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Just watching wheeler dealers on Quest. They are doing a Austin Healey 3000 Mk3. Very nice. Ant just made a comment about not setting the tappet gap to 12thou at the moment as this needs to be done hot?? Is this right? I thought you set them when the cold and this gap was the amount that closed up as the engine warmed up. 

       I've set my tappet gap when cold, is this right for a Triumph or do I need a bigger gap, set them when the engine is hot? 

Neil

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I expect it depends on what the manual says. For TRs it is cold but those who know more than me say it doesn't matter.

What does matter is knowing if you have a higher lift cam. Using the standard gap with a high lift cam can damage the followers or cam as the load is to high. On one of my cars I know it has a higher lift cam although I haven't measured it. I set the tappets to 15 thou just in case.

Edited by John McCormack
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Thanks Guys, 

   I had never heard of setting tappets hot before. I have this tappet sound at tick over ~750rpm, it goes if the revs increase and certainly not present underload (not small end). It comes from around the middle of the rocker cover. 

    I'll rechecked the tappets and they are good. I've read a few different things suggesting an exhaust leak can sound the same but I cannot find one. On searching the forum I found something suggesting it could be wear in the rocker shaft itself. Any views on this. 

Neil

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14 hours ago, NCS_TR3A said:

Thanks Guys, 

   I had never heard of setting tappets hot before. I have this tappet sound at tick over ~750rpm, it goes if the revs increase and certainly not present underload (not small end). It comes from around the middle of the rocker cover. 

    I'll rechecked the tappets and they are good. I've read a few different things suggesting an exhaust leak can sound the same but I cannot find one. On searching the forum I found something suggesting it could be wear in the rocker shaft itself. Any views on this. 

Neil

Yes it could be rocker shaft wear, it could also be the rocker face is pitted and when you set the gap correctly the actual gap between where the valve impacts the rocker is larger, causing the tapping.

I put a new rocker shaft in my daily driver some years ago but failed to have the rockers ground smooth. I sometimes have a 'tapping' noise and believe that is why. 

I go faster and can't hear it.

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17 hours ago, John McCormack said:

Yes it could be rocker shaft wear, it could also be the rocker face is pitted and when you set the gap correctly the actual gap between where the valve impacts the rocker is larger, causing the tapping.

I put a new rocker shaft in my daily driver some years ago but failed to have the rockers ground smooth. I sometimes have a 'tapping' noise and believe that is why. 

I go faster and can't hear it.

Thanks John, 

   Yes presently I'm ignoring it as it goes as soon as any increase in revs or driving. You do have to be listening for it also. When you say grind the rockers smooth, would this be possible just using a file and then wet and dry or do they need to be hardened on something after getting the face smooth. 

Neil

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Hi Neil,

The wear spot on the rocker arm may not actually be wear but where the valve stem has pushed the hardened surface into the softer parent material.

I don't think a file will do much good.  The Wet&Dry may do the job but stop rubbing when nearly flush.

Or you could simply tighten down the tappet adjuster and then slacken off 90 degrees. This will give apprx 0.010"

It is also possible that the tappet noise at tick over could also be a wr=orn cam/cam follower. 

 

Roger

 

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1 hour ago, RogerH said:

Hi Neil,

The wear spot on the rocker arm may not actually be wear but where the valve stem has pushed the hardened surface into the softer parent material.

I don't think a file will do much good.  The Wet&Dry may do the job but stop rubbing when nearly flush.

Or you could simply tighten down the tappet adjuster and then slacken off 90 degrees. This will give apprx 0.010"

It is also possible that the tappet noise at tick over could also be a wr=orn cam/cam follower. 

 

Roger

 

Or a loose cup in one end of the tubular push rod.

Peter W

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