help on engine noise

[thom13]

I have had all chains and top and bottom tensinors replaced with noise still persistant,strip down again told a chain had stretched and rebuilt. Noise still there.VVT disconected so its not that,so what are the chances its a lazy tappet as I can't think of anything other than that. XK8 60,000mls

[jagtech]

Coiuld possibly be from rear of engine possibly gearbox/torque converter or drive plate i am a jag tech and would happily take a look my number is 07988 613963 i live in swindon

[thom13]

Many thanks for the interest in my problem, more info for you is,noise only happens on hot starts and will go away when engine is reved up a bit .sounds like a chain on a bike moving up a gear. But as I said all tenseners and chains changed,can I get lazy tappets checked by using a set of feeler gauges

[Brakebuster]

there are two possible causes of noise that you describe, ( but may be others )

one, is the fuel injectors ticking away, the older they get, the louder they can become, and if you have reduced other noises from the work you have carried out, this may be more noticeable

the second could be the VVT valves if fitted, only 4 ltr cars have them, and only on the AJ27 engine , these also become noisy with age

BB

[thom13]

VVT disconnected and noise still there, this noise only occurs when engine is restarted and still warm. All indications look to chains or tensiners but as stated,all changed and checked,I have changed to a thicker grade oil to see if this makes a differance and if so,can it be hydrolic tappetes..

[Nik]

VVT disconnected and noise still there, this noise only occurs when engine is restarted and still warm. All indications look to chains or tensiners but as stated,all changed and checked,I have changed to a thicker grade oil to see if this makes a differance and if so,can it be hydrolic tappetes..

Hi Thom ,
Ever since I purchased my 99MY XK8 I have had an identical sound , only happens once on startup and when first revved , I too have had tensioners changed for the latest all metal type ( the MK2 tensioners fitted incidently were perfect) mine has a full main agent service history and is personally looked after by the workshop foreman .
Mine is due for a service in just over a week , will ask him to listen to mine and give a opinion , mine has made the noise now for 30,000 plus miles , don't think it's serious ,

Will report back ,

Nik

[thom13]

Many many thanks,I feel all I have been doing is giving money away for nothing to this jag enineer,who seems to be at a loss.the last thing I wan't is to keep throwing money at guess work..

[painter]

I have experienced a similar noise on my 96 XK8, and although thought to be VVT, it seems more likely to be a dry chain rattle due to starting up on a slight incline (facing up hill). Since parking with bonnet facing downhill it has stopped. Gradient is about 5 degrees. Hope it is as simple as this.

[thom13]

Problem with engine being noisy was, 1998-1999 engine vvt valves rattle because..explained as follows.
Wear on the big end shells causes loss of pressure to vvts thus the rattle untill thay prime,no noise on cold starts as oil is thicker when cold.
The fix is to do the shells and as the engine has to come out, then replace the rings re'grind the crankshaft too.
basiclly recon the engine to safe future problems and prolong engine life.
I travelled from Glasgow down to Sittingbourne in Kent to see this guy,who was old school jag mec that we don't see now.
Phone call to see what parts I required,and to ask what my problem was,then a phone call to make sure I arrived ok,and a tour of the work shop and my problem explained at a work bench with a stripped down engine.This lad arrived at this garage at seven o clock in the morning to meet me on a "Saterday"
If you require work to your Jag and live anywhere in the south go and see this guy....Tel: 0161 442 1994 Mobile:07876 440450 Email: MAIL@ELITE-JAG.COM Jaguar Specialists Parts Unit 2 Castle Road Business Precinct Castle Road Sittingbourne

[bt965]

I know it,s a long time since this thread started but I,m posting info that I hope will be useful for future reference.
I too had exactly this "tappet" noise problem on my old XK8 that I sold to a lady friend, she rang me last week and I could hear the rattle in the background as she spoke , anyway when I went to look at car I too thought it was tensioner problem, on left bank.
The tensioners were changed and on initial start up the engine sounded sweet ,even though the original ones looked ok, then the rattle started to come back,quiet at first then getting progressivley louder. so the primaries were checked,could find no problems with these either so the engine was put back together. Started and the rattle was still there! So i started probing with the long screwdriver stethascope, turns out to be power steering pump causing expensive noise. changed and all ok.
Learned a few lessons from this-
1 Noises dont always come from where they "look" to be coming from!

2 Have a open mind, its too easy to point to tensioner problems, ( mainly due to the amount of discussion on the subject, and the catastrophic and costly result of failure!)

3 Get help to put ancillary drive belt on!!

Regards Bob

[mike020150]

Thanks for the 'expensive' lesson. The point is well made. Diagnosing noises is nearly always a nightmare, especially so now that cars are increasingly complicated. It's one of the prices we pay for demanding better performance than Austin 7s (or SS Swallows) could provide! Mike.