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Tapping Noise At Idle

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#16 merther

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Posted 03 June 2024 - 01:43 PM

Hi there, in the process of sorting out another head for a swap later when complete.

My latest theory is either a valve seat is on the move when at idle but not when at speed, or the valve guides were not reamed after install and is causing a valve to stick and not close fully.

It seems to be only happening at a certain rev figure. When I turn the motor by hand to set the tappets, all is fine. At idle the noise is present and when driving down the road at 40km or more it's fine.

As above, when I watch the rockers at idle with the cover off, I can see two valves periodically not return to their fully closed positions, giving a big gap between the valve and rocker causing the noise. Valve seat or sticking stem??

Compressions are really good at cranking speed which may support the sticking valve stem theory...

Can't get hold of a bore scope to have a look, so will swap the head when I have one ready.

 Did you find out anymore about your problem? Im having a similar noise..


Edited by merther, 03 June 2024 - 01:43 PM.


#17 merther

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Posted 03 June 2024 - 06:52 PM

With the engine ticking over should I be able to see the push rods rotate? And If so does that confirm the cam followers are turning too?

Edited by merther, 03 June 2024 - 07:08 PM.


#18 PoolGuy

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Posted 03 June 2024 - 06:57 PM

With the engine ticking over should I be able to see the push roads rotate? And If so does that confirm the cam followers are turning too?

That's correct, a dob of paint on them helps you see them spinning.



#19 merther

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Posted 03 June 2024 - 07:09 PM


With the engine ticking over should I be able to see the push roads rotate? And If so does that confirm the cam followers are turning too?

That's correct, a dob of paint on them helps you see them spinning.

Thankyou

#20 Sterling M

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Posted 19 November 2024 - 04:40 AM

Well the saga continues but with some updates.

I bought a endoscope to inspect the valve seats for any movement, all looked ok.

I have just swapped the head for another spare unit and blow me down if the noise is still there!

Inspected the old head and all looked as it should be, so all good.

I removed a restricting plug from the oil way in the block that feeds the rocker gear while I had the head off, just in case it was starving of oil, no change.

My last idea is that there could be something going on with the rockers.

When I rebuilt the motor, I replaced the rocker shaft and also re-faced the rocker ends where they contact the valve stems. I am wondering if I have upset the angle these meet the valve stems and are causing the the rockers to rock against the shaft and posts when they push the valve open,,,just a thought as I'm really running out of ideas.



#21 Shooter63

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Posted 19 November 2024 - 06:35 AM

There has been a couple of people with the same problem posting on various social media platforms recently, both ended up ripping the engine a part, in both cases the lifters/followers were absolutely knackered, as in the sides worn through. In both cases they were using Valvoline R20W50.

Shooter

#22 PoolGuy

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Posted 19 November 2024 - 07:29 AM

There has been a couple of people with the same problem posting on various social media platforms recently, both ended up ripping the engine a part, in both cases the lifters/followers were absolutely knackered, as in the sides worn through. In both cases they were using Valvoline R20W50.

Shooter

A series engines? Got any links so I can see a cam follower with ‘the sides worn through’? Thought not.


Edited by PoolGuy, 20 November 2024 - 08:43 PM.


#23 Sterling M

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Posted 19 November 2024 - 07:49 AM

There has been a couple of people with the same problem posting on various social media platforms recently, both ended up ripping the engine a part, in both cases the lifters/followers were absolutely knackered, as in the sides worn through. In both cases they were using Valvoline R20W50.

Shooter

I've been using Penrite HPR30 which is a high zinc 20-50 oil. Not using anything between oil changes,,,

The reason I've been concentrating on areas away from the cam/followers is that when I listen for the noise with a stethoscope, there is no appreciable noise in that area or around the timing chain/cover area. But it is present around the rocker shaft/rocker's area.


Edited by Sterling M, 19 November 2024 - 04:06 PM.






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