Exceptional or Ordinary? You decide . . .

How do you solve math problems in your head? Perhaps a better question is, do you solve math problems in your head? With the availability of electronic devices to do it for us, I would not be surprised to learn that many people never try.

I was reading Darold Treffert’s book on savants, and I was intrigued by a few examples of savant thinking. I tried solving some of the problems in his book to get a feel for how “comprehensible” they might be to me, with no recent practice calculating. Here is a simple example:

You have a carriage with a wheel that’s six yards in circumference.How many revolutions will the wheel make while traveling two hundred twenty miles?

This is how I answer that question in my head. I’d be interested in how you might do it:

Six yards is eighteen feet. I see that as a short line.

So one hundred revolutions of a six yard wheel would take me 1,800 feet. That’s a much longer line in my head, one that curves.

Three hundred revolutions would take me 5,400 feet – more than a mile. Now the line has curved back unto itself, making a circle.

How many rotations are there to a mile? Less than three hundred. A mile is a smaller circle. I can see those circles, on inside the other.They do not quite match.

I adjust the length of the longer line that forms the big circle. Try 290 . . . that’s 5,400 less 180, or 5,220. A mile is 5,280. Now I see the line laid flat, like a straight stretch of highway. Two hundred ninety revolutions leaves us sixty feet short of a mile marker. So what’s the fraction?

Three eighteens go into that sixty-foot remainder with the same six remainder. Adding that to the 290, I see the answer is 293 and a third. The six-yard wheel does not fit a one mile line, but it fits perfectly into a three-mile ring. If you put a mark on the wagon wheel, and mark any point where it touches the big circle, those points will touch every time the wheel rolls past. I like that.

If you roll the same wheel around a one-mile ring the points will only touch every third trip around, which is unsettling to me. I like smooth fits, so I will solve the next step using three-mile units.

I can now see the answer: 880 revolutions. A perfect fit. Six yards, three miles, and eight hundred eighty turns.

How many three-mile eight-hundred-eighty revolution units are there in 220 miles? My mind visualizes stacks or piles for this next step.Seventy units reach two hundred ten miles. I quickly see how seventy-three and a third are needed to reach the two-twenty goal.

Stacking seventy-three piles of 880 in my mind takes a little time.Eventually, the stacks add up and I see the result is 64,240. Now I just have to add the third (of 880) and I’m done. To do that, I add three hundred to the pile, making 64,540, and then take back six and two-thirds.

64,533 and 1/3 is the answer to the question.

As a further experiment, I scaled up the distance, to 2450 miles and then 20,315 miles to see if I could keep scaling up the numbers. There must be some limit to that, and it certainly took me longer, but I solved those bigger problems in a few more minutes. Solving the longer distance problems involved one and then two more levels of “stacking” in my mind.

It does not seem that hard to me. I often did similar calculations as a kid, for fun. I’m sure I could do it again, pretty quickly, with some practice.

I test my answer with a calculator. The process to do that is considerably simpler.

I multiply 220 (miles) by 5,280 (feet per mile) to get 1,161,600 – the total distance in feet.

I divide that by 18 (the wheel circumference) to get 64,533.333 – the revolutions turned.

It’s a lot faster to get this answer with a calculator, for sure. But is the ability to figure this out in one’s head really exceptional? In today’s world, I would not be surprised if kids never develop these skills. When I grew up, though, pocket calculators did not yet exist and I had to know how solve problems like this. I suspect many people of my generation could solve a problem like this in their heads, but perhaps I am wrong. What do you say?

Some thoughts on spark plugs

Advances in technology have lengthened the maintenance intervals for many pieces on our cars. One of those pieces – the one I am writing about today – is the spark plug. All gas engine cars have them.

When I started in the car business, it was common for plugs to need cleaning every year, and replacement by 15,000 miles. As technology improved and engines got cleaner, the plugs started lasting longer. First it was 30,000 miles, then 50,000, 60,000 miles.

Today, many of the new cars we service have 100,000-mile spark plugs installed at the factory. That 100,000-mile rating was derived by installing the plugs in test vehicles, and then driving them hard and fast to pile on the miles. At various intervals the plugs were removed and inspected for wear. After a number of engineering tweaks, Bosch, Beru, NGK, and other spark plug manufacturers came up with a plug that would last the 100,000 miles and still perform acceptably. Based on that, the carmakers established the current change interval for spark plugs.

So the question today is: How often should you change your plugs, if you have a car with the 100,000-mile change interval? Should you follow the manufacturer’s recommendation, or do something else? Why?

The first thing I point out to new clients when we discuss maintenance is that there is a time component to service as well. Spark plugs may hold up fine for 100,000 miles if driven on the highway every day, but short trips and occasional use will wear them out a lot faster. A person who drives 10-12,000 miles per year may not hit 100,000 miles for almost ten years. That’s way to long to leave a set of plugs in the car.

Carmakers recognize that. If you look in most owners manuals you will see a time specification for plugs. They’ll say something like five years or 100,000 miles. I strongly suggest you pay attention to this time limit when considering long-life wear items like spark plugs.

I have read of spark plugs breaking off in the cylinder head when removed after many years. I’ve never experienced that on a five year old car, but there may well be parts of the world where corrosion is worse (near the ocean, as an example) and it you live in such a place, you’d be wise to consider that fact and adjust your service intervals accordingly.

When changing plugs, the next decision a motorist faces is what plug to buy. If you are at the dealer, the decision is simple: you’ll get original equipment plugs. If you’re at a Bosch Car Care Center, you should get the correct Bosch plugs, and if you’re at an independent or chain store, you best find out what they propose to install to be sure you are comfortable.

Thirty years ago, selection of spark plugs was simple. A dozen part numbers would service a majority of the cars on the road. Today many cars have special plugs and it’s important to install the right one. Every parts store has cross-reference catalogs, all of which lead you to believe any “crossover” plug will work. In my experience, that’s often true for older cars but often wrong on newer vehicles. We’ve seen Land Rover, Mercedes, and BMW cars with ignition misfires that were ultimately traced to “supposedly correct” but off-brand spark plugs.

If you have a late model car, be sure you fit the right plugs.

The last point I’d like to address with spark plugs is what happens if you don’t change them in time. As plugs age, the voltage to fire them increases. A plug that needs 20,000 volts to fire when new may need 80,000 by the time it’s used up. If you go beyond that, the voltage may rise to 100,000 volts or higher. This increased voltage puts much greater stress on ignition coils and wires. Premature ignition failure is the usual result of running plugs too long.

Six spark plugs might cost $80 for your BMW or Mercedes. Six spark plugs and six coils (because you waited too long) could cost $700, maybe more. As you can see, changing plugs before the ignition fails makes very good economic sense!

Electronic Module failures

We are seeing a disturbing trend with many high end cars built in the 1980s and 1990s. Their auxiliary control modules are failing, and replacement parts are not available. You can still buy engine control modules for Jaguar, Land Rover, and Rolls Royce cars, but many of the other electronics have been discontinued.

We can fix some issues on these controllers, but one thing we can't fix is extensive corrosion damage from failure of the "permanent" backup batteries many of these modules carry inside.

If you have a collectible European car, and it's 12-15 years old, it's time to pull the modules apart and address this issue BEFORE you have irreparable damage. As much as it may cost to fix something that's not broke, it will cost way more once it is broke . . .

Supercharged Sports that suddenly stop charging

A few weeks ago, I had a strange and curious experience with a Range Rover. It started with a simple warning light, and the usual request. “Can you reset my check engine light so I can get a sticker?”

Why do so many people think these lights come on just so they can be reset?

What possible purpose would that serve?

I explained that we’d have see what fault codes were stored, at which time we could decide what to do about them. In most cases, when you see a check engine light, you need a repair, not a reset. Codes mean many different things. Sometimes, they point to specific repairs. For example, a “replace Thelman wire” code is self-explanatory. You replace the Thelman wire. Other times, codes are more vague. “Fuel mixture out of range” can mean most anything, from air leaks to snoot problems.

This particular car had a code for inoperative cam adjusters, which was strange, because Supercharged Sports don’t have cam adjusters at all. We cleared it, and it came back right away. We looked closer at the engine, to make sure it had not grown cam adjusters on its own. It hadn’t.

Every now and then, mechanics run into situations like these . . . codes that don’t make any sense at all, yet will not go away. When that happens here, we look to see if a software update will fix the car. We use our test system to get the software version and we compare that to the latest version Land Rover lists for that particular vehicle. If there’s newer software, we install it. When we tried that, we found something even stranger.

The vehicle had software for a non-supercharged Sport installed, and the computer was telling us it had never been re-programmed. Either the car had been running around for four years with wrong software, or the computer was lying. Which was it?

After some interrogation of the motorist associated with this particular vehicle, we concluded that the software was probably original. How they made it through four years of operation, only complaining about a check engine lamp now, remained a mystery.

We downloaded new and correct software, and the problem vanished. The cam adjuster faults disappeared, and all tests were normal. We felt great pride in a job well done, and handed the vehicle back to its owner. Unfortunately, this particular Sport did not stay fixed.

“My car was in the passing lane, doing 70, when it lost all power and the check engine light came on. I coasted to a stop, shut it off, and started it again, and it was normal. That’s happened every time I drive to New Haven, and I’m getting scared to take my truck on the highway. What’s up?”

Did the car have an aversion to New Haven? I’ve seen such things before. “Bring it in,” I said, and we’ll see what the codes tell us. A check revealed a P2601 code, which points to a failure of the pump that moves water through the supercharger when you get on the throttle. His seemed to be failing. But why now?

A check of Land Rover service bulletins held the answer:

Land Rover Technical Service Bulletin #LTB00041, Rev 2

Reduced Power Under Load

Possible DTC P0096 and/or P2601 Stored

AFFECTED VEHICLE RANGE:

Range Rover (LM) Supercharged 6A198058 to 7A261419

Range Rover Sport (LS) Supercharged 6A901924 to 7A109767

CONDITION SUMMARY:

REDUCED POWER OR MISFIRE AT HIGH ENGINE LOADS

Situation: The customer may complain of reduced power and or a misfire at high engine loads and road speeds, with the possibility of Diagnostic Trouble Codes (DTC) P0096 and/or P2601 stored. The electrical harness power supply and ground for the auxiliary coolant pump may be cross connected in connector C3006. The pump will run backwards causing the Engine Control Module (ECM) to reduce power to prevent damage because the pump flow is low. The auxiliary coolant pump will be degraded under these conditions.

Action: Should a customer express concern, modify the wiring at connector C3006 to the correct positions and install a new supercharger coolant pump as part of the repair if either the fault codes or the incorrect wiring is discovered following the Repair Procedure outlined below.

We checked, and this fellow’s car did indeed have the reversed wiring. A swap of the wires and a new pump, and he was on his way.

How does this situation come to pass? I spoke to Tony Gill, who heads Land Rover tech support at Autologic in the UK. He suggested a few possible answers.

This car seemed to have the wrong software put in at the factory, As a result, it may have never tried to use the auxiliary pump because the engine controller didn’t know it was there. Non-supercharged Rovers don’t have this pump. Of course, that does not explain how this truck went four years looking for cam adjusters that were never there . . .

It’s also possible that the pump was strong enough to push coolant through the supercharger backwards, against the flow of the regular water pump. It may have done that for all this time, and finally decided to fail.

We may never know the full answer, but it does appear to be fixed.

The moral of this story . . . check your software. Even in new vehicles, mistakes happen. And some of them take a long time to find. It’s shocking to me that there are four-year-old vehicles out there with wiring that was backwards from Day One, but it’s indisputably true.

That is the wonder and magic of British Motorcars.

Rolls Royce in the 2010 Basketball Hall of Fame parade

Sports fans know Springfield as the home of the Basketball Hall of Fame. Each year, a new class of players and coaches is inducted in a nationally televised ceremony. The biggest event is the induction itself, and I'm always pleased that Robison Service plays a role.

For the last nine years, we have organized the parade that brings the inductees and their families to the red carpet in front of Symphony Hall. We've always called the parade a Rolls Royce parade in honor of Rolls Royce, who built cars here in our city in the 1920s. As you will see, for this year's parade, we added a few Mercedes and a Jaguar drophead to the mix.

Watch the 2010 video here

The Porsches come out in the spring

Meet Dave Tassinari, my neighbor here on Page Boulevard.



Seven years ago we sold Dave a tired old 928. "I'm going to take it apart and build a race car," he said. This is the result . ..




As you can see, he's put a huge amount of work into this project, and the results speak for themselves.





This weekend Dave is off to his first track event. Good luck out there!

The last word on Land Rover liner failures - I hope!

Note:  This story was written a few years ago, but it's even more true today.  Robison Service is building 4.0, 4.6, and oversize Land Rover engines using the latest flanged liner technology.  Call us at 413-785-1665 or write robisosn at robisonservice.com if you'd like to talk about YOUR engine project.

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I have written several articles over the years, describing the liner problems in Land Rover V8 engines. No matter what I write, the damn engines continue to fail. And we’re seeing more and more of a pattern. These engines are, as best I can tell, failing more frequently than before, especially in the last of the Discovery II rigs. Where earlier motors tended to fail on end cylinders, these motors are blowing out the middle cylinders. That led us to wonder . . . is there a new problem in these late engines?

Last week we decided to find out.

We just got a new CO2 laser up here, and our machinist Steve Dutcher was looking for some action on a lazy Friday afternoon. Some people would go fishing, or even weasel hunting, but Steve had other ideas. He cut a Land Rover engine block in half, just because it was there.

When he did, we finally got some hard answers to what’s going wrong in these motors.

Let’s begin by looking at a brand new Land Rover short block. You might call this the “pre-failure” picture:



In this shot you see the aluminum block, with steel liners, and aluminum pistons. As you can see, the steel liners are tapered at the top, sort of like you’d bore a countersink hole if the engine block were a piece of wood. . . .



Now lets jump to the late model block Steve cut in half. He removed the liners before cutting this block right through the middle of the third cylinder bank. Check it out:



This block had a middle cylinder failure. There was no visible problem with the liner but it failed a pressure test on the middle cylinder. When we took the liner out, we found the crack you see circled here. Take note of what a subtle defect this is . . . you can barely even see the crack, but it’s enough to kill the motor. Here’s a closeup of the 1/4 inch crack that cooked this block.



The block cracked from the liner wall into the coolant jacket from the stress of the head bolt. Here’s a shot of the deck that shows that relationship. In fact, if you look close, you can see how the depth of the crack corresponds to the depth the head bolt is threaded into.



Here's a closer view, with my finger for perspective. The blue circled crack is visible to the left of my fingernail



Here’s another interesting shot. In this image you can see the step that prevents the liner from sliding down into the crankcase on these newer motors. In this design, the liner can’t actually move more than a few thousandths of an inch unless they failed to seat it against the step at the factory. What does that mean? It means the stories of "slipped liners" in these newer engines are probably incorrect. The issue is not movement of the liner (which can't happen in this example) but a failure of the block wall behind the liner.



This shot shows that post-2000 model year liners can’t move very much at all but the engines fail anyway. What gives? A little bit of thought gave us some answers.

The liner is tapered at the top where it meets the head and head gasket. For that reason there is no gas or pressure tight seal between the liner and the block. Therefore, when the cylinder fires, some combustion gas gets behind the liner. If there’s a crack back there, out it goes and you know what happens next.

Your coolant gets displaced by superhot combustion gases, the engine temperature skyrockets, and in the blink of an eye, your Rover is assuming the British Position on the back of a tow truck. And you are facing a ten thousand dollar repair bill.

How do these failures happen? It sure looks like the stress from the head bolts is causing the blocks to crack. I don’t know why this is happening now; the aluminum may be more brittle, or the head bolts may be stiffer. Perhaps longer or shorter bolts would help.

Now that we know what’s happening, it’s clear that top hat liners will fix this problem once and for all, even in an engine with cracks in the aluminum. The flanges on top of the liner will seal tight against the head gasket, preventing any combustion gas from getting between the liner and the block and blowing things up.

This picture shows the difference. The left cylinder has the original liner. The right cylinder has a top hat liner, which cannot move in the block. In addition, the head gasket now seals against the liner for a firmer and more positive combustion seal.



Why doesn’t Land Rover use flanged liners? My guess is, they cost a few dollars more and carmakers are notoriously cheap. It’s also possible that there’s an issue with the steel liner expanding at a different rate than the aluminum block and heads.

How about the engines that rap at idle? I’ve had several late model Discos at the shop with noise complaints. In two cases, dealers told the drivers they had noise from liners moving up and down, and they suggested the motor was about to fail as a result. One dealer actually got the motor hot and heard it rap, at which time he sprayed the side of the block with a hose and the rap went away. He told the customer that was evidence of liner movement.

Actually, it wasn’t. These photos make it pretty clear that late model liners have nowhere to move. The hose test simply showed that the noise went away when the engine block was cooled – in other words, the noise was triggered by thermal expansion.

Steve and I sorted that noise question out on another engine a few months back. On that motor – which had exactly the same hot rap – we found the piston skirts had collapsed in about ten thousandths of an inch. That was enough to make them rock when they got hot, and they rapped good and loud.

On that engine we expanded the piston skirts and refitted the pistons. No more rap. But did that repair need to be done? Loose piston skirts would not lead to a failure. I’ll bet that motor would have run 25,000 miles with that rap, maybe a lot longer. In any case, new pistons are the fix. Liners are not involved at all, unless the block were to crack when the head bolts were cinched down one more time . . .

While were talking noises . . we saw a few engines whose secondary air valves had failed, and they also rapped. If you didn't know better you'd swear that secondardy air rap was coming from within the motor. And we still see engines with rocker shaft issues and lifter issues where the raps will fade in and out as the parts rotate while the engine idles hot.

I’m glad we’ve finally got some positive answers about these latest failures. When we rebuild engines here, I’m thinking we need to do flanged liners in the middle cylinders, and maybe all eight cylinders. The only drawback to that is going to be cost – it’s going to make the cost of redoing an old block almost as much as the $5,000 cost of a new one. But if the flanged liners last and the factory ones fail, that’s still smart money.

Like everything else, time will tell . . .

And one more thing before I go. In October I wrote about some later blocks that failed from premature corrosion. Here's a view of the freeze plugs on this motor. As you can see, they are pretty rotted but the aluminum block itself is good. Check your freeze plugs if you do an overhaul. It would suck to lose it all for a two dollar metal disc.