I was visiting Bell equipment yesterday. These guys make 50ton articulated dump trucks amongst others, that are badged as either Hitachi, Bell or Deere. Apparently one went up a close to 1:1 grade with a full load that a landcruiser couldn't get up. (I know I am sure that a landy would have made it.)
I went around their test track and let me tell you LR have got a thing or two to learn about the so called "command driving position." Getting back into my disco felt like dirving a punto after that beast.
Anyway, I am not sure how I can justify it or what I would use it for, but I want one.
On or around Fri, 24 Jun 2005 13:03:58 +0100, Steve Taylor enlightened us thusly:
'ere, now speaking of 101s - a scheme came to me in a flash of insanity or inspiration this morning.
Bolt 2 TDi engines together, you get a 5-litre straight-8 TDi. Considering the amount of space in front of the rad in the 101, d'you reckon it'd fit?
OK, 's not quite that simple - you'd need some form of mod to the rear crankshaft in order to drive though the front end of it, and it has to be possible that the back end of the rear crank would not be strong enough, although I rather doubt that.
If only I hadn't packed in smoking 18 months ago, I could have had a smoke of whatever he fills his baccy tin with, as well as that pint!! :-)) Reckon it would work better as 2 V8's bolted together to make a V16, though! And I bet you it would sound a lot nicer than a couple of diesels, eh? Oh, and the load bay could be filled with 120ltr lpg tanks to feed it. Practical...? No! Fun...? Yep! Badger.
Seen this done in tractor pulling circles, with Jag V12's and I6's, no reason why it couldn't be done with any other engine, I shouldn't imagine, unless there is an inherent known crank weakness?? The more cylinders each engine has, the smoother its own power delivery with less torque pulsing, therefore the easier the stress can be coped with by the rear crank. Hmmmm... V24, 10.6ltr.... hmmmmmmmmmmmmmmmmmmmm............................... Badger.
personally, i reckon you'd be better off going down the route that the old mini-mokes did. have a seperate motor powering each pair of wheels. only problem with that is requiring two transmissions, and you'd probably want them to be automatics. but worth a think.
On or around Fri, 24 Jun 2005 19:35:29 +0100, steve Taylor enlightened us thusly:
the front end of the crank would need a spline or something. I was originally thinking of a rigid bolting job, which lets you select the firing order (by varying the angle between the 2 cranks) - I tended to think that arranging crank1 at 90° to crank2 such that engine2's firing order interleaves with engine 1 would work - starting with 2 engines that fire
1-3-4-2 you'd and renumbering the aft one to 5,6,7,8 could produce for example and 8-cylinder order which went 1-5-3-7-4-8-2-6, or indeed various others - you could have 1-7-3-8-4-6-2-5 by having it 90° out the other way, say. I doubt it makes much odds.
I spose I should say that the original idea was 2 reliant 850cc engines put together to make a 1700cc 8...
on the roof? Mind, it'd not need as much cooling as Badger's V16 - the TDi runs cooler anyway.
On a 101 ambi, you could put radiators above the windscreen, ducted out through the roof...
The major problem would be to get the two engines running the characteristic, i.e. not fighting each other. I guess (from railway locomitives) that you'd be lucky to get 150% more power than a single engine. Somewhere on the web is a discourse by someone who put 2 (proper) Mini engines together, complete with the maths on why the power output isn't simply x2
Thats a great idea. Any idea where one can buy radiator core stock material to roll ones own ? All you buy from Allisport etc. is the service of someone who can TIG pretty header tanks. The radiator finstock must be available from someone....A 10 minute Google yesterday couldn't find the source though.
What happens if you have long intercooler pipes ? Wouldn't that give you an 'orrible turbo lag, since you have to pressurise the pipes of the intercooler.
On or around Sat, 25 Jun 2005 08:25:11 +0000 (UTC), beamendsltd enlightened us thusly:
I dunno how as they'd fight, as such, if bolted rigidly together. They're both turning the same way, after all, and every power stroke adds to the torque. I daresay you don't actually get 2x the power of one, but equally I don't really see where you lose that much either. I don't, in fact, know what angles your typical straight-8 crankshaft uses, but it ought to be 90 degrees, in order to get even firing sequences.
On or around Sat, 25 Jun 2005 23:27:19 +0100, steve Taylor enlightened us thusly:
I'd think that a slight phasing problem would be more likely to make it run slightly less evenly. Even that's not necessarily a problem: some shortish time ago, the cunning Japanese decided that making multi-cylinder GP bike engines fire all their cylinders close together was better than firing them evenly: the Big Bang engine, it became known as. Granted, it didn't make more power (but didn't, I don't think, make much less), but it did have an effect on grip - the pulses in the power delivery had an effect similar to ABS and gave reduced wheelspin, the latter being the limiting factor at the time in deploying more power.
Going back to basics... every 4-stroke cylinder in an IC engine absorbs power to a degree - all the time due to friction and more once per cycle due to compression. The combustion process, allied to a heavy flywheel on a single, gives more energy than is absorbed and the motor can do useful work. Adding more cylinders means you can reduce the flywheel mass - I suspect an
8 (or more)-cylinder doesn't technically need a flywheel at all as whichever cylinder is currently compressing is matched by another on its power stroke, for an even-firing engine (i.e. one with evenly spaced crank pins). It might be that the flywheel does other things, like smoothing the power delivery, and in the case of automotive applications, the flywheel is an ideal large flat surface to run your clutch on; if you didn't have such a flywheel, you'd need some other form of clutch.
What I don't see is how adding another set of 4 cylinders, not perfectly synchronised, is going to lose a lot of power. I can see how having 2 complete systems could go out of sync, such as for example having 2 generator sets driving an electric transmission - one could be doing much more work than the other; in the same fashion, 2 complete transmissions (a la 4cv citroen sahara[1]) could be imbalanced - mind, in some conditions, being able to mix the power levels non-linearly would be an advantage, especially off-road.
I don't see the problem of balancing power from 2 linked engines as being that much worse than balancing power from 2 or more carbs. Probably, you'd set it up on a dyno, and tweak the pump linkages to get maximum output.
[1] twin engine 4x4 version of the 2cv. For them as didn't know
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