Air cooled

[bezzabsa]

OK so why was air cooling dropped???? worked out well for the 2CV, Fiat 126 even pork 911's..

heard mention of emissions , but I would have thought that with modern Fuel injection that could be overcome quite easily...

In the era of its broke - plug it in... I think air cooled would at least remove some of the hassle of owning a modern..

 

Forts pleeeez

[garethj]

Long time aircooled botherer here, 6 VWs, 2 Tatras and some motorbikes.  As emissions get stricter, controlling the cylinder head temperature gets more important, you really need them all to be the same and stable over time so the combustion is just the size it should be.

Take the head temperature across an aircooled engine and they’re all over the place.  Not bad enough to cause a problem with it running but calibration for emissions is impossible.

A shame though, the noise of an aircooled V8 through a throaty exhaust with the fan beating the shit out of the air is bloody lovely.

[RoverFolkUs]

If you think of it, a lot of modern engines now have about 25 thermostats and 7 electric water pumps (ok, slight exaggeration 😅) to precisely control the temperature of certain engine zones just to meet the highest possible efficiency/low emissions criteria. With that in mind it's no wonder that air cooled engines were left behind with the times 

They're great in many ways, just not that efficient which is quite important nowadays!

[grogee]

1 hour ago, garethj said:

the noise of a Beetle popping and wheezing along is bloody excruciating 

FTFY

[bigstraight6]

51 minutes ago, RoverFolkUs said:

If you think of it, a lot of modern engines now have about 25 thermostats and 7 electric water pumps (ok, slight exaggeration 😅) to precisely control the temperature of certain engine zones just to meet the highest possible efficiency/low emissions criteria. With that in mind it's no wonder that air cooled engines were left behind with the times 

They're great in many ways, just not that efficient which is quite important nowadays!

But they just kept on plodding along, in the late 1980’s into the early 1990’s my daily drivers were a succession of cheap VW Beetles, latterly I was commuting daily from Plymouth to Newton Abbot and the old nails did me proud and were simple and easy to keep going.

[goosey]

I think Tatra still offer an Aircooled Diesel Engine as an option in their trucks*

*although I’m probably wrong and my memory is not what it used to be

[Dyslexic Viking]

17 minutes ago, goosey said:

I think Tatra still offer an Aircooled Diesel Engine as an option in their trucks*

*although I’m probably wrong and my memory is not what it used to be

It is possible they do in other markets. Are parts of the world where they don't care about emissions. Have seen agricultural documentaries from South America and combine harvesters from European manufacturers were delivered with older engine technology there. So the same probably applies to trucks.

[AxWomble]

26 minutes ago, bigstraight6 said:

But they just kept on plodding along, in the late 1980’s into the early 1990’s my daily drivers were a succession of cheap VW Beetles, latterly I was commuting daily from Plymouth to Newton Abbot and the old nails did me proud and were simple and easy to keep going.

You’re making the mistake of thinking that car manufacturers want to make products that last. Making it unscathed through the warranty period+2 years is all they need to maintain a reputation for reliability nowadays. Some don’t even manage that and folks will still buy them! 

[richardmorris]

Noise and emissions legislation killed air cooled cars.

I suspect my 2cv will outlive me though.

[Rustybullethole]

Dunno its a funny one. Last few bikes have been aircooled oil boilers. Gs1100 bm and current RE himalayan both running fuel injection and the 18 plate himi is good for ulez. Am a fan of less to go wrong. 

[garethj]

2 hours ago, grogee said:

FTFY

Good point, well made, but those are mostly aftermarket exhausts which don’t fit well and don’t do a very good job of silencing.

If it fits well (and is fitted well), a standard VW engine is fairly quiet and unobtrusive.

A but like judging all Cortinas by the jacked up rear suspension, wheels that were too wide and a furry steering wheel cover.  Generally the manufacturer did a pretty good job of most things, aftermarket stuff and owners too thick to know the difference isn’t a fair comparison.

[Richard_FM]

1 hour ago, richardmorris said:

Noise and emissions legislation killed air cooled cars.

I suspect my 2cv will outlive me though.

I heard casting the fins on the engine block made the more expensive to cast, & they couldn't match water cooled engines for power per CC.

[Metal Guru]

4 hours ago, garethj said:

Good point, well made, but those are mostly aftermarket exhausts which don’t fit well and don’t do a very good job of silencing.

If it fits well (and is fitted well), a standard VW engine is fairly quiet and unobtrusive.

A but like judging all Cortinas by the jacked up rear suspension, wheels that were too wide and a furry steering wheel cover.  Generally the manufacturer did a pretty good job of most things, aftermarket stuff and owners too thick to know the difference isn’t a fair comparison.

They sound exactly like what they are. Big lawnmower engines.

[barefoot]

Ah yes, the common or garden flat four 1600cc lawnmower. 

[Sham]

I like an air cooled engine, and I don't really see why air/oil cooling can't be used on moderns to create efficient engines - I'm sure there's a reason, but oil cooling should be able to be as efficient as traditional cooling systems.

[MiniMinorMk3]

14 hours ago, bigstraight6 said:

But they just kept on plodding along, in the late 1980’s into the early 1990’s my daily drivers were a succession of cheap VW Beetles, latterly I was commuting daily from Plymouth to Newton Abbot and the old nails did me proud and were simple and easy to keep going.

It's a bit of a myth that VWs ran and ran. Quite a few suffered from burnt or dropped valves on number 3 cylinder. The oil cooler was in the air path of number three so it ran hotter than the rest.

The life expectancy was on average 75,000 miles before a head rebuild was needed.

COAL: 1968 VW 1300 – My First Car; What Were The Odds? | Curbside Classic

 

[martc]

Some motorbikes are still air cooled, mainly mopeds and 125's but there are a few bigger ones eg the  Moto Guzzi V7. There are regs around emissions for motorbikes, the same as cars, but fuel injection and catalytic convertors sort that problem out. The big problem is passing the noise test, the Moto Guzzi barrels are double skinned to keep the noise down, they are one of the very few parts of the small block engine that Lino Tonti would not recognise. Other manufacturers take the lazy way out and use liquid cooling, the water acting as a blanket to keep the noise down.

I may be wrong, but I've a feeling that the noise regs for smaller engines are less restrictive hence most 125's still being air cooled.

[garethj]

1 hour ago, MiniMinorMk3 said:

It's a bit of a myth that VWs ran and ran. Quite a few suffered from burnt or dropped valves on number 3 cylinder. The oil cooler was in the air path of number three so it ran hotter than the rest.

The life expectancy was on average 75,000 miles before a head rebuild was needed.

COAL: 1968 VW 1300 – My First Car; What Were The Odds? | Curbside Classic

 

True, but it’s all relative.  I don’t think the average car engine of the 1950s or early’60s was getting near that, without spending a lot more money.

[barefoot]

My bay went to about one hundred & seventy-five thousand without needing a head rebuild. Everything else was about fucked though.

[garethj]

8 hours ago, Sham said:

I like an air cooled engine, and I don't really see why air/oil cooling can't be used on moderns to create efficient engines - I'm sure there's a reason, but oil cooling should be able to be as efficient as traditional cooling systems.

Oil cooling is very efficient, the thing that helps efficiency is the air to boil ratio.  If ambient air is 30C and a water cooled car boils at 100C, that’s an air to boil ratio of 1:3ish.

On an aircooled car, oil boils (or at least breaks down) at closer to 150C which for 30C ambient is an air to boil ratio of 1:5.

That’s why a water cooled car has a massive radiator and an aircooled car has a relatively small oil cooler.  Air does some of the cooling too (no shit?) but it can be efficient.  Just not very precise.

[artdjones]

Heaters aren't great on air-cooled engines.

 

[bunglebus]

Just now, artdjones said:

Heaters aren't great on air-cooled engines.

 

You say that but if they're in good order they work really well, and almost instantly if they use heat exchangers on the exhaust. Biggest problem I had was engine fumes getting pumped into the cabin

[garethj]

We had aircooled VWs as family cars in the ‘70s and they were serviced at the local VW garage using genuine parts.  The heaters were always reasonable and they could easily cook your ankles if you had it on full blast.

As ever, compare with other cars of the 1950s and early’60s and their heaters.  Oh, that’s right, they didn’t have one, or it was an option and a feeble one.

The problems with VWs heater design were that there was no fan assistance so if revs were low, heat output was low.  Also the heat source from the exhaust is a looong way from the people, especially the windscreen and it’s not insulated so not much of the heat warms you up.

Add to this that most people have only experienced aftermarket heat exchangers which were about half as efficient and it’s not great news.

I’ve no experience of something like a Citroen where the aircooled engine is in the front but I imagine because the heat source is closer to the people, they should be ok.  Add a booster fan plus quality heat exchangers and it should be effective.

A slightly waffle way of saying that half the problem is that the engine is in the back, not the fact it’s aircooled.

[RayMK]

37 minutes ago, bunglebus said:

You say that but if they're in good order they work really well, and almost instantly if they use heat exchangers on the exhaust. Biggest problem I had was engine fumes getting pumped into the cabin. 

Likewise on my 2cv and Dyane.   Fortunately Citroen designed them to be draughty.  The main snag with my two was that in the winter when heating and defrosting would be handy, an air intake restricting cowl/cover had to be clipped to the front so that the engine would warm up more rapidly and idle off choke. This was a standard Citroen item.  It meant that heater flow was pathetic until doing 50mph - but the screen kept frosting up inside and I could not see well enough to do 50.

[New POD]

38 minutes ago, artdjones said:

Heaters aren't great on air-cooled engines.

 

The engine cowling on my Fiat 126 had a flap operated by a wax actuator.  Mine was stuck open. I used to scrape ice off the inside, and wear alot of warm clothing. Warmer than riding a motorbike in the snow, but not much more. 

[Zelandeth]

Noise and accurate temperature control are probably the biggest issues.  Otherwise they would be quite attractive you'd think, especially with the weight savings.

The only heater on an air cooled vehicle I've any extensive experience with is on the Invacar.  Observations there are mainly that the biggest challenge is airflow at low engine speeds.  There's no lack of heat, that's for sure.  The thing is like a bloody furnace once you're up to 40mph or so.  Add a booster fan and I reckon it would perform really quite well, even if the windscreen demister design is still stupid!

Shorter service intervals may also be an issue in the world of today, as the higher running temperatures as I understand it will cause oil to break down more quickly.

[richardmorris]

1 hour ago, artdjones said:

Heaters aren't great on air-cooled engines.

 

Rubbish.

[garethj]

From the late 1960s, VW offered a booster fan for heaters on their aircooled engines.  On Beetles and Type 3s, it was located in the scuttle distribution box and sucked warm air through when the engine fan was turning slowly.  On Type 4s the fan was in the engine bay and pushed the air through.

Both were very helpful and brought heaters almost to 1970s standards, but of course the heat source was still 10 feet from where it needed to be.  Water cooled cars bury the heater matrix right inside the dashboard, with good reason.

[bigstraight6]

20 minutes ago, garethj said:

From the late 1960s, VW offered a booster fan for heaters on their aircooled engines.  On Beetles and Type 3s, it was located in the scuttle distribution box and sucked warm air through when the engine fan was turning slowly.  On Type 4s the fan was in the engine bay and pushed the air through.

Both were very helpful and brought heaters almost to 1970s standards, but of course the heat source was still 10 feet from where it needed to be.  Water cooled cars bury the heater matrix right inside the dashboard, with good reason.

Additional Eberspacher (I’m not entirely convinced that’s the correct spelling) heaters were also available, much like the cab heater as fitted in all todays artic units.

[Rustybullethole]

Have found the heat from my aircooled motos is sufficient to keep my legs fairly warm. Ural did some Siberian cylinder heads which were particularly effective.