Newly aquired Disco2, issues!!

Hi I have aquired a Disco 2, V8 'Thor' engine with a 5 speed box but I have two issues with the engine.

I think at some point it has overheated and its possible someone has tried to hide this issue as the temp guage is as dead as a doornail, either that or the sensor has failed

The other issue which leads me to belive the engine has got hot is an odd almost tappet like noise which only occours when the engine is at running temperature, I have a bad feeling this may be a slipping liner, although the car does not seem overheat, loose water, pressureise or any of the other fun and games I have seen before. Is it possible for the block to expand with what and loose grip on the liner to allow it to move? The engine does pull very very well, certainly no aparent loss of power, missing or anything else

If it is dead, can I fit my 3.9 from my termainlly rotten RRC Vogue SE? (Which has turned out to be a JE engineering X bolted and Top hat block) I suspect so but things like the lack of distributor and a few other details I am not hopfull of a straight swap

Is the guage run off the engine management or is there a sensor for it? before I do anything I want that working!

It could just be a sticking tappet making the noise or worse a camshaft lobe worn,I would do a couple of short oil changes and fix the temp gauge pronto !

I have investigated this a little more (see my thread on the temp guage) turns out teh temp guage had been disabled inside the instrument cluster, all fine now (if you ignore the taped over warning lights!). The engine runs at normal temp, guage pointing halfway and tapping noise aside seems to have no other issues, however I guess it is safe to say it has had hot running issues in the past.

I've had a listen with a stethoscope and the noise would appear to be originating from the top of the right hand bank which leads me to belive the tappets and cam are probably fine, that and that normally those will rattle when cold and disapear when warm. I am hopfull its not a slipping liner as the tap is a 1/4 engine speed and i would expect a tap caused by a liner to be at engine speed and am leaning towards the valve rocker arms.

Howevr the THOR engine looks a real pain to get the rocker cover off and it seems to have really irritating fastners on it

The cause of the tapping noise when hot has been found and its not good news...

as you can see, the liner has shifted but not by a lot. I have acquired a GEMS 4.6 short engine, allegedly one that was built by Turner Engineering in 2008, I know I have to do something with the crank sensor and possibly swap the cam sprockets?

Zaphod said:

The cause of the tapping noise when hot has been found and its not good news...

as you can see, the liner has shifted but not by a lot. I have acquired a GEMS 4.6 short engine, allegedly one that was built by Turner Engineering in 2008, I know I have to do something with the crank sensor and possibly swap the cam sprockets?

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if only they had designed these engines that bit better,non of these slipped liner issue's might not have occurred.

gemsdad said:

if only they had designed these engines that bit better,non of these slipped liner issue's might not have occurred.

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The design is not a problem, the execution is, this is a manufacturing defect! The liner was not pressed full home before final machining of the deck, as these later blocks have a seat for the liner to sit on, if correctly fitted they can't move no matter what, however at 15 years old the warrantee is out!

Zaphod said:

The design is not a problem, the execution is, this is a manufacturing defect! The liner was not pressed full home before final machining of the deck, as these later blocks have a seat for the liner to sit on, if correctly fitted they can't move no matter what, however at 15 years old the warrantee is out!

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the design of the engine is at fault,the liner slips on these engines,it is a very common problem.that is why they came up with a TOP HAT liner to alleviate this problem.when the liner slips it causes pressurisation of the cooling system usually.take a read on this issue and you will see how and what causes it.

gemsdad said:

the design of the engine is at fault,the liner slips on these engines,it is a very common problem.that is why they came up with a TOP HAT liner to alleviate this problem.when the liner slips it causes pressurisation of the cooling system usually.take a read on this issue and you will see how and what causes it.

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I think its you that needs to read up on the modifications to the THOR engine block, what you say is quiet correct with regards to the earlier blocks, on those it was nothing but a press fit holding the liner in place, and the bore into which the liner was pressed could in fact start being eaten away by the crank with catastrophic results. However the later THOR blocks have a seat at the bottom of the bore, and the liner should be pressed right down on it, then the top deck is machined if done correctly the bottom of the liner is up against the seat and the top is right up against the head, there is no way it can move. Any slipping liners on a THOR engine are pure shoddy workmanship in not pushing the liners fully home before machining the top deck. Slipping liners alone do not make the cooling system pressurize, this one had no signs of either water use or pressurisation

Shown below is a sectioned THOR block with the lower ledge that the liner should be seated on cleearly visible, and also the reason the cooling system is so fragile is also clearly visible, on engines without the lower ridge and cracks in the water jacket will let the liner slip which is why so often they do, along with the other lovely issues you mention, but it's always after it has been allowed to overheat

Zaphod said:

I think its you that needs to read up on the modifications to the THOR engine block, what you say is quiet correct with regards to the earlier blocks, on those it was nothing but a press fit holding the liner in place, and the bore into which the liner was pressed could in fact start being eaten away by the crank with catastrophic results. However the later THOR blocks have a seat at the bottom of the bore, and the liner should be pressed right down on it, then the top deck is machined if done correctly the bottom of the liner is up against the seat and the top is right up against the head, there is no way it can move. Any slipping liners on a THOR engine are pure shoddy workmanship in not pushing the liners fully home before machining the top deck. Slipping liners alone do not make the cooling system pressurize, this one had no signs of either water use or pressurisation

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ok,duly noted.