Corsa petrol - no go in higher gears

Is the Corsa 3 cylinder a 2 stroke engine?

If its a cylinder fires every 120 degrees, how can it be four stroke, unless the firing sequence is every other revolution?
 
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Hell no - it means that there is one cylinder providing the power stroke at every revolution. Nothing new there but the design of the triple means that crankshaft vibration is minimal.....also the crankshaft length is reduced which helps too.
Remember the old British twin cylinder bikes which had both pistons rising and falling together? It didn't take the Japs long to realise that a 180deg crankshaft smoothed things out tremendously, preventing the engine from shaking itself apart.
John :)
 
For sure, but an unknown quantity to me......I did hover around when one of these engines was being refurbished with new rotor seals and so on but the owner never got it to run well. I've never seen so many sensors on an engine, but I was suspicious when I noticed the main rotor shaft had significant scoring :eek:
I don't know if a refurb on these would ever be cost effective but I reckon if Mazda have given up on it then we have no chance!
I couldn't see how the rotor seals could ever last without oil added to the fuel which must do away with any anti pollution arguments these days.
John :)
 
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On the Mazda rotary oil is (was?) added to the fuel. Don't think it has a conventional sump.
I'm not convinced about 3 cyl engines being smooth, friend had one back in the 80's, a Daihatsu (?) so it's nothing new
If short cranks, balance weights and counterbalance shafts were the secret to smoothness , the old Ford V4 in my Corsair should have been a gem!
 
Triples need to be over square in design ideally, and balance shafts are the answer to most engine vibes.
I remember the V4 well enough.....prone to popping head gaskets in the vee, and thin big end shells to fit on the crank pin .....not the best for longevity!
John :)
 
I noticed with the Cora 3cyl that it was quite shaky on its mounts at idle.

Back to full power on take off though and that's the main thing.
 
I guess at the end of the day, the reason for 3 pot motors comes down to economics over it's 4 pot brother.....lighter, less friction, smaller, theoretically better fuel consumption, fewer parts etc etc.
I'm not a fan personally, and I'm still a diesel chooser and user.
John :)
 
It doesn't seem natural to me, OK you can turn off the spark and the injection so you don't wash the bores with unburnt fuel but isn't it going to be as smooth as an engine with a few cylinders down?
 
Probably one of those ideas that will have a short life - who knows? I have no experience of these but on a camshaft I have seen, one cylinder was disconnected from the others courtesy of a hydraulically operated spline. On demand, the cam was coupled together quickly and four cylinder power was restored.
Apparently this can also be used on a 3 cylinder motor which means that the engine becomes a twin on occasion.
The jury is out!
John :)
 
Let's hope DIY Spanner's family never get cars with engines like that.
 
How about a V8 for 1.0 to 2.0 capacity engines, the engine firing at every 90 degrees.

Smoother and economical because the same quantity of fuel/air in a 4 cyl engine would be spread across eight firings instead and optimize power?
 
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