Knocking liner
Discussion
HELP !
Before I end up divorced or bankrupt (or both) can anybody provide advice on the implications of a liner that's shifted and causing slight knocking when warm ?
Probably due to excessive heat caused by an incorrect air/fuel mixture but is it possible to fix without removing the block and replacing all liners ?
What will happen if nothing is done ?
Before I end up divorced or bankrupt (or both) can anybody provide advice on the implications of a liner that's shifted and causing slight knocking when warm ?
Probably due to excessive heat caused by an incorrect air/fuel mixture but is it possible to fix without removing the block and replacing all liners ?
What will happen if nothing is done ?
I would get it sorted straight away! 
The liner is steel the block is aluminium. I have not heard of this before but suspect it might happen hence the "Top Hat" variety favoured by some.
If the liner is moving up and down in the block, it won't be long before something gives in a big way.
The offending liner can be replaced, but what are the rest like?
>> Edited by ian8542 on Tuesday 9th November 08:54
The liner is steel the block is aluminium. I have not heard of this before but suspect it might happen hence the "Top Hat" variety favoured by some.
If the liner is moving up and down in the block, it won't be long before something gives in a big way.
The offending liner can be replaced, but what are the rest like?
>> Edited by ian8542 on Tuesday 9th November 08:54
Boosted LS1 said:
What makes you think it's a liner fault and not a bit of piston slap or something else? Are you loosing coolant, steaming?
Boosted.
I am technically inept in this area and had no idea there was a problem. The car is currently with a guy who builds hi-po V8's in order to try and find why I get intermittent power loss. Immediately he heard the engine he asked how long had it been knocking and did it do it when cold. I had never even noticed anything.
Turns out it does only do it when hot and only slightly but he reckons the heads should come off to start with as a liner may be shifting. He scared me talking about new blocks and holes behind liners you can't see.
The car isnt losing any coolant or getting overly hot - sits there at 90 when stationary (measured onto the rad) with the fans cutting in and out.
Anyway the chap reckons he has sorted the power loss issues - I will post reasons why once I have picked the car up tpmorrow and spoken to him in depth.
Is there any way of telling piston slap or something else from a shifting liner without taking the heads off ?
I don't know the detailed design of the engine, but I would have thought that if the liner was moving you would get a lak somewhere. Either coolant into the oil or combustion gases into the coolant. I can't think of any way to tell the situation without taking the head off. Perhaps someone with more experience of this engine can offer more help.
Being blunt, it sounds like a load of scaremongery to me. When a rocker tip insert broke on my SEAC I was told by most people it was the cam, a dealer even told me the block was bent causing excessive tappet noise and I needed a new short engine.
It was only when I was convinced to have the engine stripped down that the minor and easily fixable fault was found.
Taking the heads off is time and money consuming. I know if you take the sump off you can see all the bores and liners, that may show if something funny is going on. It's also worth taking a big end shell off and checking that, they are relatively cheap to replace. Although my shells didn't need replacing, I had them all done anyway and the engine sounded better for it afterwards. My engine had done about 33k at the time and it was strange that a little cold start "piston slap" seemed to disappear afterwards.
It was only when I was convinced to have the engine stripped down that the minor and easily fixable fault was found.
Taking the heads off is time and money consuming. I know if you take the sump off you can see all the bores and liners, that may show if something funny is going on. It's also worth taking a big end shell off and checking that, they are relatively cheap to replace. Although my shells didn't need replacing, I had them all done anyway and the engine sounded better for it afterwards. My engine had done about 33k at the time and it was strange that a little cold start "piston slap" seemed to disappear afterwards.
I hope the car is ok but if not, why don't you ask somebody to pressure test the coolant and see if the pressure drops, thus indicating a leak. I agree, it seems like an ott diagnosis unless some proper tests have been done.
It could be something really simple!
Or, post Rob at V8D who chats on here. He's seen plenty of RV8's with problems
Boosted.
It could be something really simple!
Or, post Rob at V8D who chats on here. He's seen plenty of RV8's with problems
Boosted.
Don't mean to be a pessimist,but this could be a possibility.
Before I had a TVR,I had two 3.5 Rovers,the original being a P6.
One day after towing a friends car,i noticed a tapping from the engine( it sounded like a dodgy lifter). It only happened when warm,and after months of trying various ways to get rid of it(new cam/lifters along the way) eventually tracked it down when i removed one of the heads and discovered a piston sized ring laying on top of one of the bores. Closer inspection revealed it to be a section of the Tin head gasket,which had been cleanly punched out!
you could see the liner was loose by leaning on the liner with a screwdriver. I had the block out,had a new liner installed by a local engineering firm,and the noise was gone.However another six months later the tapping returned,and it turned out to be an adjacent cylinder doing the same thing:-(
this time i decided to scrap the block,I assume at some point in its past it had been seriously overheated,or i was just unlucky ??.£100 for a breakers yard block had me going again.
Hope this helps
Andy
Before I had a TVR,I had two 3.5 Rovers,the original being a P6.
One day after towing a friends car,i noticed a tapping from the engine( it sounded like a dodgy lifter). It only happened when warm,and after months of trying various ways to get rid of it(new cam/lifters along the way) eventually tracked it down when i removed one of the heads and discovered a piston sized ring laying on top of one of the bores. Closer inspection revealed it to be a section of the Tin head gasket,which had been cleanly punched out!
you could see the liner was loose by leaning on the liner with a screwdriver. I had the block out,had a new liner installed by a local engineering firm,and the noise was gone.However another six months later the tapping returned,and it turned out to be an adjacent cylinder doing the same thing:-(
this time i decided to scrap the block,I assume at some point in its past it had been seriously overheated,or i was just unlucky ??.£100 for a breakers yard block had me going again.
Hope this helps
Andy
Certainly worth checking with the endoscope.
I would have thought, with my very limited knowledge of the top half of these engines, that if the liner was loose it would be messing about with the head gasket. I have been told that the distances between bores on the 450's is so small that head gaskets often cause problems. It was one reason I went for a 420 rather than a 450, but that was probably scaremongery aswell. Wouldn't a loose liner knacker the hell out of a thin area of gasket causing the two cylinders to lose compression and poor running? Just a thought.
I would have thought, with my very limited knowledge of the top half of these engines, that if the liner was loose it would be messing about with the head gasket. I have been told that the distances between bores on the 450's is so small that head gaskets often cause problems. It was one reason I went for a 420 rather than a 450, but that was probably scaremongery aswell. Wouldn't a loose liner knacker the hell out of a thin area of gasket causing the two cylinders to lose compression and poor running? Just a thought.
Thanks for all the advice.
All this talk of an endoscope is making my cheeks go taut
I understand that any movement is pretty hard to detect even with the head off and that you need to try and flick the top edge of the liner with a sharp knife. If you can feel the edge then it has moved.
I am pretty sure there was a bit of scaremongery and the guy has said the first sign I will get is of a loss of coolant followed by a head gasket failure.
I am still trying to understand it - if a liner has shifted what exactly causes the knocking ?
Does it move slightly when hot and then shrink back - otherwise why only the sound when hot ?
All this talk of an endoscope is making my cheeks go taut
I understand that any movement is pretty hard to detect even with the head off and that you need to try and flick the top edge of the liner with a sharp knife. If you can feel the edge then it has moved.
I am pretty sure there was a bit of scaremongery and the guy has said the first sign I will get is of a loss of coolant followed by a head gasket failure.
I am still trying to understand it - if a liner has shifted what exactly causes the knocking ?
Does it move slightly when hot and then shrink back - otherwise why only the sound when hot ?
chunder said:
I am still trying to understand it - if a liner has shifted what exactly causes the knocking ? Does it move slightly when hot and then shrink back - otherwise why only the sound when hot ?
I'm no expert in this but thermal expansion of aluminium is greater than that of steel so as it gets hotter the hole in the block would expand away from the liner assuming all temperatures are the same. When cooling down the block would clamp back down onto the liner.
I did read somewhere that the liners are cast in to the block which would mean that normally they would be fused together so the different rates of expansion would just result is stresses.
I'd have to say that for someone to diagnose this by sound alone they must have pretty magic ears or be trying to pull the wool over someone's eyes!
I doubt that there is a quick and easy way to confirm what's going on but a comparison of compression tests hot and cold might give you a clue.
Best of luck
Leo
Hi
Loose liners are not unknown on these engines, but it does not mean that you will automatically loose oil, water or mix the two. These liners fit into the engine casting, and do not seal the water jacket. Only if the engine casting between the water jacket and the back of the liner is split will you loose water, and the only evidence will be a dropping water level and no idea where its going (Actually straight out of the exhaust). Luckily damage this bad seems to be related to range rovers/land rovers where excessive cylinder temperatures build up when towing and are compounded by a weak mixture. I suggest that you speak with RPI Engineering in Norwich. What they dont know about these engines aint worth mentioning. Good luck
Loose liners are not unknown on these engines, but it does not mean that you will automatically loose oil, water or mix the two. These liners fit into the engine casting, and do not seal the water jacket. Only if the engine casting between the water jacket and the back of the liner is split will you loose water, and the only evidence will be a dropping water level and no idea where its going (Actually straight out of the exhaust). Luckily damage this bad seems to be related to range rovers/land rovers where excessive cylinder temperatures build up when towing and are compounded by a weak mixture. I suggest that you speak with RPI Engineering in Norwich. What they dont know about these engines aint worth mentioning. Good luck
ian8542 said:
I would get it sorted straight away! 
The liner is steel the block is aluminium. I have not heard of this before but suspect it might happen hence the "Top Hat" variety favoured by some.
If the liner is moving up and down in the block, it won't be long before something gives in a big way.
The offending liner can be replaced, but what are the rest like?
>> Edited by ian8542 on Tuesday 9th November 08:54
The liner is steel the block is aluminium. I have not heard of this before but suspect it might happen hence the "Top Hat" variety favoured by some.
If the liner is moving up and down in the block, it won't be long before something gives in a big way.
The offending liner can be replaced, but what are the rest like?
>> Edited by ian8542 on Tuesday 9th November 08:54
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