We hear a lot about cam belts busting. I had the secondary chain break on an XK motor, so that's not the bomb proof answer. There have been cunning devices with eccentrics and connecting rods, and suchlike, fine and silent but expensive.
But what about gears (some of us would LIKE the music)?
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Belts snap.
Chains are noisey.
I agree. For want of a better word 'cog' driven v4's work a treat on bikes.
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I'm sure I've seen gear driven replacement sets advertised for the Land Rover TDi engines.
Of course one answer would be to mount the cam shaft lower in the engine and use some sort of connecting rod (lets call them a push rod) to operate the valves. ;-)
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Didn't the old V6 Ford engine have gears but to make them run smoothly one had some sort of composite material for the teeth. Then that would strip off the gear and you were looking for the AA.
David
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Nah, you don't wanna do that, you want to change the shape of the cyl head, turn the valves through 180 deg and then the camshaft can work them directly.
;-)
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That wonderful old motor the Rover V8 (Buick derivation)is just such a design, need to budget for replacemnent rods and followers every so often but there are no belts to break..............and a great soundtrack into the bargain!
Can someone tell me if you regular Back Room Boys have jobs to go to, or are you just hoping the boss thinks you're hard at work? (I'm only teasing). I've really enjoyed scrolling the various threads through so far, congrats to HJ for setting it up.
Rob
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work?
I prefer the phrase "Gainful employment"...
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Rob,
I am my boss and I keep telling myself to get on.
David
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I've just given myself a verbal warning for non-work-related use of the Internet.
That must be a couple of dozen so far ...
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a verbal warning isn't worth the paper it's written on....
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Andrew
Even better than that, you could mount the valves in the block, rather than the head, and drive them direct off the camshaft. You could call them 'side-valves'.
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Sorry Richard, didn't read all the posts ...
Great minds etc.
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Or you could have the whole cylinder liner, with ports, driven by an eccentric on the crankshaft, and call it something like a "sleave valve".
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Why not do away with the pesky crankshaft and valves altogether and suck the mixture into the crankcase, squirt it through a port to the cyl head on the downstroke while emptying the exhaust from the previous stroke though another port?
While we're about chucking stuff away, why not bin the electrical stuff and spark plugs and put diesel in it for a *really* simple motor?
Model aircraft engines, anyone?
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> Why not do away with the pesky crankshaft ...
Getting simpler!
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Let's all ride horses, and do away with that infernal combustion thingie!
A. Luddite
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Ooops!
Brain fade in Spennymoor today.
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I have the luxury of my own office. I can shut the door, and people think I'm working harder than usual.
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me too.
Deltics don't have cambelts...
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Starting to get reports of chains failing on Nissan Almeras. The 1.4s and 1.6s have two chains and many of these cars are driven by the tartan carpet brigade who stick rigidly to 10,000 mile services even though that means every four years.
HJ
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I had the timing chain go on my Ariel Red Hunter KH 500cc twin when I wos 16 years old with no cash to get it fixed.
Davies of Chester wanted £30 to fit a new chain so it remained in boxes. Very sad. Chains do break.
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I seriously wonder if a two-stroke diesel would not be more economical than a four-strokel, setting higher fuel consumption against the cost and worry of cambelt failure/replacement.
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A few years ago Toyota, among others, were playing around with two stroke diesels. As I remember it, they had a straight six for use in luxury cars. It would probably have been a very lovely engine, but presumably emission problems killed it, as with the Orbital 2 stroke which Ford were going to put in the Fiesta.
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