to adjust >> Edited by TOPTON on Wednesday 19th January 19:33
It's important to adjust the clearance while the valves are completely closed. If you adjust them while either valve is on the ramp just starting to open or just finishing closing, then you will set the clearance too high. The easiest way to be sure that both valves are closed is to set them while the piston is at top dead center on the power stroke.
The point of the instructions is to help you work out when this is. It is not straight forward to find because it is a point where nothing much is happening. The easiest thing to find is tdc on the exhaust stroke, because at this point the exhaust valve is closing and the inlet valve is opening. You can recognise this without knowing which valve is which and what way the engine rotates, so it is a good foolpoof thing to find. Having found tdc on the exhaust stroke you turn the crank another 360 degrees which takes you tdc on the power stroke which is what you want. This involves a lot of turning the engine over and you will get tired of it.
There's a smarter way of doing it, which is what Steve's book describes. Knowing the firing order of the engine, having found one cylinder at tdc on the exhaust stroke you can predict which other cylinder is at tdc on the power stroke and so ready to have its valves set.
It may help visualize what is going on to look into the four stroke combustion cycle, I'm sure a quick google would throw up an animated explanation.
The point of the instructions is to help you work out when this is. It is not straight forward to find because it is a point where nothing much is happening. The easiest thing to find is tdc on the exhaust stroke, because at this point the exhaust valve is closing and the inlet valve is opening. You can recognise this without knowing which valve is which and what way the engine rotates, so it is a good foolpoof thing to find. Having found tdc on the exhaust stroke you turn the crank another 360 degrees which takes you tdc on the power stroke which is what you want. This involves a lot of turning the engine over and you will get tired of it.
There's a smarter way of doing it, which is what Steve's book describes. Knowing the firing order of the engine, having found one cylinder at tdc on the exhaust stroke you can predict which other cylinder is at tdc on the power stroke and so ready to have its valves set.
It may help visualize what is going on to look into the four stroke combustion cycle, I'm sure a quick google would throw up an animated explanation.
... being very very careful that the screw driver doesn't jam as the piston comes up and knacker the plug threads. Better to use something a little more forgiving.
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