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Engine balancing
In college we had a VW beetle that was converted into a 2cyl. Got over 60 mpg at 55 mph back in the late 70's.
I've got several Sundances laying around here and want to make a 2 cyl 2.2L removing 2 pistons and rods is simple enough and removing the rocker arms is also easily done, but what about crank balancing? I've already tested to see if the 2.2 in one of my sundances to see if it had the power to go up the biggest hill I could find from a stop and accelerate on 2 cyl. and it does. Any machineist have any ideas? sure would be nice to get 60 mpg with the cost of gas |
#2
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Probably have to find a way to permanently attach the appropriate bobweights to the empty crank pins - as the balancing shop does when they spin your crank up. Since you'll have it completely apart the balancer guy should be able to work it out.
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#3
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#4
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The most efficient engine would be the one that could run at WOT all the time. It reduces pumping losses.
It only takes 15 hp to maintain a speed of 55mph (with little wind speed) in a 1994 Ford Taurus. A sundance weighs 1000 lbs less and makes about 100 hp. So 50 hp is more than enough to move it down the road. No I'm not building a speed demon, I just want something that will get me from point a to b and get better mileage than I get now. It'll get better mileage, but it will take longer to get up to speed. I live up in the sticks and drive all hwy to work. Never any stop and go. So once I hit crusing speed I just have to maintain that for 30 miles. Actually I've driven my sundance now with 2 plug wires off and it accelerates about the same as and Automatic Omni. The 5 spd really makes a difference. Yes a 1000cc motorcycle only gets at best 40mpg. But a bike with similar weight and 500cc gets 60mpg. If you could maintain a certain speed with a 1cid engine it would get better mileage than a 135 cid engine. Less air means less fuel over the same distance. I was thinking that since the crank has the pins 180 degrees off I could take one piston up and one down out could I have the weights cut off or maybe just take the pistons and rods out and be ok. I was just wondering if someone knew. |
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I question the accuracy of this statement. I suppose it's theoretically true, but I think in real life that the most efficient engine runs at it's most effecient speed/power band, all the time which may or may not be WOT. This is where hibreds have come from. The hydro carbon engine doesn't need to worry about variences in power demands. The electrical motor does that. If we are working entirely on theory, the single biggest factor in mileage is vehicle weight. Everything else(including engine power output) is secondary. In any case, sorry for drifting off the topic.... for the balance issue, you could probably figure out from a balance guy how much weight to compensate for the rod and piston. When they balance a rotating assembly they bolt on a weight to compensate for the piston and rod.(must be some relation to the actual weight of the piston and rod. you could weigh them once you have them out) I would think You may have to make some mods to the journal to make it stay in place, and have suffecient clearance. |
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But anyway, keep us posted and let us know how it went. I admire your ingenuity. |
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Back in the late 70's Chrysler came out with the Omni Mizer. My service manager had one and said he got over 50 mpg with that. And they had the Mizer pickup lines that according to the books got 26 mpg out of a full sized pickup. Neither had much power but were able to get good mileage from point a to b. Why aren't these still produced? Because most of the comsumers don't care enough about mileage to give up their power and luxury. Of course tightening emission standards have also choked those numbers down. Personally I'm a cheap skate and don't want to spend anymore than I have too.
I think that an engine designed to run at WOT all the time could have a very long life, but the key is designed. Most engines are not constant rpm engines. And of course I'm going to need more than the minimun hp to maintain speed (I've got to go uo some pretty steep hills) I've got more faith in chrysler designs than japanese (especially 70's). I'm hooked on the durability of the 2.2L. I had a Horizon (I should have kept) I'd run WOT 6300 rpm until the oil light flickered then I'd have to shut her down because all of the oil was run out of the crankcase and was ontop of the cyl head. At that rpm it just can't drain back fast enough. I drove it for 40,000 miles always beating on it and never had a problem. Lets assume that the 2.2L has exactly 100% volumetric efficiency. I have run about 2500 rpm to maintain speed up the larges hills here. Thats 84375ci of air per minute at 50% throttle. Even if I have to go WOT up hills (which I didn't have to do) thats moving the same amount of air per minute but since during cruizing I'll be using approximately the same throttle as I am now. Less air per minute = less fuel per minute = better mileage over all. I hope I can get the balance figured out. I'll let you know the results. |
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i would think if you had 2 journals that are 180 degs. apart,,that would be the 2 too use,the other 2 could be run without rods and pistons..all though you would have too plug the oil holes in the crank journals that aren't used or remove all of the rod except the big end and bearing,get the 2 big ends too the same weight and bolt on just like a piston rod combo,,should work
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#9
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I think that the easiest thing would be to remove the spark plugs from the 2 'dead' cylinders. Then remove the valve train for those cylinders as well. Alternatively, you could remove the exhaust valves instead of the spark plugs.
At that point, the only loss comes from the rings. And the crank is still properly balanced. It would also be rather easy, to revert back, if you wanted to. |
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