en.wikipedia.org/wiki/Napier_Deltic
The same idea powered the Deltic engine, all 18 cylinders and 36 pistons of it!
I also recall Daihatsu claiming 333cc was the ideal size for optimum volumetric efficiency when it released its 1 litre 3 cylinders.
About 15 years ago the motoring press were telling us the 2 -strokes were to make a big comeback led by an (Australian?) company called Orbital. They'd progressed far enough to have a fleet of 3 pot 2 strokes running around in Fiesta Panda cars. Whatever happened to them ?
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Won't meet current emission regs;barely met them when they were tried in Fiestas and others.Very complcated-bore little similarity to a conventional two-stroke.
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I remember many of the car mags testing the Orbital powered Fiesta and proclaiming it to be 'the future'. It didn't half go apparently, and did well over 40 mpg.
A very misunderstood beast, the two stroke. I always think of highly strung motorcycle engines that make a million hp per litre, seize on command, and need rebuilding every 10,000 miles. Yet talking to a microlight pilot friend, he tells me they have a few planes on the club fleet with Rotax two strokes and they're brilliantly dependable. They get stripped down and rebuilt every 300 hrs as recommended by the manufacturers, but rarely need anything doing to them until well over 700 hrs. They have 1000 hour + engines still running well.
Bear in mind as well, these things are sympathetically warmed up, but otherwise have a very hard life, spending about 90% of their running time between 5500 and 7000 RPM. Failures in service are extremely rare.
Cheers
DP
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I'll concur with the Suzuki Swift 993 3 pot. We had one here & it'd do 46MPG harassing 3 series in the outside lane & near 60MPG driven like miss daisy. Who needs a diesel!
They have an uneven beat but you get used to it.
Also reliable enough to be used in Microlights, especially the USA where it's called the Geo.
The reason they are slow to start is they run fairly archaic style management that is slow to sense the crank positions. It's also multi point injection unlike a lot of small cars. Good for 50BHP in the Suzy.
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40 years ago I had a Wartburg with a three-cylinder 991cc two-stroke engine. It was extremely smooth and lively when revving, presumably because of the two-stroke firing cycle, but at tick-over it was anything but.
Wasn't the Rootes Group TS3 diesel (originally designed by Tilling Stevens) a bit different because it had three horizontally-opposed cylinders with six pistons?
Last year I saw what may have been the most famous installation of that engine, in the former Ecurie Ecosse racing car transporter, at the Circuit des Remparts at Angouleme.
I asked the driver/mechanic to start it up for me, which he kindly did. Even though it didn't have the renowned transverse silencer at the front it sounded lovely.
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Wifes 1.2 Polo 3 cylinder is a lovely little engine. Revvy and energetic and will run at 80mph all day which isn't bad for 55bhp!
Downsides, economy not as good as you would expect even when driven gently and a slightly uneven tickover.
Would still have another though. Its an engine with a little bit of character!
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Revvy and energetic and will run at 80mph all day which isn't bad for 55bhp!
That's the problem with most of them. Revvy they may be; but knackered by 60K.
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Wifes 1.2 Polo 3 cylinder is a lovely little engine. Revvy and energetic and will run at 80mph all day which isn't bad for 55bhp!
We have the same engine (although I believe a more powerful version) in a Seat Ibiza - it does run very well when revved, but at slow speed around town etc, it's juddery to the extent that it feels like there's an engine mount missing (I'm assured there isn't!).
Downsides economy not as good as you would expect even when driven gently and a slightly uneven tickover.
Economy is a known issue with these engines - pretty well everyone seems to get way worse consumption than VAG suggest.
We also have 3 cyl Colt - it's a little lumpy at tickover but once on the move (even at low speeds) you'd really never know it was only 3cyls. And it's economical too.
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Suzuki's 2-stroke triple bike engines are lovely to ride, hugely characterful and with 3 bangs per revolution, go very well indeed.
I have a GT380 which is uncannily smooth, perfect primary balance but you do get a secondary harmonic shake at tickover.
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The Rootes Group had a 3-cylinder 2-stroke diesel engine.
The Ecurie Ecosse transporter is probably the best known vehicle using it
(my entry for geek of the week)
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Did it have six opposed pistons working through rockers on a central crankshaft? Anyway the Commer turbodiesel was a very sporting sounding lorry engine, and they used to go briskly too.
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Yes sporty indeed Lud........ a bit like this eh?
tinyurl.com/3mas76
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Wonderful! Brought tears to my eyes.
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Some fascinating answers here thanks. Just been down to my friendly Skoda Dealer (who supplied my car) and tried 1.2 HTp petrol triple (12 v) and 80 BHP 1.4 TDI triple. Intriguing little motors and found them great in different ways. The 1.2 petrol pulls well low down but really likes to spin and sounds cracking as you wind it up. Does have a slightly "fluttery" idle though and a bit hesitant coming off idle as though it wants to stall, but it never does. Diesel pulls well but with that same slight hiccough from idle but still likes to rev and has the same off beat growl. Both felt mechanically smooth and I am told they both have a balancer shaft. 1.4 tdi certainly sweeter once spinning than 4 pot 1.9 IMHO.
Edited by Mattbod on 20/06/2008 at 17:43
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Another comment about V8 engines on this thread about 3-cylinder ones!!!!!
V8's might be very well balanced dynamically but the interference pattern of the pressure waves in the exhaust system undo all that as far as perceived smoothness goes! Unless it's heavily silenced, that is.
Edited by Sofa Spud on 20/06/2008 at 18:27
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The very varied opinions on these modern four-stroke 3-cylinder engines make them seem even more interesting.
Screwloose, are they all knackered at 60,000 as you say the VAG unit is (despite its hearty output or perhaps because of it) or are some as durable as other modern engines?
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Lud
That wasn't specifically about the VAG engine - they'll often have thrown a chain and died long before then. [Their perkier 4-cyls aren't much better.]
Most of the 3-cyls don't seem to make old bones; the Corsa one will usually struggle to meet MOT emissions testing at anywhere from 40K upwards due to the amount of worn piston blow-by upsetting the readings. [I just re-submit them with the smoke-pluming breather pipe disconnected and replace it after the test.]
None of these lawnmower engines should be entertained as a safe second-hand buy. High specific output = high wear.
Edited by Screwloose on 20/06/2008 at 19:46
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>>None of these lawnmower engines should be entertained as a safe second-hand buy. High specific output = high wear.
55bhp from a 1.0 litre engine isn't much though!!
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Screwloose I'm afraid your argument confuses me. Surely ANY small engine will fail prematurely if thrashed mercielessly and if not maintained properly. I havread elsewhere that a 3 pot is sturdier because of its short and rigid crank. I find your Vauxhall argument hard to believe as I see lots of early millenium 12v Corsas (the 1 litre triple) on the road as popular with learners. I don't think 60-70 bhp for a 1.2 in the case of the VAG as particularly high by todays standards and that engines limiter is a relatively tame 6500 rpm. I don't agree that the VAG 1.4 four pot is perkier, in fact i found that engine thrashy and gutless. High specific output needn't mean high wear. How do you explain 100 bhp per litre Honda VTECS going twice around the clock?
Edited by Mattbod on 20/06/2008 at 20:54
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Whatever the reason - and outputs do indeed vary between makes; these 3-cyls seem to wear very fast. The fact that cost and weight are significant factors in their development may well be involved. [A Honda VTEC may produce it's max rated output very rarely when compared to a 1.0ltr unit.]
My reference to "perkier" 4-pot versions was aimed at the high-output [100PS] VAG units; many of which are shot by the end of the warranty. [If not run on 98 octane fuel.]
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My girlfriend and I both bought 5 door cars recently after the arrival of our daughter. I got a 15 year old civic VTi with 70k for £1200, she got a 9 year old 12v ibiza with 60k for £2700. As you say about power usage, i very rarely stray into VTEC territory, but driving her car i find my foot pressed hard to the floor about 90% of the time. I think the 94bhp/litre, 8000rpm civic will be going long after her 54bhp/litre, 5750rpm ibiza has gone to the crusher. So far I've replaced worn ARB bushes and warped discs (which were like that when i bought the car), she's had 3 new coilpacks after it started misfiring and now it's started stalling randomly... and i'm just counting the days until the cam chain slips. Cheap, simple, reliable are three words that should never be used to describe these engines. And whoever said 3 pots are revvy and eager has obviously spent their whole life driving absolute dogs.
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And whoever said 3 pots are revvy and eager has obviously spent their whole life driving absolute dogs.
They usually are revvy and eager - I know the one in my old Corsa was
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Bit like the Ford V4 which looked like a good idea at the time.
I suppose the Lancia one, which was a jewel, cost more to make.
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will usually struggle to meet MOT emissions testing at anywhere from 40K upwards due to the amount of worn piston blow-by
Screwloose, are you very sure it's to do with wear? I would be quite surprised - a piston in an individual bore in a 3-cylinder engine is just like a piston in an individual bore in differently-configured engine, isn't it? From quite some time ago, I recall issues with flex in the blocks of light-alloy engines causing this problem. Is the Corsa engine light-alloy?
None of these lawnmower engines should be entertained as a safe second-hand buy. High specific output = high wear.
Surely this goes for *any* performance engine (which I define here as one giving more than around 100 hp (DIN)), and means therefore that no "sporty" cars are safe 2-hand bargains!
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Lud
Most of the 3-cyls don't seem to make old bones;
Re daughter's Suzuki Swift previously referred to...it has clocked 110k+ miles; is constantly driven in a 'lively' manner and has never had any engine repairs or attention no doubt due to regular servicing.
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Another comment about V8 engines on this thread about 3-cylinder ones!!!!!
Sorry, Mr Spud :~D
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biggest issue with 3 cylinder engines is what happens when you loose a single HT lead
I had a hire car with a 3 cylinder engine and one of the HT leads died, so you end up with a 2 cyclinder engine which is totally none viable, not even able to crawl home
Compared with most 4 cylinder engines which will happily continue to drive if they loose a single HT lead, running then on 3 cylinders
Practical consideration this one
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one of the HT leads died so you end up with a 2 cyclinder engine which is totally none viable not even able to crawl home
...and that's a real issue with a VAG car and their generically unreliable coil packs - we've had 2 failures on our Ibiza.
What was a real pain is the "Seat Assist" (which is the AA) can't do a warranty replacement so they'll put a generic spare in and then follow the car to a Seat dealer to have it replaced. AA man said it could be driven on 2cyls with the injector disconnected - I refused to allow that.
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OK. You've lost me here with second and third generation harmonics.
I was taught that a horizontally opposed was 'in balance', and could just about understand the angular acceleration of the con-rod and piston concept, but could never understand why 2CVs and beetles vibrated so much.
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OK. You've lost me here with second and third generation harmonics.
It's not as bad as it sounds, it's just comparing the frequency of vibration with the frequency of the crankshaft.
If a cycle of vibration coincides with one full turn of the crank, that's a primary vibration. If there are two cycles of vibration per rev, then it's secondary, and so on. Sometimes, instead of primary, secondary, etc., these may also be called called first order, second order, ...
So, for example, if you are designing a vibration isolation system for the torque from a six cylinder 4 stroke engine; there are 3 firing events per rev, these dominate the fluctuations in torque, and so, the third order vibrations are the dominant ones in the spectrum, and so if the engine runs at 3000 rpm, i.e. 50Hz, the dominant torsional vibration will be at 150Hz.
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And I am under...................................
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I always find these things fascinating, even if some (much) of it does go over my head. That said I understood the last post (I think)! :-)
Cheers
DP
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There are a lot of negative comments from the "experts", the only positive ones seem to come from owners/users.
My 4 yr old VAG 1.2 3 pot has just flown through its MOT with flying colours.
Just under 53,000 miles (oil last changed 43,600)
Fast Idle CO 0.004% vol
HC 0 ppm
Lambda 1.004
Natural Idle CO 0.020% vol
I have changed the oil approx every 11-13,000 miles - which is a little beyond the manufacturers recomendation. Its never drunk a drop of oil between oil changes.
I guess from the above data, its on its last legs and about to collapse in a heap at 65,000 miles...... ;)
Edited by brum on 21/06/2008 at 01:24
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Ah. Dr. Frederick William Lanchester, FRS:
www.jstor.org/stable/768769?seq=6
No diagramme of his twin-cylinder engine, unfortunately. I've got one in a book somewhere, a picture tells a thousand words.
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Just thinng of Screwloose mentioning frantic small high specific output engines being worn smooth at 60k. Wonder how the new Fiat Turbo twin will fare with its 105 BHP. Wonder how they will smooth it out and whether it will be a 360 degree crank ie pistond firing at same time or 270.
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