94 Disco New Engine Noise (With Video)

[wabuson]

94 Disco

3.9L V8

Yesterday it just stopped running whilst in line at a drive thru. The starter cranks and there was fuel pressure in the line. I followed the rave and found weak spark in the plugs so I replaced them all. Now the engine starts but is making this noise. Seems to be coming from the passenger side valve area. Any ideas?

[Marten]

I'm presuming you have double checked plug fitting and ignition timing, HT leads, etc.

Difficult to be sure from the video sound track but you may have a valve timing problem. Remove the rocker cover and check all your tappet clearances carefully. If you have an unusually large clearance at one valve it could just be that the tappet adjuster screw has slacked back. A loose locknut will confirm this. Check the circular caps are in place on top of the valve stems. Also check that all the valve sleeve locating pins are tight (A row of 8 hex headed bolts on the RHS of the engine just below the head gasket). A slack or missing bolt could allow the sleeve to move. Wouldn't directly affect valve timing but might indicate a bigger problem!

Worst case scenario, you need to be absolutely sure you don't have excessive wear of a circular cam shaft follower. There have been several "soft" batches of valve gear for sale in the recent past! Probably not a problem if the "original" set is still fitted. I reconditioned my engine and un-knowingly fitted a "soft" set and it wrote off the crank case after 10k miles! Not a common problem though!

[JimDay]

If it didn't make a noise before fitting the new plugs I would say it's something to do with them are you sure you have fitted the correct plugs , are they all tight & have not cross threaded one (easy to do ) causing compression blow by which will sound like a loud ticking noise do the plugs have sealing washers or are they taper seats I can't remember long time since I worked on a Rover V8 if washer are they all fitted if tapered seat are they all clean (no grit)