Author Topic: tappet rotation  (Read 1088 times)

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Williamsburg

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on: March 31, 2020, 09:37:19 am
Hello Ladies and Gentlemen, could anyone tell me if the tappets rotate only at the point when the piston is at tdc, or should they rotate irrespective of the pistons position, any reply will be greatly appreciated , thanks,
Will


Bilgemaster

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Reply #1 on: March 31, 2020, 12:37:16 pm
Under pressure from the cam followers the pushrods shouldn't rotate easily using one's fingers. If there is any noticeable up or downward movement of the pushrods possible at any point in the piston's travel, then the pushrods(s) need adjustment.

"Hoohoohoblin's" YouTube channel has a fine guide to tappet adjustment for old style Bullets here: https://youtu.be/4bmgJPyCUNU
« Last Edit: March 31, 2020, 01:10:32 pm by Bilgemaster »
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ace.cafe

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Reply #2 on: March 31, 2020, 12:51:22 pm
Hello Ladies and Gentlemen, could anyone tell me if the tappets rotate only at the point when the piston is at tdc, or should they rotate irrespective of the pistons position, any reply will be greatly appreciated , thanks,
Will
For purposes of lash adjustment, the pushrods should only rotate with fingers when engine is at TDC on the compression stroke. This is when both valves are closed, which is the place where adjustment can take place.

At other piston positions, there will be spring pressure on one or both pushrods, and adjustment should not take place at any other position than TDC on compression stroke.
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Seipgam

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Reply #3 on: April 01, 2020, 01:39:26 am
Just to clarify, if it's not clear enough already.

Adjust tappets when engine cool, at TDC with both valves closed.
You should be able to spin the pushrods but not feel any up/down movement when adjusted correctly.

As Ace and Bilgemaster said, when there is pressure on the pushrod you probably won't be able to spin them.

Geoff.
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Williamsburg

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Reply #4 on: April 05, 2020, 07:53:23 pm
Good evening all, just seen the replies, thanks alot, other than mightily relieved,  I've learnt something new. Cheers all and take care