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[Healeys] Fwd: Loud Metallic Click

Subject: [Healeys] Fwd: Loud Metallic Click
From: austin.healey at gmail.com (Chris Dimmock)
Date: Sun, 29 May 2011 23:40:23 +1000
References: <57A84B1C-F8A6-48AB-87E4-C1366B36D77A@gmail.com>
> Ha.
> And that's the difference Patrick!
> It was a tinkeling sound rather than a clicking sound!
> If you'd kept driving, like Wally gates did, or like Steve Byers  
> did, or i did with a Sprite (many years ago), you would have just  
> had a shrapnel dented cylinder head roof and piston!!
> Here is the problem......
> The top ring wears through the alloy piston, and the ring gap is  
> worn and increased. The ring "flutters" in the worn ring groove. The  
> ring breaks, and starts to erode the ring lands above and below, due  
> to increased tolerances.  The ring land above and below it is then  
> eroded to the point of failure. The alloy ring land is no match for  
> the fluttering steel ring.
> Then a chunk of the top (crown) alloy ring land parts company from  
> the piston crown.
> Followed by the broken piece of steel ring.
> Then the clinking starts. The piece of steel ring bouncing around in  
> the combustion chamber.
> Until it exits via the exhaust valve with an obvious clinking. And  
> you hear it all the way down the exhaust system!.
> You just didn't drive it long enough for the clinking!!!!
> What does the top of your combustion chamber/ piston look like???
> Like its been Shot blasted with a square section piston ring??
> At least you know what the noise was Patrick. I still think the  
> other issues will be cam followers/ cam and little ends.
> This issue seems to occur only on cars fitted with new rings fitted  
> to old pistons, when the pistons probably should have been replaced,  
> rather than re ringing.
> Best
> Chris
PS your top ring will be broken.
> Sent from my iPhone
>
> On 29/05/2011, at 9:12 PM, "Patrick and Caroline Quinn" <p_cquinn at 
> tpg.com.au 
> > wrote:
>
>> G'day
>>
>> Listers would recall the loud and expensive noises coming from the  
>> engine of
>> the BN3/1.
>>
>> The engine is still in the car, but everything hanging off it has  
>> now been
>> removed. Yesterday my eldest son and I removed the cylinder head.  
>> It was a
>> struggle, but once the overdrive throttle switch was removed it was  
>> possible
>> to lift the head, move it sideways and then away from the engine.
>>
>> At first glance everything appeared as it should be, but looking more
>> closely today, a 12mm by 5mm piece from the edge of the crown of  
>> the No 2
>> piston was missing. Small bits of aluminium were embedded in the  
>> top of the
>> piston and minor damage was evident in the combustion chamber. The  
>> top
>> compression ring was intact hence the smooth but noisy running

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