Timing chain noise?

[oldtimer]

Thanks Martec, I was going to skip this thread but it seems you have sucked me into this tricky topic.
Before any reference to the engine let me remind you of the state of play during the sixties. My recollections are that the roads comprised of bends joined together with odd straight bits and the occasional dual carriage way. I am not sure when the first Motorway opened but I never went on one. There was no 70mph speed limit only the urban 30mph limit. Lorries carried a 20mph Max speed plate on the rear - can you imagine that. So the Jaguar had a fairly low axle ratio to give maximum acceleration past slow lorries and many cars of that period. Still a number of pre war cars on the road at that time. Taking all this into account one can understand why some consider the gear/ axle ratio for Motorway driving as unsatisfactory.
I was involved in overhauling XK engines during the sixties and found that they were completely Knackered at 70/80 K. So, I have to ask what evidence is there that this particular engine has actually achieved 140K ? Trip recorders returned to Zero 99999 miles. I would venture that it may have had some mid life attention and if your mileage is correct then it is ready for a major overhaul.

This subject started in respect to chain rattle. Both chains and sprockets wear, chains stretch and sprockets wear the teeth to sharp points.
Wrap a new chain around an old sprocket and then lift the chain at the top centre and see the slack in the chain. So the quickest way to knacker a new chain is to put it on an old sprocket.

FOR SOME REASON I HAVE LOST THE TEXT WHEN I HAVE PRESSED THE SUBMIT BUTTON SO EXCUSE THE BREAK WHILE I TRY TO SUBMIT

[oldtimer]

GOOD HEAVENS IT WORKED
The top chain has a guide down each side. Care needs to be taken when tensioning the chain. Tensioning is the wrong word lets say removing the slack from the chain. If the chain is too tight it will growl at you so it needs to be backed off so you can feel some slack , turn the engine over in the direction of rotation and feel for slack down the right hand side , don't turn the engine counter clock wise . It really is a matter of feel !

The bottom chain has a hydraulic tensioner on the left hand side looking at the front. I suspect the lump you claimed had sheared off was indeed the hydraulic tensioner that had been worn/ blown out. This detail requires more explanation but not tonight.

Martec mentions cylinder bores - they may look nice and shiny but are probably well worn - did you do a compression test before you removed the cylinder - a leak by check is rather more accurate but a bit late with the head off -

With the cylinder head off, due consideration needs to be given as well as the mains and big ends - this story goes on and on.

Tis past my bedtime so that's all for tonight

Oldtimer

[oldtimer]

Simon,
I have been thinking today about the job you have started on your motor. We are not sure of your experience in regard to what is becoming a pretty big job. I'm sure we are all willing to help but don't want to teach granny to suck eggs - if you know what I mean .

Have you considered purchasing a Genuine Jaguar Workshop Manual ?
This contains all that you need to know in respect to an engine rebuild. Armed with that knowledge you will be in a better position to ask questions regards procedures you may not fully understand.

The timing chain cover can be removed by using a stud box to remove the four vertical studs in the head.

Two dowels ensure the timing chain cover is correctly located. These dowels are crucial to ensure the front end of the double sprocket spindle locates and correctly aligned into the chest cover aperture.

Stripping the engine down is fairly straight forward but I do worry somewhat in regard to the rebuild.

Do let us know your progress

[Martec]

Three posts in a row from you Phil! you are getting quite wordy. It is quite an expensive task to rebuild these engines. The welsh outfit (always reasonable) charge 5 grand.

As usual I rebuilt my own engine after the machining, my chain wheels were surprisingly still OK, but It cost me £2,000 and the Welsh outfit would also charged £2,000 at that time. That was 17 years ago and it has only needed the chain retensioned a few years back.

If there is a lip at the top of the bore (just down from the top) then it needs a rebore and oversize pistons. The bearing shells will show signs of wear, but if a different metal colour is showing (copper or at worst steel backing), then a crank regrind is necessary and probable balance.

Do you have the history of your car and engine?

Best wishes
Brian

[SimonF]

Gents,

Thanks for the comprehensive replies. It is good to know there is support on here.

The engine is in good health and I assume it has been worked on in the past. Vehicle shows 39,100 miles on odo and history backs up that it has gone round once. Compression ratios were spot on before strip. No smoke from exhaust and piston crown / head show no oil problems. Bores have no lip and honing is ok. I changed the block core plugs to check for sludge and it was all clear. I couldn't remove the sump, so I didn't check the crank bearings. Indicated oil pressure is correct, but I haven't measured with the capillary tube.

The sheared chain guide was the left hand lower looking front on at the engine, not the hydraulic tensioner. I have changed all sprockets (cam, intermediate and crank) along with all chain guides, hydraulic tensioner (inc gauze).

Everything is now rebuilt and the engine timed and valve clearances adjusted. I just need to refit the radiator and carbs to finish off. Hopefully she'll be running by next weekend.

Regards
Simon

[Martec]

Nice to hear all is OK and you have avoided the horrendous cost of an engine rebuild, you have done well to have done all that work so quickly.

As far as oil pressure I ran a capilliary pressure gauge beside the old transmitter type for quite a few miles, at no time did they come anyware near the same readings! I have now rearanged my instruments and only have the capilliary gauge.

Brian

[oldtimer]

Hi Simon,
You have done well, Your first post implied to me that perhaps you were struggling a little , but clearly not. So all our hand wringing and agonising over your engine situation was all a bit unnecessary - never mind ,that's what the forum is all about.

I'm sure we will all be pleased to hear how it is performing after the road test.

Regards Oldtimer

PS I have never been a great fan of Haines manuals and would still recommend you acquire some proper Jaguar Manuals appropriate to your model

[SimonF]

Good morning all,

It took a little time to get to the road test stage due to other commitments!

However, initial road test complete. The chains are now quiet and the engine is running very well. I took the opportunity to purchase and fit a 123 ignition distributor during the rebuild, so I have been tuning the advance curves. The performance is now very strong compared to the original set up, so I assume either the timing was out or the mechanical distributor advance was stuck.

Now I just have to resolve a leaky cam cover and she is hopefully ready for the nicer weather.

Thanks again for the advice and guidance.

Simon

[Martec]

When you have solved the leaky cam cover joint please let us know how you did it, none of my 'fix's' seem to last more than 6 months before they leak again.
Brian

[SimonF]

Morning all,

A quick update. The engine is running well and with the new Bluetooth 123 ignition system set up, the torque over the speed / load range is brilliant.

Cam covers are sealed with RTV, but a couple of the cover nuts and washers are weeping oil, so need another go!

However, I do get an intermittent noise when pulling away. It sounds strange, almost like a squawking noise. As I've changed the water pump, engine mounts and checked for obvious things, I suspect either the belt tensioner or dynamo. Anyone had something similar?

Regards
Simon

[PPV]

Is yours a manual car? If so what about the clutch release bearing? It may be showing some sign of wear unless you know its condition. Hope it is something simpler like a slipping fan belt or dry bearing on dynamo or its belt tensioner. I had the latter go 'stiff' and a little WD40 followed by a drop of oil soon quietened things down. It is easy to check once the fan belt is slackened so start there I would think.
Let us know what you find and good luck.
Regards,

[SimonF]

Paul, thanks. A bit of oil on the belt tensioner spring and all quiet again.

Propshaft UJs gave up after a few runs, so I've had to change these. Took the opportunity to top up the gearbox and diff oil.

Also found that the manifold to downpipe nuts were only finger tight, so the slight ticking noise when cold that sounded like camshaft has also now been fixed.

It is very satisfying getting the car back to full health.

Next big job, hopefully I can delay it until winter is the crankshaft rear oil seal, which is leaking and making a mess wherever I park.

[SimonF]

Also, could somebody advise the correct CO reading at the tailpipes. I have a Gunson meter and want to set the mixture with this rather than the lifting pins in the carb.

Thanks

[Martec]

You are certainly going through this car and it is nice to hear you are doing it yourself? cheaper and more satisfying.

Two points, at 1965 I assume you will have the rope seal rear crankshaft seal, if you are unfortunate then it has the scrowl seal??!! My scrowl does not stop oil loss but I don't have any rust between the chassis rails. The rope seal requires the engine out, crank out, new rope seals and this HAS to be resized with the correct Churchill tool otherwise it can burn and severely damage the crank.

Mixture setting of the carbs, be very careful as if set too weak, or the choke carb not operating, they can spit back and cause a fire, read other posts on here about the results of fire, those unfortunates have not reappeared on here!

Best wishes
Brian