High mileage engines

Author
Discussion

Sensei Rob

Original Poster:

312 posts

79 months

Saturday 12th June 2021
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Hi guys,

Occasionally, you hear about cars that have done a million miles and sometimes you hear talk of particular engines being durable.

What I can't get my head around is what makes an engine more durable than another one? How would an iron block engine be more durable than an aluminium one? I get they can handle bigger pressures, but surely they've been designed to handle a specific power output, so if they only ever operate to within those power figures, it wouldn't make a difference whether the block is aluminium or iron?

Or is it just a case of other stuff on the car failing before the engine? As in, an otherwise healthy engine being hampered by being stuck in a car which has a whole heap of other issues deeming the car to be scrapped/abandoned.

ARHarh

3,755 posts

107 months

Saturday 12th June 2021
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Maintenance will make by far the biggest difference.

gazza285

9,810 posts

208 months

Saturday 12th June 2021
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Coefficient of thermal expansion? Cast iron's coefficient is half that of most aluminium alloys, which puts gaskets under less shear force.

TyrannosauRoss Lex

35,070 posts

212 months

Saturday 12th June 2021
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Depends on the engine and the car it's put in. It isn't necessarily the fact it's aluminium or iron it's the overall design of the engine. Many factors play a role, tolerances to manufacturing/design, design in general. Some old cast iron engines were shot well before 100k miles, some aluminium engines last many hundreds of thousands of miles.

I think these days other issues mean the car is scrapped before the engine, but you do hear of timing chains snapping or whatever. I think keeping on top of the servicing is, of course, very important.

steveo3002

10,521 posts

174 months

Saturday 12th June 2021
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bet the ones that have done massive miles have been running all day /night so way less cold starts

samoht

5,712 posts

146 months

Saturday 12th June 2021
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I don't think the block material itself is that significant, aluminium blocks will be made thicker to have the required strength.

There are certain areas where things tend to go wrong that can write off an engine, e.g.:
- timing belt/chain
- bottom end bearings
- valvegear
- head gaskets / overheating
- injectors / fuel system

Certain engines have certain specific weaknesses in particular areas which often lead to a premature demise. Otherwise it's mainly a question of maintenance, if you keep looking after an engine it will generally keep working indefinitely I think.

brisel

873 posts

208 months

Saturday 12th June 2021
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How they are used and maintained will alter their lifespan. A thrashed chavmobile that the driver has modified and bounces off the rev limiter on a daily basis won't compete with a high miler that has sat at the speed limit on motorways on long journeys for much of its life, though the long oil change intervals designed to please fleet operators don't help. A shopping trolley that never gets warmed up properly won't be a good buy either, even if garaged and serviced regularly.

MarJay

2,173 posts

175 months

Saturday 12th June 2021
quotequote all
Tolerances, quality of castings, quality of machining, quality of materials, quality of material treatment... The list is endless.

To be honest with most cars, the engine is not the worry. With most cars it's actually structural rust, suspension components, brake components etc that wear far before the engine does. When an engine does let go, it's either got a design flaw, was poorly made or was messed with in some way.

Earthdweller

13,548 posts

126 months

Saturday 12th June 2021
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steveo3002 said:
bet the ones that have done massive miles have been running all day /night so way less cold starts
We’d regularly out 250k on cars in four years at work .. serviced pretty much every month and no expense spared

But very reliable

DailyHack

3,173 posts

111 months

Saturday 12th June 2021
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No secret really, regular maintenance is the key, not this 20k+ regime people get suckered into.

mph999

2,714 posts

220 months

Saturday 12th June 2021
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Change the oil every 5000 miles

Don1

15,945 posts

208 months

Saturday 12th June 2021
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IIRC, BMW actively sort out 4 cylinder engine blocks for their F1 programme. Why? All the imperfections had been worked out, thus allowing stupid levels of boost.

Thus if looked after, no issues.

NGRhodes

1,291 posts

72 months

Sunday 13th June 2021
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mph999 said:
Change the oil every 5000 miles
No need.
Modern oils are very good, I've seen many used oil analysis and looked at quite a few studies.
One example I know of someone with a early 90s Saab turbo who does the occasional used oil analysis, 450000 miles on the clock, commutes 700 or so miles a week at an average of over 100mph between Munich and Berlin, last oil change done at 19000 miles using Shell Ultra 0w-30 (car specifies 10w40 and changing oil 7500 miles) Oil still had a few thousand miles of life left, still within specified viscosity and no excess metals (from wear) in the sample.

NMNeil

5,860 posts

50 months

Sunday 13th June 2021
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steveo3002 said:
bet the ones that have done massive miles have been running all day /night so way less cold starts
I used to do the emissions testing on the Las Vegas Checker Cabs. Mostly Crown Vics and all with very, very high mileage, but as you say they ran almost 24/7, and I never had a single one fail it's smog test.

wiliferus

4,060 posts

198 months

Sunday 13th June 2021
quotequote all
samoht said:
I don't think the block material itself is that significant, aluminium blocks will be made thicker to have the required strength.

There are certain areas where things tend to go wrong that can write off an engine, e.g.:
- timing belt/chain
- bottom end bearings
- valvegear
- head gaskets / overheating
- injectors / fuel system

Certain engines have certain specific weaknesses in particular areas which often lead to a premature demise. Otherwise it's mainly a question of maintenance, if you keep looking after an engine it will generally keep working indefinitely I think.
This all day long. Engines rarely die due to the block failing. It’s the ancillaries around the block that fail. As with all cars, maintenance is key, and then it becomes as owner decision as the miles rack up how much money they’re willing to spend to keep it going when something breaks.
My Volvo D5 has 192k on the clock. The D5 is renowned for generally living forever. However, the car itself is worth buttons. A large bill, maybe fuel rail, fuel pump, bearings would probably see the car either off to the scrap yard or to someone who’s willing to take the expense on.

aka_kerrly

12,418 posts

210 months

Sunday 13th June 2021
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I'd say it all comes down to maintenance and fixing issues immediately will likely lead to a long life.

Nearly every engine that I've come across that has failed dramatically has had existing issues which have been ignored, usually oil/coolant leaks which cause an engine to overheat or worse seize.

The only other reason I've seen engines destroy themselves is when they are being forced to work outside of their original design parameters, usually people who have fitted turbos to NA engines or people with turbo engines who have ramped the boost up significantly whilst not addressing the fueling/cooling requirements.





jeremyh1

1,358 posts

127 months

Sunday 13th June 2021
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I have always got big miles out of engines

54 Mercedes Sprinter
53 Iveco Daily Both went just over 400 thousand miles

2 53 plate Citreon C15 vans 370K and 290K all same boxes and engines

I have a 56 plate Pug Partner at the moment with 200K

As things have got more complicated I now have leased vans and they will probably blow up at midnight when the warranty runs out !

An engine will last if it is manufactured well in the first place . Then regular oil changes I do around 6 K with a good quality oil . Another thing I do is check the gear box oil level every 6 or 8 weeks . You might save the gear box as well .

My list of good engines with a good chance of high miles
Toyota d4Ds
Mercedes early 2000 and 90s
French diesel engines the old 1.8 the 1.9 (the best onee) 2.0 HDI

At the moment I know of two high mileage vans still working
10 plate Merc Sprinter curtain sider in Plymouth with 470k
and another Sprinter in Holland with 800 K ( Killiometers) 2005 one Still doing distance Euro work all the continent

ExPat2B

2,157 posts

200 months

Sunday 13th June 2021
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People worry too much about the oily rotating bits. A properly maintained engine actually floats every friction point on a layer of oil and there is next to no actual contact or wear once the engine is up to temp. Almost every dead engine ( with the notable exception of Alfa ) I have seen has been taken out by failure of an ancillary like a snapped belt/chain or water pump/ headgasket.

Most car engines will do 300,000 to 500,000 miles easily with only the top end needing adjustment.

This is good example to all the things that will wear out on a car and end an as uneconomical repair.

https://www.youtube.com/watch?v=svwkTilB7cM

BroadsRS6

785 posts

39 months

Sunday 13th June 2021
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A NYC taxi we got at Times Square in 2019 had 176,000 miles on the clock and bearing in mind most of that work will be 20 mph and under with zillions of stop starts, that's impressive in my book.

finishing touch

809 posts

167 months

Sunday 13th June 2021
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The piston rings don't run against the aluminium bore.

There's a steel liner inserted into the block which will be made from a high quality alloy steel far superior to cast iron.

Often these are "wet liners" and can be removed if needed. My 907 Lotus engine ( in my Seven ) has wet liners and was made in the seventies.



Don't you lot no nuffin ? hehehehe

Paul G