Tappet/timing chain noise

[RobertGrieve]

Hi all,

Having had the cylinder head shimmed I have since been driving for 50 miles or so and am noticing an improvment in tappet noise but it is still not as quiet as I expect it should be. The noise seems to be intermittent depending on rpm, and i would say is quieter when engine warm.

The noise I think it coming from the front left so exhaust side. I expect one of two things at present, the 1st or 2nd from front followers are badly shimmed or the timing chain adjuster needs tightening and the noise I’m hearing is potentially the chain slack.

I had a peak inside the cam cover and found some scoring on the top of the 2nd from front follower, il take the cover off for a better look but wanted to share the photo here in case anyone has seen similar. To me it looks quite bad, and I worry about the route cause. Wondering if oil starvation at that lobe could do such a thing.

[christopher storey]

That scuffing looks very peculiar to me : when I magnified the pic it became clear that there are several overlapping marks, each having a half ( or more accurately two-thirds) moon shape . I have never seen anything quite like that, and I wonder whether a foreign object has been involved. Either way, I think that cam follower needs changing. I should also like to know whether the follower is rotating or not : although they are not designed off-centre so that they rotate positively, I would have thought that a follower jammed rotationally in its guide is undesirable, but it may be rotating because to my eye there is a suggestion of circumferential scoring on the follower which again, to me, is odd

Good luck with it

[RobertGrieve]

Hi chris,

Yes you are quite right on the shape, il take the cam cover off for a better shot. It’s like the lobe has been striking the follower at a partial angle.

The follower rotates freely and I cannot feel any play side to side. I also cannot see any evidence of marks on the guide or the lobe.

I think i will clean the area from oil, check for foreign material as you suggest and crank the engine to watch for oil supply and also check the torque of the cam bearings.

Wondering if the head got too hot whether it is possible the follower could seize in the guide and therefore create too much of a residance against the cam leading to severely increased wear?

[RobertGrieve]

Had a better look at this today. I have replaced the follower for a new one. The one that came out was the long skirt type, which annoyingly means going down the route of refitting all long skirt type followers (which I read can be good at quietening the tappet noise) is probably not worth doing. The old follower was definitely visibly worn and you could see evidence of the barrel shaping taking place although I must invest in a digital micrometer to measure properly.

Anyhow- it is quieter, il run it for a while and see what it’s like.

Perhaps the head will come off again and il have new guides and oversize followers fitted, but until then... il leave as is

Robert