On Sat, 02 Aug 2008 03:28:26 +0000, Christopher Tidy
wrote:

Hi folks,

This question came into my head a few days ago. I often hear people
suggesting that the latest vehicle engines last longer and are more
trouble-free than older engines. But I also hear people saying, just as
often, "They don't make them like they used to".

I was looking at a Dennis Z Type lawnmower a few days ago. I am hoping
to acquire one. For those who don't know, this is a legendary machine. I
think its engine is probably the best lawnmower engine ever made. It has
forced lubrication and an oil filter, complete with a passage for oil
through the crankshaft, and was introduced in 1922.

Now it's possible that one might look back at older products and view
them as being superior because all the poor quality products from the
era wore out and were replaced. It's also likely that the answer to the
question will depend on the type of engine you look at, and the quality
of construction. But I'll leave it as a general question, as I'm
interested to hear anyone's experience.

I get the impression that perhaps engine technology is moving in two
opposing directions. On the one hand, improving technology such as
better lubricants, filtration and bearing materials, are resulting in
components lasting longer. But on the other hand, the whole industry
appears to be moving towards less maintainable engines. Engines which
are wholly dependent on electronics, sometimes with coated rather than
lined cylinders. Engines which are difficult for anyone to maintain at
home. Perhaps this is why I don't hear people talk about replacing
piston rings, or having crankshafts regound anymore? Or perhaps these
parts last for the lifetime of the vehicle?

I'd be interested to hear people's opinions. I'd also be very interested
to see data comparing wear rates in modern and old engines, if anyone
knows where I can find such data.

Best wishes,

Chris Tidy

I ran two little 72cc Honda 4 stroke motorcycles for years. (one
replaced the other) both ran for 15,000 to 17,000 miles and were run
at 6,000 rpm at top speeds of 60km/hr in traffic. They got necessary
servicing and were utterly reliable.

these were replaced by a kawasaki BR250 that I ran for 10 years.
it developed an incredible engine vibration so I had it torn down and
the problem resolved and rebuilt. it turned out that one of the main
ball bearing cages has broken up.
I got a "you've gotta come and see this" call from the guy doing the
work. at 80,000km I think, the honing marks werent even scuffed on
the cylinder bore, there was no corrosion anywhere in the galleries of
the engine, in short once the faulty parts were replaced the engine
went back together in new condition.
the BR has gone through a number of owners since I sold it, the
current owner has it in pride of place in his lounge as a classic
bike.

I rate the hondas as little engines. I flogged the daylights out of
them and never once did they cause me problems.

engines since the 70's have been absolutley reliable if you service
them.

btw Hyundai has an engine in the excel which is embossed on the engine
as suitable for 150,000km without adjustment. that says something.

I'm sure it is in the metallurgy and the QA. but yes my experience is
that my engines have lasted far far longer than my fathers.
Stealth Pilot