Repairing a 1979-2002 V8 engine with a dropped linerWhat’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.
The traditional cure for this problem has been the installation of a brand new short block — a new block fitted with pistons, rods, and crank. A few years ago when new blocks were available for $1,300 this was the way to go. But today the price of new short blocks exceeds $4,000 for some models and the total cost of repair can easily exceed $9,000. Clearly, a less costly alternative is welcome.
For many years our shop had been repairing liner problems with Rolls Royce, Bentley, Jaguar, and Ferrari engines. We are now doing the same with Land Rover motors. We didn’t repair Land Rover motors until recently because the cost of replacement blocks was low. But that situation has changed. So, without any further ado, here is how we fix a liner problem.
The engine is stripped to its component parts and everything is cleaned. If the engine has sludge from not changing the oil we’ll clean it up here. We look carefully at the fit of the liners in the block. You can often (but not always) see a dropped liner even though they are seldom loose enough to move by hand.
Next, we use flatness gauges to make sure all the precision flat surfaces of the block are really straight and flat. If they aren’t we machine them till they are. If the mating surface between the block and head is not perfectly flat you’ll have fluid leaks or other problems. We then bolt plates over the tops of both cylinder decks and plug the oil and coolant holes down below. We fill the oil and coolant passages with high pressure compressed air to check for leakage. Some leaks can’t be easily seen and this method allows us to find them.
The pressure test also helps find cracks in the aluminum casting, which we then repair. We also use chemical tests to find cracks. Cracks can appear anywhere stresses are high, and repair now can prevent catastrophic failure later.
The failed liners are then extracted from the block in much the same way as a dentist extracts a tooth from your mouth, but the blocks seldom yell or squirm afterwards. We do strap the block securely to a table before extraction, just like a dental patient. Blocks do not bleed like people afterward because we’ve removed the fluids first in the cleaning process.
We bore the aluminum block a little larger and press in a slightly oversize liner, which we bore to size. We measure the pistons and fit new ones if needed. Otherwise we install the old ones with fresh rings. Most of the time, we’ll install new main and rod bearings. If the engine had sludge damage there’s a good change we’ll need to grind the crank to repair the excessive wear. We clean up or rebuild the rods, rebalance the motor, and it’s good as new.
The other bits and pieces of the engine are cleaned and serviced and the whole thing is put back together and put back in the vehicle. The cost of a repair like this is usually considerably less than the cost of a brand new short block. There are more dentists than automotive machinists in most phone books, but if you look around you should be able to find someone with the skills to do this wherever you live. The process I describe is used on many other motors so a skilled machinist should be able to do a Land Rover block as well as a GMC engine in a bus.
Kind of makes you wonder why the same dentists that do people don’t do horses and dogs, doesn’t it? But that’s a topic for another article.
Now, the part you’ve all been waiting for — prevention. How can you keep this from happening to you?
Well, the answer is simple. Keep your motor cool. How cool is cool? 190 degrees, that’s how cool is cool. Your thermostat opens at about 180 degrees. The engine needs to be that warm to run efficiently. The cooling system should be able to keep it from getting any hotter in almost any weather. If your temp gauge rises it’s time to take action – before you cook a liner and turn a $600 cooling system job into a $6,000 engine job.
At 100,000 miles, radiators are usually clogged and they should be re-cored or replaced. Cooling fan clutches wear out and electric fans fail. Make sure these things work on your truck. Also make sure the system is full of coolant of the correct type. Mixing the traditional green coolant with the newer orange Dex-cool products can lead to formation of sediment and other bad things. So make sure that doesn’t happen in your motor.
Once a Rover is past the initial break-in, liners almost never fail unless there is an overheating incident. So the answer is simple: no overheating = no liner failure.
Before I go, I’d like to tell you about some books I’ve been reading and pictures I’ve been taking…
Working in the Wild — Land Rover’s manual for Africa, is Land Rover’s official guide to operating their vehicles in primitive places. It’s full of practical advice that might get you home from some remote place one day. Buy your copy now, because if the American product liability lawyers see the common sense advice in this book it will vanish in the blink of an eye.
Topics in this book include selecting the right Defender for the job; compiling and maintaining a stock of spare parts; driver training; emergency repairs; fact about fuel; building a workshop in the wild; selecting the right accessories; and a final section entitled… what if?
Mozart in the Jungle, from oboist Blair Tindall, is a colorful look at the seamier side of the classical music world. It’s not the conservative, staid, respectable place you may imagine. It’s a lot livelier, and if my own experience is a guide the reality is even wilder than the book. Some of you are aware that I was in the music business before I was taken up with Land Rovers, although I was into electric music, not classical. If you liked my brother’s books you’ll probably like this one too.
Inequality Matters — the growing economic divide in America provides some new insights into our vanishing middle class, how we got that way, and what we can do about it. This book is a series of essays by well known authors that was compiled by Demos, a New York based think tank that studies social policy in America.
And finally, for those diehard Robison fans… I have put a public gallery of my photos online at pbase.com/robisonphoto Feel free to check it out and leave comments or reactions. I’m going to try and add a new picture every day to keep it interesting.