Hi,

HELP!
My XK8 has jsut developed a tapping noise from top end, left bank I think.
Quite a loud tapping noise, which disappears when revved. only started 2 days ago.

Worth pointing out that someone (previous owner) put a new engine in this car 16K miles ago - but they fitted a XKR engine in it without the superchargers, hence the heads do not have VVT. yet still the tapping

Here's a youtube link -
Any advice welcome,
Thanks Tony.

 

I'd get the cam cover off pdq and see what's amiss, it sounds worryingly like tensioner failure. Certainly do not run the engine again until you have sorted it or it can be mega bill time.

 

...and when MCW739 says mega-bill, in my neck of the woods, a tensioner destroyed engine replacement is in the neighborhood of $7,000 to $9,000....


DO NOT RUN THE ENGINE, TAKE OFF THE VALVE COVERS AND CHECK THE TENSIONERS

 

I would not run that baby. If you can look at the timing chain tensioners or get it to a shop.

 

Thanks for the help guys!

Car parked up until I get time t look at it. Is it advisable to change the chain as well or just the tensioners?

Will it be both tensioners or just the upper (secondary) ones?

 

Just the secondary tensioners. The chains should be okay unless one of the plastic shoes is missing and the chain is worn.

Of course, it's better to change everything, but that's a much bigger project, and the primary tensioners aren't exposed to as much heat.

 

Hi,

Thanks, you guys were spot on.

See photos of removed tensioner, has a crack in the side wall.
and the top appears to be just metal, should it have a plastic top on it

Tensioner came out easy, without the need to remove the exhaust sprocket???
Primary chain is still nice n tight

upper Chain looks OK, or should it be replaced anyway if plastic shim has been missing - only done about 20 miles since noise detected.

Tony.

 

Congrats!

The missing plastic slipper is in your oil pan. Keep an eye out for oil pressure issues that might indicate a clogged pick up screen. So far I have not had to remove the pan on my car but those that have do not seem to have too much trouble with it.

Unless you can detect damage to the chain I would leave it.

 

+1 on the chain. One of my slippers was missing but the chain looked okay, so I left it alone. I did, however, remove the pan and cleaned the pickup screen.

 

Job Done
Two new tensioners and new upper chains fitted!
The chains showed significant wear to the inner edge - so I though it best to change - both tensioners were split (and of different types).
Engine purring nicely now with no strange noises.

Thanks to all for your help and advice.

PS - following my failure to remove the Crankshaft pulley (well stuck on, bent /destroyed two pullers), I developed a new method of removing the upper chains - by removing both cam gears the whole assembly pulls away from the cam sufficiently enough to replace the chain, just had to make sure I kept tension on the main timing chain so it didn't move from tensioners/guides etc.
It is a shame - cos I did want to check the lower chains and tensioners.
Guess you must need some very specialised / heavy duty pullers for this pulley????

 

I just had the chains and tensioners changed on our car. The mechanic, who has experience with both the xk100 and the xk150, said it took him 1 1/2 hours to get the crank pulley off. I'm glad now that I didn't take it on myself as I had been intending to as I have a feeling that would have stopped me. 2 of the primary chain guides were cracked and one of the aluminium secondary tensioners had failed, so I reckon the job was done just in time.