Tappet gaps on v12

[Motionwork]

Hi all,

I thought that I would tune the engine up while waiting for spring to arrive. One of the jobs on the 'to do' list is check the tappet gaps as they sound a bit noisy . I have removed the cam cover and measured the gaps on one side of the V and ten tappet gaps measure 0.009" and two measure 0.010. I am yet to check the other side.

I assume that because they are so close, they have been set at this on purpose. The recommended setting is 0.012 - 0.014. Is there a detrimental or beneficial effect of having smaller gaps than recommended?

I would welcome comments on whether I should leave them as they are, or set them to the recommended gap.

Matthew

Series 3 OTS
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[mgcjag]

Hi Mathew.....firstly i only have a 4.2 so dont know S3 too well u are checking the gaps becaus u think they are a bit noisy....the gaps arnt correct so they need resetting....... however quite often tappet noise is not just down to the gaps but the followere that rattle in the guides...... first i would make sure u have a goog qulity set of feller gauges this could make a difference to your measurements..... also if u re post use the S3 section u may get more input....Regards Steve

[JimmyS]

Hi Matthew,
If the gaps are smaller than recommended, the valves will open earlier than is ideal and will close later. The opposite applies if the gaps are larger, with valves opening late and closing early. Unless you have a non-standard camshaft, I would stick to the manufacturer's recommended clearances.
Regards,
Jim

[Motionwork]

Hi Jim and Steve,

Thanks for your observations regarding the feeler gauge, I'll check it with a micrometer tomorrow to make sure it is accurate.

I am sure it is a standard camshaft, so will re-set the gaps to the manufacturer's recommended clearance.

Regards,
Matthew

P.S. sorry for the duplication on the post, it happened while using the back button on the computer.

[Woolfi]

I had big niose from the tappets 14 years ago. When we measured the gaps, they have been okay. The noise came from wider tappet "cylinders". To reduce this noise, the tappet-cylinders must be bored out and tappets with oversice must be used.
Regards Wolfgang Gatza