Servicing/troubleshooting tappets

[kronik]

Hi All, thought I'd put a post in here, I tried to piggy back a post that was similar in the Speed 6 forum but didn't get much response.

I got a ticking noise in the engine area a 1/4 mile before I got home last time I drove the car. It increased as the engine revs increased. It wasn't long after I'd driven her pretty hard on the A34. Based on the stuff I've read it seems likely (hopefully) that it's a slipped shim or similar - although please let me know if anyone has experience of similar sympton with a different root cause.

I've got the cam cover off and had a look around but can't spot anything just lying around in there. I have absolutely no idea what I'm looking at in there, nor what I should be looking for.

Can anyone give me a guide on assessing what the problem is, where I should be looking if something's happened to one of the shims, where I would even see the shim in it's proper place?

Whilst I'm in there I figured I should check the clearances anyway and address where necessary. Would also like a guide on this!

Treat me as completely stupid for this one, I really have no idea what I'm looking at in there so the simpler/more detailed the explanation the better. Pictures would be a great help but not essential - and of course, to anyone that can take the time to help, I'm very grateful!

[ronspeedsix]

As above you can see the cam lobe facing up. Between the cam and the valve spring you can see the tappet. Push the tappet aside (not possible with all tappets). When the tappet is aside you can see the shim that is lying in the upper side of the spring. Check if the shim is in. Sometimes at high revs you loose a shim.
Shims can be easy taken out when the tappet is aside. I use a magnet.
When a shim is missing, be sure that you find it !!! Otherwise you can damage your whole engine.

Clearance is measured between tappet and shim with cam-lobe facing upwards.
Not all tappets can be pushed aside because there is no room. In that case you will have to press the valvespring with something iron down to reach the shim.
Measure clearance, take out shim, measure shim thickness en then calculate which shim thickness you need for the right clearance.

Ronald.

[Basil Brush]

I put a link to a pic on the "is this going to be expensive" thread in the S6 forum. Make sure the 10mm dia round shims are in place on top of all the valves and look for any scoring or marking on the cam lobes, ie the oval section parts of the 2 cams that push on the valves.

10 thou is about a quarter of a mm, so the gaps we are talking about are v. small - you'll need a set of feeler gauges to check.

[kronik]

Hi all, Ronspeedsix - thank you, I've now been able to check them all, appreciate your detailed explanation.

Basil Brush - saw your pic in the other forum but still didn't clear up the shim thing, I was expecting a piece a few thou deep and that shim looked big - now I understand that there is an initial depth to the shim and the difference is madde up with the size of shim...

So reading left to right as front to back my measurements were:

7 8 6 4 4 5 6 4 5 5 3

9 11 12 11 11 12 13 13 11 11 11

I also looked at the top of the shim on each but am not seeing a groove as detailed on one of the other forums as the root cause. I didn't do the back two as I read somewhere that these are rarely done even by the pros for a service - correct me on this if I'm wrong!

So it doesn't seem like there's any of them massively out, I guess the biggest worry would be the 8 on inlet 2 (I presume a smaller gap isn't going to be responsible for the noise I'm getting?) but should I now assume it's something more serious?

Can anyone suggest any other home diagnostics I can try? OR is it time to give one of the garages a call? I need a service anyway but am a bit skint at the moment, The garage most local to me quoted £1,150 for the service, I just haven't got that kind of cash spare at the moment. did I read somewhere that there's a garage up north that will collect for the cost of their diesel and do the service for a decent price? , expected it to be around £650. If anyone is reading and knows this place then let me know, otherwise I can go back through the forums and see if I can find this info again.

[Basil Brush]

TBH Ron's post was a lot more helpful than mine anyway.

Have you not checked the back 2 then? I think when people talk about these not being routinely done I take it that they are more likely to be left if only a few thou out, rather than not being checked at all.

[lerd]

Give Jason at str8ightsix a call .