Hi guys,

I took the rocker cover off today as I have been hearing a knocking noise on stopping and a tapping noise whilst running and I can safely assume the valves haven't been locked at for a good 15k miles, seperate to my valve clearances (which were all out of spec apart from 1) - the cam chain seemed to be extremely tight, I decided to slacken it off and let the spring re-extend the piston and I could watch the slack while it happens. I slackened it off and let go however the piston did not re-extend, I checked the tension on the cam chain and it was loose. I took the tensioner out and installed a spare I have, same deal, infact when I put the spare tensioner in it pushed against something inside the engine (even with the spring all the way back), and when I let the spring go, still nothing. However, if I turn the tensioner the other way wjhilst installed, it will tighten the cam chain as I watch it. Both of the tensioner work as expected outside of the engine (preload the spring, let it go, and the piston extends) It's like they don't have enough force to push against whatever it is they do inside the engine unless I manually adjust it

This cannot be right? If I just installed the tensioner and let the spring go, currently the cam chain would be completely slack, which surely would not end well. I can tension it up myself, but I don't know how much I should be doing so. What's going on there? Any help appreciated!

Getting my valve shims tomorrow hopefully, so want to be happy with the cam chain before I put it back together and fire it up :S

Cheers guys

I picked up my new shims yesterday, going to put it all back together later, so any suggestions welcome.

Is it something silly like, the tensioner doesn't work properly unless the rocker cover is installed? What I don't want to do is tension it up manually with the cover off, put the cover back on and it be too tight and eat itself... Likewise, I don't want to leave it loose, put the cover on and the tensioner not tension back up and then be loose and eat itself!

Basically, with the cover off, should the automatic tensioner be able to extend itself and tension the chain visibly with the cover off? Or is the tension with the cover off the same with the cover on? In which case I can just do it manually for now.

Cheers

The tensioner is pretty strong.  When you reinstall it, you usually have to compress it completely by turning the screw in the middle.  It will lock when fully compressed.  Once installed, you have to unscrew it again to unlock it.  Once you get past the unlock point (like half a turn) it should extend out automatically and reapply tension.  This behavior is true whether it's installed in the head or not.

If you take the tensioner out, does it extend all the way by itself?

Thanks for the reply, yeah when out of the engine it works as expected, I screw it all the way back and let it go and the piston shoots out. But when I put it into the engine, it does nothing unless I manually 'unscrew' it, and I can see the cam chain tighten up.

I have two tensioners, as my original one started leaking oil, and I replaced it with a brand new one about 2 months ago. In that case, I just let it go into the engine, and clearly it was fine as the engine ran for the last 2 months. I didn't have the valve cover off then however, which I do now. Both tensioners work fine out of the engine but will only extend by unscrewing manually while inside.

I was trying to figure, perhaps they will only extend automatically with the valve cover on (being tensioned somehow), or should I be able to see it happen with the valve cover off? It seems like it's meeting too much resistance inside the engine for the spring to work unless it's done manually. What is it that it presses against, and can I check that somehow?

You can look at the parts fiche.  There's a long curved track that it pushes against that pushes against the chain

Hi guys,

Sorted the valves out today, when it came to retensioning the CCT for whatever reason, it's working perfectly as expected today. I even swapped around the tensioners to make sure it wasn't that, and they both worked as expected. Not sure what changed today to yesterday, but I'm damn glad about it anyway.

Thanks for the suggestions tho.

Oh, and the valve work went great - engine sounding and pulling great