Getting the last 'good days' of driving in for 2014!

Found a break in the weather few days ago so took the jag out for a blast. Probably cursing myself by saying my car has not let me down in ages (apart from MPG!) it's had the usual coil pack and exhaust manifold issues in the past, so the only job planned for the near future is the top tensioner. (Slight rattle on a cold startup). Has anyone found the need to replace chains/guides etc, or should I just try the tensioner for now?

 

Nice Xjr! mine is british green. I been thinking about mine as well, currently when i cold start i hear this grind but after few second its gone. so im not sure if its the tensioner? how does your sound? is it only when you first start the car?

 

Mine is definitely the tensioner. Must be losing to much pressure when it's left to cool. Mine rattles for a few secs when cold then goes away. Been like that for a while now and I was wondering is there any instances of a complete failure, ie eating its own chain and valve/piston damage?💩

 

By coincidence, the timing tensioner has come back onto my radar screen in the last week or so, albeit in a good way for a change!
I too have been down the well charted path with timing chain rattle on startup from cold, and started by replacing the upper tensioner. My car already had the later type fitted, and I replaced like for like, to precisely no effect. There was still a momentary rattle when starting from overnight cold.
I them summoned up the courage to remove the timing cover, and replace the lower tensioner, guides, and the chains. Not a 5 minute job, no signs of abnormal wear, and again, absolutely no difference. I tried a thinner oil, thinking it would circulate more quickly, absolutely no difference.
Over the last couple of weeks, overnight temperatures have finally dropped to more seasonal levels, and slightly counter-intuitively, the startup rattle on the cold morning seems to have disappeared, prompting the following homespun theory:
The lower tensioner is pressurised by the pulsing of the timing chain itself, the movement of the piston drawing oil in through a non return valve from a small reservoir drip fed from within the timing cover. When the engine stops, the tensioner cylinder remains pressurised, but with the passage of time, the pressure dissipates, most likely through the one way valve, or perhaps the piston seal if the tensioner is worn. In my case, this always took 12+ hours to reach the point where the chain momentarily rattled on startup again. The fact that the problem seems to have gone away (temporarily I suspect) with the advent of cold overnight temperatures makes me think that the gradual leakage of oil pressure has been stemmed by the oil becoming colder and hence thicker. As I say, a homespun theory, and quite possibly wrong. In any event, having replaced the wearing parts, and in the absence of any apparent history of these chains giving serious problems, I am resolved to live with the momentary rattle on the first start of the day, and enjoy the wonderful smoothness for the rest of the time.

 

I see, that actually helps, i think it is normal to hear a grind when cold start, maybe its the oil not reaching the chain at first. I have seen a xj8 with tensioner problem and it sounds very obviously 。

 

Here is a Word paper on that task that I wrote when I messed with mine a loooong tine ago,

Hope it clears teh mud somewhat.

There is a thread elsewhere in here titled "So the uodate tensioners also fail............" or similar, that has HEAPS of info in it also.

AJ16 Top Timing Chain Tentioner Fiasco.doc