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For all things Rover V8, the TVR Griffith and Chimaera and TVR T-Cars
One of the most frequent search criteria, both internally on this site and via search engines, is liners, and one of the most popular questions is “What are they?” And what often follows is a request to define flanged (top-hat) liners.
The aluminium alloy the engine block is cast from is quite strong but would not last long if the piston rings were pounding up against it 6000 times a minute. So a cast iron liner, something like the tube in the middle of a toilet role, is inserted into each bore for the piston to run in.
There are two main subdivisions of liners: wet and dry, the difference being whether water runs up against the liner or the liner fits against the aluminium. The RV8 is a dry-liner engine although it is probably the wettest dry-liner engine around. It has a reputation for having ‘porous’ blocks but this description does not adequately explain the situation.
Forgetting the original Buick engines, there are two bore sizes in RV8s: the original 88mm of the 3.5 and the 94mm of all the other engines of 3.9 litres and above. The porosity problem in very rare in the 3.5 and this gives a hint as to its cause.
When an engine suffers fluid loss with a leak being apparent, the norm is that coolant is finding its way into the combustion chamber. Many people assume this means they have a warped head but this is not often the case as the main cause for such warping is overheating, not the other way around.
The probable cause is problems with the liners.
The good thing about the RV8 is that it is old technology and pushrods make for easy head removal. Just a few bolts and off everything comes. The head can be checked for warping by jobbing engineering companies but you can do some of the detective work yourself.
The head gasket is the first place to look. If owners have not been scrupulous when replenishing the radiator
and not using the correct amount of anti-freeze, the water channels can become corroded. Aluminium can be dissolved in water as it can be slightly acid and the anti-freeze carries has an anti corrosive function. What can happen in that the gap between a water channel the combustion chamber can become so narrow that the coolant will seep through. This tends to leave evidence by way of staining on the block, head and gasket. This can be repaired or the head can be replaced by a new or refurbished one. And that might be enough to cure the problem.
However, check your liners.
The liner in the Rover V8 is what is called an
interference or press fit meaning that it has to be pressed into position with some degree of force and the compression of the liner keeps it in place via friction. The expansion rates of steel and aluminium vary and as the engine warms the friction increases. Despite the forces present in the combustion chamber and the energy transmitted to the liner by the reciprocating piston, the norm is that it will remain in situ for the life of the engine. However when bored out to 94mm the walls of the water jacket become quite thin and great care was needed to ensure that the bore centres were spot on. But this need sometimes went unfulfilled.
Water can seep into the gap between the liner and bore walls from small, and not so small, cracks and pinholes in the water jacket. In theory this is not a problem but the combustion process forces this water up the cylinder liner, past the angled lip, under the head gasket and into the combustion chamber.
Further, the fluid that is running between the liner and the block is an excellent lubricant and the press fit is interfered with and, under the force of the friction from the pistons rings, the liners can move. They won’t move far and then almost always downwards. Slipped liners give few symptoms, reduced compression being one, but the norm is that there will be a coolant leak into the combustion chamber as well.
The way to recognise if a liner has slipped is, once the head has been removed, to compare all four pots. If one is significantly lower then there’s a problem.
With the original liners the top of the flange is within the cut-out for the combustion chamber in the head gasket. This means that any fluid coming up the side of the liner has a free route into the combustion chamber.
This would appear to be a major cause for water loss and overheating where there is no apparent leak.
It should be noted that despite people referring to the problem as leaking liners this is rather inaccurate as it is the bore that has the leak. However, liners can crack causing the fluid to seep directly into the cylinder bores.
So what to do? The answer is not simple but it is final.
The classically simple solution is to replace the angled top to the liner with a flange. This requires a degree of accurate cutting of the block around the cylinder bore with sophisticated machinery.
The flange at the top is quite apparent. What is less noticeable is the cunning little seal at the bottom which effectively gives the liner all the attributes of a wet liner, allowing no route for sump pressure to go up, nor water to find its way down. This works in tandem with the flange.
The flanged liner has a number of benefits when compared to the original. It can be appreciated that it is much more positively located. The flange is a press fit into the rebate machined into the head by Turner Engineering and provides a much better seal. Pressurised cooling fluid is effectively stopped from finding its way into the combustion chamber as the edge of the flange is covered by the headgasket so stopping any leakage.
When the head is bolted down it acts upon the flange, forcing it into its seat and, of course, creating the seal. And, because of the way it is located there is no chance of the liner slipping.
The new liner can be made of ductile cast iron which is much stronger than the normal spun cast iron, so making it more suitable for high performance engines.
So far so good and if that was all there was to it, it would be satisfactory. However, there is more.
Near the bottom of the liner, and on the outside, is a seal. This effectively changes the RV8 into a wet liner engine so that even if there is a coolant leak through a crack or hole in the bore behind the liner it
Right: A selection of non-flanged, ‘normal’ liners. If the image isn’t that clear then imagine a toilet roll inner for really posh people. I mean, really posh.
Right: A somewhat crude representation of a cross section through the section between two bores on an RV8.
The blue is the cooling fluid, the light grey the aluminium alloy engine block, the medium grey a section through the liner wall and the dark grey bit at the top the head gasket.
As can be seen, if any fluid escapes through the wall of the block to the area between the liner and the bored out wall, it can work its way upward then into the combustion chamber.
NOT TO SCALE
Our thanks to Turner Engineering for their assistance in the creation of this article. First two photographs courtesy of Westwood Cylinders
All other picture, copyright RV8R.
Right is a non-flanged liner block with liners in situ. Compare it with the just rebated block below which is awaiting liners.
 The much narrower space between the bores is noticeable, hence the headgasket will cover the top of the flanged liners when fitted. The picture below was taken at Turner Engineering. The rebated liners also have a seal at the bottom which effectively stops any fluid going up or down between liner and wall.
Coolant under pressure makes its way through any cracks in the cylinder wall.
Any coolant that does manage to escape into the gap between liner and wall will find no escape at the top of the bore as the flange is now sealed by the headgasket. The flange also locates the liner meaning that it cannot drop.
Flanged liners

One of the most frequent search criteria, both internally on this site and via search engines, is liners, and one of the most popular questions is “What are they?” And what often follows is a request to define flanged (top-hat) liners.

The aluminium alloy the engine block is cast from is quite strong but would not last long if the piston rings were pounding up against it 6000 times a minute. So a cast iron liner, something like the tube in the middle of a toilet role, is inserted into each bore for the piston to run in.

There are two main subdivisions of liners: wet and dry, the difference being whether water runs up against the liner or the liner fits against the aluminium. The RV8 is a dry-liner engine although it is probably the wettest dry-liner engine around. It has a reputation for having ‘porous’ blocks but this description does not adequately explain the situation.

Forgetting the original Buick engines, there are two bore sizes in RV8s: the original 88mm of the 3.5 and the 94mm of all the other engines of 3.9 litres and above. The porosity problem in very rare in the 3.5 and this gives a hint as to its cause.

When an engine suffers fluid loss with a leak being apparent, the norm is that coolant is finding its way into the combustion chamber. Many people assume this means they have a warped head but this is not often the case as the main cause for such warping is overheating, not the other way around.

The probable cause is problems with the liners.

The good thing about the RV8 is that it is old technology and pushrods make for easy head removal. Just a few bolts and off everything comes. The head can be checked for warping by jobbing engineering companies but you can do some of the detective work yourself.

The head gasket is the first place to look. If owners have not been scrupulous when replenishing the radiator and not using the correct amount of anti-freeze, the water channels can become corroded. Aluminium can be dissolved in water as it can be slightly acid and the anti-freeze carries has an anti corrosive function. What can happen in that the gap between a water channel the combustion chamber can become so narrow that the coolant will seep through. This tends to leave evidence by way of staining on the block, head and gasket. This can be repaired or the head can be replaced by a new or refurbished one. And that might be enough to cure the problem.

However, check your liners.

The liner in the Rover V8 is what is called an interference or press fit meaning that it has to be pressed into position with some degree of force and the compression of the liner keeps it in place via friction. The expansion rates of steel and aluminium vary and as the engine warms the friction increases. Despite the forces present in the combustion chamber and the energy transmitted to the liner by the reciprocating piston, the norm is that it will remain in situ for the life of the engine. However when bored out to 94mm the walls of the water jacket become quite thin and great care was needed to ensure that the bore centres were spot on. But this need sometimes went unfulfilled.

Water can seep into the gap between the liner and bore walls from small, and not so small, cracks and pinholes in the water jacket. In theory this is not a problem but the combustion process forces this water up the cylinder liner, past the angled lip, under the head gasket and into the combustion chamber.

Further, the fluid that is running between the liner and the block is an excellent lubricant and the press fit is interfered with and, under the force of the friction from the pistons rings, the liners can move. They won’t move far and then almost always downwards. Slipped liners give few symptoms, reduced compression being one, but the norm is that there will be a coolant leak into the combustion chamber as well.

The way to recognise if a liner has slipped is, once the head has been removed, to compare all four pots. If one is significantly lower then there’s a problem.

With the original liners the top of the flange is within the cut-out for the combustion chamber in the head gasket. This means that any fluid coming up the side of the liner has a free route into the combustion chamber.

This would appear to be a major cause for water loss and overheating where there is no apparent leak.

It should be noted that despite people referring to the problem as leaking liners this is rather inaccurate as it is the bore that has the leak. However, liners can crack causing the fluid to seep directly into the cylinder bores.

So what to do? The answer is not simple but it is final.

The classically simple solution is to replace the angled top to the liner with a flange. This requires a degree of accurate cutting of the block around the cylinder bore with sophisticated machinery.

The flange at the top is quite apparent. What is less noticeable is the cunning little seal at the bottom which effectively gives the liner all the attributes of a wet liner, allowing no route for sump pressure to go up, nor water to find its way down. This works in tandem with the flange.

The flanged liner has a number of benefits when compared to the original. It can be appreciated that it is much more positively located. The flange is a press fit into the rebate machined into the head by Turner Engineering and provides a much better seal. Pressurised cooling fluid is effectively stopped from finding its way into the combustion chamber as the edge of the flange is covered by the headgasket so stopping any leakage.

When the head is bolted down it acts upon the flange, forcing it into its seat and, of course, creating the seal. And, because of the way it is located there is no chance of the liner slipping.

The new liner can be made of ductile cast iron which is much stronger than the normal spun cast iron, so making it more suitable for high performance engines.

So far so good and if that was all there was to it, it would be satisfactory. However, there is more.

Near the bottom of the liner, and on the outside, is a seal. This effectively changes the RV8 into a wet liner engine so that even if there is a coolant leak through a crack or hole in the bore behind the liner it cannot go anywhere else. Further, there is no possibility of the gasses from the combustion finding their way into the cooling system.

‘Porous’ bores was a case of development highlighting a weak point in the original design. Flanged liners overcomes the problem in an elegantly simple way. The problem occurs with 3.5 Rover engines but not with the frequency with which it occurs with engines with 94mm bores.

A bit of a discussion on slipped liners with a lovely example of what one looks like. I disagree with a few things Ken says. The liner does not move up and down with the piston and whilst overheating might cause slipped liners it is by no means the only, or perhaps main, one.
The most significant thing to ignore is the suggestion that it costs $6000 dollars to solve a slipped liner as the block is unrepairable. Turner Engineering in Sussex should be contacted before putting your block into the recycling bin.
Despite the title of this video, it doesn’t show a way of testing for a slipped sleeve so much as a ‘porous’ block. See above for a crude diagram. That said, the lubricating effect of a water leak can give rise to a slipped liner.