Repairing a 1979-2002 V8 engine with a dropped liner

What’s the worst thing the owner of a vintage V8 Land Rover can hear? For many, the words “Sounds like you have a dropped liner” are right up there with getting a venereal disease, catching polio, or receiving a visit from the criminal investigation unit of the IRS…
In this month’s column I’d like to talk about what to do when you hear those words. And if you think “when you hear those words” is too negative — after all, you made it this far without getting an STD, so why should you get a dropped liner… we’ll look at ways you can prevent them. I’m not a biology teacher or a doctor, and I don’t play one on TV, but I still have some ideas on liners that you may find useful, so read on…

The Land Rover V8 engine block is made from aluminum. The block is the part of the engine that holds the crankshaft, rods, and pistons. The pistons move up and down in cylinders, which are tubes drilled into the block. A V8 engine has eight of these pistons and cylinders, arranged in a V pattern when viewed from straight ahead. The rods connect the pistons to the crank, which translates the up-and-down motion of the pistons into the rotary motion that drives your Rover forward. Aluminum is light but it’s not very resistant to abrasion. For that reason, the aluminum is not used for the cylinder walls in Rover engines. Rover bores the aluminum block a little bit bigger than the required cylinder diameter. Then they press in hard steel tubes — precision machined pieces of pipe, really — called liners. The pistons move up and down inside these liners. The liners are hard enough to resist wear for hundreds of thousands of miles if properly maintained.

In addition to the holes for the liners the block has a number of other holes that carry oil and coolant throughout the inside of the engine. In fact, there are passages in the block that allow coolant to flow around the liners in several spots to carry away the excess heat of combustion. These coolant passages are one of the potential trouble spots in Rover engines. More on them later.

When the aluminum blocks are manufactured, a machine drills a set of eight cylinder bores a preset distance into the casting. Cylinder liners of a precise length are then pressed into the bores until they seat at the bottom and they are then machined flush with the top. They are held tightly in place by the cylinder heads, which bolt onto the engine block and cover the pistons and cylinders with combustion chambers. At least that’s the idea. It doesn’t always work out that way, though.

If you’ve read this far you are no doubt aware of the British mastery of automotive production quality. When the Rover engines were assembled some motors had the liner holes bored a bit too deep, and some liners were a bit too short, and some liners bottomed out on aluminum shavings that subsequently fell out. All these things left a little bit of room for the liners to be able to move up and down.

Now, the liner was pressed in pretty tightly and it would not just move up and down on its own. What does it take to make it move? You guessed it – heat. When a Rover engine overheats the aluminum block expands a little more than the steel liner, just enough that a liner can loosen up and start moving up and down with the movement of the piston. It only takes a few moments of up-and-down for the liner to wear away the aluminum enough that when the motor cools the liner will remain loose.

When this happens you end up with a light tapping sound coming from inside the engine. In the early stages the engine will still run well but the longer you drive it the looser it gets. I’ve seen engines last for thousands of miles in this state. But remember how we talked about those coolant passages around the liner a few paragraphs back? As the liner gets looser some of that coolant can start to leak into the cylinder, and combustion gases from the cylinder can leak into the coolant. When that happens it spells the end for your motor as it begins to overheat any time you place it under load. That’s when you take it to the shop and hear those dreaded words. It’s the Land Rover equivalent of a bad result on an AIDS test.

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