I would like it if people stopped spreading this misinformed crap.
They don't generate enough energy to overpower the full-speed pulses on their own.
That's the only reason they don't explode.
Attach another engine to that one and it sure as hell CAN explode.
Bit hostile aren't you? A redstone engine running on its own will not explode. It runs faster and faster as it heats up. For the purpose to which I was replying, attaching a single redstone engine to a wooden pipe, they are entirely safe. I have left them running for months in-game with no issues. I was commenting on the picture the other person posted, not some theoretical daisy chain of engines.
It is nice to know that if you do something like chaining a bunch of redstone engines to each other they will explode, I've never tried that because it seems stupid.
I've also never had a steam engine on its own explode, even when I loaded it with a full stack of coal and left it for days.
I'm a bit hostile to it
now, yes, because the number of times I've had to SAY that is well over a hundred now.
It helps that I'm a "hostile" person :V
The explosion is, as I said, the penultimate of the engines
storing energy.
Give it nonstop work, sure, it won't explode unless you're pumping energy INTO it from something else.
If the machine it's attached to stops having things to do, or you haven't attached it to a machine, you can bet your ass it'll explode if you leave it going. (E: Should specify -- redstone engines don't on their own, they naturally dissipate more energy through the piston movement than they generate in the same amount of time)
The new ability to pump water into engines that came with 2.2.x is a dissipation mechanism as far as I know; if you use it when it's not appropriate (the engine isn't being able to store anything), it'll probably sap the engine's productivity. That said, I don't have the updated documentation on that, so I could well be wrong.
The whole point is that the statement I was rejecting was made far too broad. Redstone engines CAN and DO explode.