Taking an Older Car on a Road Trip – Part 2

Yesterday, I talked a bit about the things that will sideline you on a road trip – and probably ruin the trip. By the time you find a place to look at the car, have it towed, order the part (in all probability), find a motel, you will have spent 2-3 days. Maybe more.

And many times the car will give you warning of an impending failure – sometimes for months. Particularly for a bearing on its way out – coolant pumps, idler pulley bearings, and alternators will (usually) squeak before they fail.

Most of the time.

Anyway, there’s a couple of more things that can fail on the road and leave you stranded. One of them can destroy your engine.

Timing Belts

Your car needs something to turn the valves – exhaust and intake, in sync with the pistons that are moving and turning the crankshaft.

One video is worth a lot of words and you can see the relationship better here…

The way the engineers design this is to use either a timing chain, a belt, or gears. The gears are pretty rare, but my 74 Capri with the Ford V6 used them.

Belts started to become popular in the 1970s and were used extensively until recently.  Toyotas and Hondas used them almost exclusively. I think Volkswagen used them. GM and Ford used both although I believe their V8 engines used chains. Most of their engines were – and are – chains.

Mercedes and BMW always used chains.

Belts seem to be on the way out today.

Personally with the maintenance required to change the belts, I never understood the appeal of them from an engineering side. My mother had a Lexus V8 with a belt, and the major service was way over $1000 – 15 years ago. The front of the engine had to be removed to get access to the belt.

Belts run quieter, need no lubrication system to keep them oiled, and are simpler. But they all have a change interval, and if not adhered to, can break.

And if they break, it can be bad to catastrophic for your engine.

The car in any event will immediately stop. The intake and exhaust valves stop working.

If the engineers designed the engine to be non-interference, the pistons will never hit the valves with the failure. The shop just has to realign the timing of the valves to the pistons and install a new belt.

If the engine is an interference design, you can have problems. You will almost always have damage when the valves hit the pistons. In the worst case you have ruined the engine.

I have seen recommended change intervals anywhere from 15,000 miles (a Ferrari Testarossa from the 80s) to 90,000 miles.

Check your manual, if you have a belt.

I always wondered why (until recently) an 80s Testarossa wasn’t all that expensive and for the age, many had a very low mileage. I thought that if I had a car like that, it would be driven every day.

About 15-20 years ago a neighbor of mine was a mechanic for an independent shop that serviced Italian exotics.

So I had to ask him how much a major service was on a Testarossa. I know, if you have to ask…

$8,500 was the reply.

And this was 15-20 years ago!

They have to remove the engine. Apparently Ferrari recommends a 15,000 timing belt change interval. Every 15,000 miles a major service requiring the engine to be removed.

Taking an Older Car on a Road Trip - Part 2A

A Ferrari Testarossa engine. 12 cylinders, horizontally opposed. Each sprocket you see off the belts controls 1 camshaft. There are 2 intake cams and 2 exhaust cams. The sound of this engine? Bellissimo! Having to pull the engine out every 15,000 miles and change this? Not so much. This is an interference engine, meaning if a belt breaks you have a lot of damage.

If designed properly, a timing chain, with regular oil changes, should last the life of the engine. And if they do fail, many times it isn’t the fault of the chain itself but a chain tensioner (oil fed; they keep the chain tight so it doesn’t slip off the sprocket teeth), or a chain guide.

It took Porsche 20 years to design a trouble-free chain tensioner for its air cooled flat 6 engines powering the 911. If you are shopping for one of these cars you want to make sure, if it is before a 1984, that it has had the “Carrera Tensioners”.

A Mercedes V8 (M116) from the 80s had a problem of a chain guide breaking (made of a teflon-like material) and getting carried up by the chain to the sprocket.

Rarely is the chain itself the problem.

So, if you don’t know when your timing belt was changed, best to replace it. And while you are at it, replace the belt tensioner too.

Alternator Brushes

These aren’t brushes like “paint brushes” but 2 metallic strips that are spring loaded for pressure, and ride on the copper commutator. On my older Mercedes the Bosch alternators have had a neat feature. These brushes are replaceable with 2 or 3 screws on the back of the alternator. You do not have to disassemble the alternator and sometimes (depending on model) you don’t even have to remove it from the drive belt.

With the miles, these brushes wear down. The springs are pushing them against the spinning copper commutator. When they get worn enough, the alternator isn’t generating the electricity the engine electrical system needs. You won’t stop dead, but the car will be running just off the battery, and it will be depleting. Hopefully you can get to a shop before the car dies.

Since the Bosch alternator brushes  are so easy to update, I have just replaced these at 150,000 miles. After 2 sets of brushes, 300,000 miles, the commutator has a groove from the brushes that is so deep as to render a 3rd set unusable. Then it is time for another alternator – after 300,000 miles!

Maybe your car has a Bosch alternator – these days with the global market, auto makers shop the world for their parts. Maybe if  your alternator isn’t a Bosch it might still have this feature – use it!

If it doesn’t I would at least ask some people who might know – a service writer, shop mechanic, how many miles you can expect from your alternator before you set sail on a trip.

Taking an Older Car on a Road Trip - Part 2C

The old Bosch brush assembly from my SL500. The brushes had about 150,000 miles, and were still usable. They are about half the length from new. I changed it for piece of mind – the part was maybe $40.


Taking an Older Car on a Road Trip - Part 2D

The new assembly installed on the SL’s alternator. This assembly, in addition to the brushes, has a new voltage regulator (in back). You can see how the springs put pressure on the brushes that pushed against the copper commutator. You can also see the groove forming on the commutator.

Part 1 is here.


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2 responses to “Taking an Older Car on a Road Trip – Part 2

  1. Pingback: Taking an Older Car on a Road Trip – Part 1 | The Lexicans

  2. Pingback: Check Engine Light | The Lexicans

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