XJ6 & XJ12 Series I, II & III 1968-1992

Failing Head Gasket ?

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  #161  
Old 03-18-2016 | 05:55 AM
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Originally Posted by Grant Francis
Maybe the top chain has settled a tad. It can happen.
Hey Clarke and a great job done. Sorry I missed the "blow-by-blow" over the whole journey, but even playing catchup, I wanted to add to Grant's advice - it may prove of benefit to others.

With any of the Jag 6's, especially after a head R&R, it is not "abnormal" to develop a cold start chain rattle after re-torquing head bolts and settling in - and it's odds on that it will be the UPPER t/c tensioner needs adjusting - just as Grant says.

A neat trick is to use your home-made "lug-hole tube" (stethoscope like) that you used to tune multiple SU carbies taped not into but against the edge of the breather access hole - thus keeping you and your fingers well away from the nasty bits!

Two observations are fundamental -
  • Is the pitch/tone of the rattle equal on both engine acceleration (modest) and deceleration? It is important just to "blip" the throttle - then immediately release. Too much will eliminate the rattle. Listen carefully to the rattle pitch. A worn or loose UPPER t/c will tend towards being both quieter and a lower pitch on deceleration compared to acceleration. A worn or loose BOTTOM t/c will tend towards being both louder and higher pitch on deceleration compared to acceleration. Adjust t/c as per Grant's advice and warning.
  • How long does the rattle persist? If it disappears immediately the engine gains moderate rpm and good oil pressure, it is almost certainly slap in the lower chain. If it persists because of inadequate oil pressure (pump wear, failing bypass valve) or leaking chain tensioner, you are in for a big but not impossible rebuild.
By now, you may well have it all sorted, but please let us know.
Cheers mate,
Ken
 
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  #162  
Old 03-18-2016 | 06:18 AM
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Originally Posted by cat_as_trophy
  • How long does the rattle persist? If it disappears immediately the engine gains moderate rpm and good oil pressure, it is almost certainly slap in the lower chain. If it persists because of inadequate oil pressure (pump wear, failing bypass valve) or leaking chain tensioner, you are in for a big but not impossible rebuild.
By now, you may well have it all sorted, but please let us know.
Cheers mate,
Ken
Thanks Ken,

Rattle lasts about 1 km of driving from a cold start, but only under load.

We had a go at tensioning the chains last Sunday, a bit of an improvement, Going to remove the cam covers and check everything when time allows.
Been tied up this week relocating the MIL form Armidale to Brisbane again. Hopefully the last move.

Oil pump, chains...... Actually complete short motor is a new rebuild from Murray at Peninsula Jag Engine Centre. So nothing there should b worn or weak. I spoke to Murray during the week, same thing. He thinks upper chains need tensioning.
 
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  #163  
Old 03-19-2016 | 08:37 AM
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Dr Phill is here tonight, but guess what!
We are not playing Jags, just sitting in the garage talking about rear shocks and having a beer. Rear end is too sloppy for Lakeside.
Making a plan for the track day.
 
  #164  
Old 03-19-2016 | 08:47 AM
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Dr Phill has driven a few high performance cars in his day ( rally cars and championship circuit cars) (about 23 years ago) and wont drive the wallowing back end before some new shocks are fitted. My shout for a great mate.

Dr Phill
 
  #165  
Old 03-19-2016 | 10:34 AM
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Ya know, Clarke, it seems to me a not unfortunate occurrence that you lost that head gasket, although Grossly inconvenient, because you have a new engine out of it, and before you're finished, you (and Dr. Phill) will have almost completely rebuilt the Whole Entire Car!

In less than 2 years (counting from the fire)!
Amazing!
(';')
 
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  #166  
Old 03-19-2016 | 11:01 AM
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Originally Posted by LnrB
Ya know, Clarke, it seems to me a not unfortunate occurrence that you lost that head gasket, although Grossly inconvenient, because you have a new engine out of it, and before you're finished, you (and Dr. Phill) will have almost completely rebuilt the Whole Entire Car!

In less than 2 years (counting from the fire)!
Amazing!
(';')
It is amazing what 2 blokes with major shares in a brewery can achieve in a day!
 
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  #167  
Old 03-19-2016 | 11:37 PM
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Clarke,

I was thinking about this thread just now whilst re-energising a Triumph 2000 for my mate who has sold it.

How bloody sad is it getting when your damn car interrupts my thoughts when doing my magic on a non-Jaguar, fair dinkum, must be the withdrawals, HA.

That rattle had me going back.

My various S2's had a very strange rattle, and drove me to more drink at the time. Eventually found to be the glamourous heatshield on the exhaust manifold doing obscene things to the manifold itself, just at the folded edge right at the front. It also lasted about 1 km or so, then went away as heat expanded things.

I would also be laying a HUGE spanner on that front crank bolt again, just to be sure. They do loosen up after being disturbed. Usually a "clonking" noise more than a rattle, but would do no harm anyway.
 
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  #168  
Old 03-19-2016 | 11:55 PM
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Grant, the heat shield was removed because of the annoying rattle the day after the new engine went in. A job to look at another day, then again the exhaust manifold is much nicer to look at.

I will have a go at the crank bolt too when when we get around to checking the upper cam chains again. Nipping it up last weekend did make a bit of difference, but the rattle is still there. Just not quiet as noisy.
 
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  #169  
Old 05-03-2016 | 03:03 AM
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Cold start rattle is still there, pretty sure it is not coming from the top chains.
We have followed the engine builders instructions all the way(except missing the 1500km oil change by 24 km).
Dropped the car off today to the engine builder(3 hour round trip) to get it sorted, We are hoping it isn't a lower chain tensioner.
 
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  #170  
Old 05-03-2016 | 03:45 AM
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Fingers crossed for you mate...
 
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  #171  
Old 05-03-2016 | 03:47 AM
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Originally Posted by Daf11e
Fingers crossed for you mate...
Good thing is if it is a lower chain rattle it is a warranty issue,bad thing is it may be an engine out job!
 
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  #172  
Old 05-03-2016 | 05:02 AM
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Was this helped by the weekends activities?
 
  #173  
Old 05-03-2016 | 07:03 AM
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Originally Posted by paulyling
Was this helped by the weekends activities?
No Paul, been doing it since first start up of the new engine. just had to wait until the track days were over before committing to the car being off the road.
The rattle is something that won't harm the engine in the short term, just annoying and shouldn't be there after spending 6k on it.
 
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  #174  
Old 05-03-2016 | 09:08 AM
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Oh Drat!
I Hate it when something like this happens!
At least you got all your serious playing done.
(';')
 
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  #175  
Old 05-04-2016 | 12:23 AM
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Sounds promising, jockey pulley off the power steering has been replaced. Not a part of the new engine so not warranty, but good to have it sorted.
He is going to do a cold start tomorrow just to be certain.
 
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  #176  
Old 05-04-2016 | 08:08 AM
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Clarke:


1. Kidding: quite or quiet? You or the machine, I think they out think us, so they think, and type what they want!!!!


2. Glad it seems to be a rather simple "jockey" pulley. We call them "idlers". My lump uses one to tension the serpentine drive belt. My shipper/shredder uses one as a sort of clutch. That critter eats belts.


3. In past domestic critters, one got so loose, it jumped a tooth. It quite running, it had sounded like shot in a can.


4. Way back when, I tried to time a customer's straight eight in his 37 Olds. it would run, but with no power, quiet, though??? The shop pro diagnosed a slipped chain. Major job on that really big car to fix.
tons of tin to remove to get access. He used words I, as a kid had never heard. and, I knew more than a few of them!!


5. Critters in the recent past used single row chains. cheap and some
if not most go slack quick. The good ones are double row and life
is almost infinite.


6. A rough check for a chain outta the car is to hold it put parallel to the ground. should be little or no droop. Replace if any question.


7. Old Chevrolet 6's used a fiber gear on the cam and a steel mate on the crank. Bad habbit of loosing teeth in the most difficult places.
One of mine did that in a small town in Northern Germany. someone was looking after me. The local shop more used to fixing tractors, fixed it..... One of their toys was an ancient truck. A 29 or so Chevrolet. Same basic engine.


8. My 41 Studebaker Champion shreded one as I came to work. engine quit, but I coasted in. Kindly boiss et me fix it between customers. Not all that bad a job. Diagnosed, when I noted the distributor rotor didn't rotate when I cranked the engine...


9. As these Jaguars use "coil over shocks", will swapping the shocks change the "coils"? If not, the swing and sway may remain, albeit probably diminished. Bigger coils, stiffer ride, but more stable when pressed???


Carl
Carl
 
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  #177  
Old 05-04-2016 | 08:09 AM
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PS:


Not an original idea: Add a sway bar aka XJS!!!


Carl
 
  #178  
Old 05-05-2016 | 05:27 AM
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Noise still there today, possibly cam sprockets. Becomes warranty again. So he is on to it tomorrow for more investigation. Problem is he leaves for an OS holiday on the weekend, not really an issue to me. I have two vehicles I can use while it is waiting for a solution.
 
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  #179  
Old 05-05-2016 | 06:43 AM
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Originally Posted by o1xjr
Grant, the heat shield was removed because of the annoying rattle the day after the new engine went in. A job to look at another day, then again the exhaust manifold is much nicer to look at.
Lots of stuff to choose from these days. Ive been looking at heat shields, sleeves, tapes, ceramic coating etc a bit lately. Amazing whats available. Later I guess, some more fundamental stuff to overcome first. Good luck with sorting it out.
 
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  #180  
Old 05-06-2016 | 10:53 PM
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Car is back home with new cam sprockets fitted, still have the cold start rattle. It is a noise he is not familiar with and needs more investigating. The plan now is leave the car with him when we head overseas in June.
Out of this so far he has sorted a couple of small niggling issues for me, replaced a shim in the head to fix a small tapping, and replaced the oil pressure gauge sender so I know what the pressure is doing all the time now.

I am more than happy with the after sales back up and communication so far, and the attention to detail he has shown with small things I overlooked or not bothered with sorting yet.
 

Last edited by o1xjr; 05-06-2016 at 10:58 PM.


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