Quote:
Originally Posted by dentprone
I have nixed the two-cylinder idea...probably stopped me from doing something stupid.
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Ohhhhhhh.... too bad. And it's not a stupid idea. If you had the time and energy to experiment with it, I think it would be a fun project! On the other hand, if you are just trying to get back on the road, a burned rod journal is almost always repairable, even if the crank is cracked. Either way you just and have it mag'd and reground. If needed you salvage a replacement used rod or have the burned one rebuilt. Or you buy a used crank and one rod if the crank is cracked and/or the rod is beyond rebuilding (any automotive crank grinding shop can help you with a visual inspection, precision measurement, and magnaflux test, everyday stuff for them).
Your 2 cylinder idea has a few things going for it, and plenty of precidence.
It may very well shake from the out of balance condition, but then again, my 3 cylinder metro already seems out of balance and it runs perfect
Seriously though, a 2 cylinder may not be as bad as some would think, you would have to try it. I don't know if you would have to change anything on the intake side, the metro is common throttle body efi, the ECU might take away enough fuel so it could run properly with only 2/3 the displacement. If not, you might be able to reduce the fuel pressure slightly to bring 2 cylinders on a 3 cylinder system in to stoichiometric range.
Precidence: A completely different application than ecomodding I know, but an example none the less; There have been many, many salt flats racers who have pulled one rod/piston assembley to be able to race in a smaller engine displacement class... at the track no less! This old timer I was talking with said you just drop the oil pan and remove the rod cap, wrap the rod journal with leather and a hose clamp (to plug the oiling hole). Pull the head and remove the piston and rod out the top, then disable the valve train for the dead cylinder such that it's valves never open.
If I were expecting to convert a 3 cylinder Suzuki for a commuting experiment, I'd machine a non-rotating bob weight that clamps to the rod journal, similar to what Engine Balancer's use. I make it the same weight as a Metro piston and rod assy, and non-rotating so it would seal up the oil hole with no gasket or seal, just metal on metal. I'd grind the two lobes off the cam, which sounds to me like the easiest way to disable an OHC engine's vales train for one cylinder.
With that 'dead hole' not pumping dead air (no piston remember), I would imagine it being much more smooth operator than say, pulling a plug plug wire on your 1 liter metro engine. If I'm not mistaken, the journal rotation is such that you could select cylinders that allow it to fire every 360 degrees of crank rotation. Even if I'm wrong, you aren't making enough power where you need to worry about cracking the crank from the unbalanced torsional load. Again, you'd have to try it. my 2 cents