AntonUK
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| posted on 4/3/18 at 03:01 PM |
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Zetec Cam Timing
I am just refitting the cam belt after a head change and have come across an issue.
As per the haynes i set the timing positions with crank at TDC and the locking bar in the cams. Loosen tensioner, rotate 2 times and tighten the
tensioner.
But... at one point in the engines rotation a distinct slack in the pulleys appears. It is only in one area of rotation it is tight at every other
point...
What have I missed?
Build Photos Here
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chris
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| posted on 4/3/18 at 03:41 PM |
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do you mean you are rotating the engine with the tensioner loose
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obfripper
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| posted on 4/3/18 at 04:29 PM |
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The tension will dance about with the tensioner bolt slack, it wouldn't be the first time i have seen incorrect instructions in the haynes
manual.
Start with the cam sprocket bolts loose enough to turn the pulleys, the tensioner allen key wound back (iirc clockwise) to the stop and the tensioner
bolt lightly tightened to hold this position while fitting the belt.
Then with the crank timed up on tdc and cams locked with the bar, you need to slacken the tensioner bolt to allow the tensioner spring to operate,
tighten the cam sprockets(while counterholding with special tool) , then tighten tensioner and turn crank over twice to tdc.
Then refit the camshaft bar. If it doesn't fit then slacken the camshaft bolts and repeat the above process until the bar fits
satisfactorily.
Dave
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chris
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| posted on 4/3/18 at 04:41 PM |
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if you are turning the engine over with a slack tensioner then the tight spots are probably the the valves making contact with the pistons
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AntonUK
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| posted on 4/3/18 at 06:01 PM |
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quote:
Originally posted by obfripper
The tension will dance about with the tensioner bolt slack, it wouldn't be the first time i have seen incorrect instructions in the haynes
manual.
Start with the cam sprocket bolts loose enough to turn the pulleys, the tensioner allen key wound back (iirc clockwise) to the stop and the tensioner
bolt lightly tightened to hold this position while fitting the belt.
Then with the crank timed up on tdc and cams locked with the bar, you need to slacken the tensioner bolt to allow the tensioner spring to operate,
tighten the cam sprockets(while counterholding with special tool) , then tighten tensioner and turn crank over twice to tdc.
Then refit the camshaft bar. If it doesn't fit then slacken the camshaft bolts and repeat the above process until the bar fits
satisfactorily.
Dave
Thanks that helped, I took a step back, had a cup of tea and revisited it. Ive managed to sort it now. I needed to undo the inlet sprocket and
re-tighten, in turn it moved the slack to the tensioner.
quote:
Originally posted by chris
if you are turning the engine over with a slack tensioner then the tight spots are probably the the valves making contact with the pistons
I never said the engine was tight?
[Edited on 4/3/18 by AntonUK]
Build Photos Here
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