My s2 developed a bad missfire and a loud tapping coming from the 3rd cylinder a while back, since then Ive given the car a full service including plugs and leads etc but it continued, so, I decided to checked the tappets and cam. The exhaust tappet on the 3rd cylinder had a dished base instead of a nice flat one and after pulling the cam out, the lobe for this tappet was badly scored and worn.

I replaced the cam with a newman one and new hydraulic followers, applied plenty of lube and spun the cam once fitted to checked it moved freely and all the valves opened and closed with no probs. All fine there.

Bolted it all back together, fired it up to run it in and the loud tapping from the 3rd cylinder is still there!!! So turned it off to prevent any damage to the cam.

Im guessing my next step is to pull the head off to check the valve to see if its bent at all.

Would you do the same? Or have you got any other suggestions before I pull the head off?

Cheers