[spannerrash]

Hi all

I apologise in advance if this seems a bit of a ramble but I think you'll need all the information in order to help me out.

5 years or so ago I replaced the timing belt, chains and chain tensioners on the car. I used the paint a mark on the chains and cams method, only referring to counting the links to double check my work. All went well and the car has run perfectly for the last 5 years. That said I have only covered approx 3000mls in that time.

A month or so ago I started to notice a missfire at tick over. It wasn't enough to register any faults or even trigger the misfire counters but I could feel it through the seat. She was just more shakey than normal.

My first thought was a vacuum leak but I couldn't find anything. I have previously renewed all the vacuum pipes a couple of years ago.

Now, I'm not one for firing the parts cannon but I have hanging around in my shed a full set of new spark plugs and a full set of oem ignition coils. Being very easy to swap I thought I'd give it a try. I then had another thought. I've never done a compression test on this car so while I had the plugs out I thought I'd give it a go. This is where things got interesting.

Bank 1 was constantly reading 165psi give or take 5psi across all 4 cylinders.

Bank 2 was constantly reading 187psi give or take a couple of psi across all 4 cylinders.

How can this be?

I've probably gone a bit ott with this but because I have the time on my hands I went for it.

I've removed the inlet manifold just incase there was anything going on in there with the variators. The compression this time was slightly lower on both banks. I guess the manifold does have a slight ram air ability.

The timing of the belt is bang on. TDC and the camshaft locking bar fits perfectly.

I'm not even sure at this point that this is the cause of my slight missfire. I guess it could be but I could have just stumbled across something else.

So, leaking valves? I guess I'll have to get hold of a leak down tester but I don't understand why all 4 bank 1 cylinders would be low, unless I have bent valves. There was nothing wrong with the original chain tensioners by the way. I changed them because of the startup rattle but the plastic guides were all intact. So I have no reason to suspect bent valves.

I have used an endoscope to check inside cylinders 1 to 4 and can see no piston or valve damage.

I guess my question is, how possible is it to get the chain timing 1 tooth out, not set any codes and the car seem to run perfectly fine for 3000mls?

I'll sort out a leak down test and let you know how it goes but does anyone have any other ideas?

I've included some pics of the chain tensioner as of today when I took the bank 1 cover off. The engine is set to cylinder 1 TDC.

Thanks Frank