Engine Rattle

[Equalizer]

Just a quick question, and I have taken on board the warnings regarding timing chains, etc and hope to get an appraisal from XJ Restorations soon but.....

When started from cold there is the merest rattle from the engine. Rev and it goes, drive and it goes. Warm and its not there. When out today and driving at speeds above 60mph, if I lifted my foot off the accelerator, after a could of seconds the rattle can be heard again as the engine drags the speed down. It seems to stop instantly if throttle applied and also stops sub 50mph. At speeds less than 50mph, I found it hard to replicate the noise at all.

Timing?

Valves?

The only thing I thought may have affected it is that I filled her up with 60 litres of 98 RON Super Unleaded Shell V-Max this morning instead of 95 RON standard unleaded...would that have any effect? The owners book says safe to use either, so not sure.

[PaulGover]

A rattle at startup usually means timing chain tensioner's gone. Unless you have evidence it's recently been replaced, get it changed to the latest metal ones as a matter of urgency.

The petrol change would at most have reduced pinking noises.

[Equalizer]

Damn.

That's the second diagnosis of tensioners and reading symptoms elsewhere has now got me very concerned.......

I will ring around tomorrow, but does anyone have any kind of idea about the ball park cost of replacement? Its not something I would consider doing myself. Finding lots of information online about the problem but very little in the way of costs and garages that specialise in the marque I would have thought by now would have a fairly fixed price for this work....?