Tapping noise from 3.5 \Rover V8

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anglia215
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Tapping noise from 3.5 \Rover V8

Post by anglia215 »

Hi everyone,
Looking for some suggestions/thoughts on a tapping noise from my V8.
It is quiet and smooth at idle, goes like a train at full throttle, but if you back off the throttle slightly,there is this metallic tapping sound that will disappear if you squeeze the throttle just slightly.
i wondered if i have a lifter pre load issue? (not checked them yet though) Not something i have experienced with one of these engines before, so not sure what it is.I will add, i have noticed i have a little smoke from the left hand bank exhaust, and the tail pipe is a little wet, but i have no noises at idle or at full throttle, and the performance seems to be spot on.
Any ideas, before i start tearing the engine down???

Thanks
Lloyd.



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ChrisJC
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Re: Tapping noise from 3.5 \Rover V8

Post by ChrisJC »

That little bit of smoke might be an imperfect mating of the manifold to the head. Worth getting that sorted before going any further as it will make a noise too.

Chris.
--
Series IIA 4.6 V8
R/R P38 4.6 V8
R/R L405 4.4 SDV8

anglia215
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Re: Tapping noise from 3.5 \Rover V8

Post by anglia215 »

Hi Chris,
thanks for the feedback. Are you referring to inlet or exhaust manifolds here??

Lloyd

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Re: Tapping noise from 3.5 \Rover V8

Post by unstable load »

ChrisJC wrote:
Wed May 29, 2019 5:35 pm
That little bit of smoke might be an imperfect mating of the manifold to the head. Worth getting that sorted before going any further as it will make a noise too.

Chris.
I agree with this.
Have a look at the exhaust manifolds, a leaking exhaust manifold will sound very similar to what you describe.
Cheers,
John

beastanglia
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Re: Tapping noise from 3.5 \Rover V8

Post by beastanglia »

Well, i have finally looked into this issue further, and yes, i did find some exhaust manifold gaskets not sealing correctly, but more disturbing is i seem to have an exhaust valve guide moving. Maybe this is the tapping sound. You can see through the spring that the valve guide is virtually touching the valve spring retainer cap, so much that i can't compress the spring to remove the collets!
Can you get oversized valve guides? i'll obviously have to replace it, once i figure out how to compress the spring and remove the spring and valve.
Any ideas out there??

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ChrisJC
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Re: Tapping noise from 3.5 \Rover V8

Post by ChrisJC »

Surely if the rocker is able to push the valve down, then the guide must be far enough down to allow you to compress the spring and remove the collets? Or are you saying the guide is seized to the valve and is going up and down with the valve? If that's the case, then I think you'll have to grind the valve in half!

Chris.
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Series IIA 4.6 V8
R/R P38 4.6 V8
R/R L405 4.4 SDV8

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Re: Tapping noise from 3.5 \Rover V8

Post by beastanglia »

Found out the valve was stuck in the guide! Cut the valve spring to release the retainer. Luckily, a new guide was a suitable interference fit in the head, so valve and guide are being replaced. Don't know what caused it? all was running fine apart from the occasional ticking noise and a bit of smoke from the exhaust. Did find the rear exhaust manifold gaskets leaking though.

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