2 cyl civic test?
 

Hi I'm new to the website and have been trying to play catch up on all the mpg tips. I have a luxury that many do not in that I will be changing the motor in my daughters 1.5 93 civic while the old one still runs well. It has 150,000 miles on it but has just recently blew an oil ring. I found a used low mileage motor that will be cheaper to put in than going through the old one. But before I pull it out I thought I'd play a little. I plan on seeing the difference in mpg by disconnecting cylinders. I do not have a scangage but the plan is simple. Fill up run 80 miles or so straight highway. Refill and check mpg. Take it in my shop, remove the rocker arms on the bad cylinder placing a hose clamps with rubber over the oil holes to maintain oil pressure and disconnect the fuel injector. The reason for removing the rocker arms is to keep from confusing the oxygen sensor. Retest mpg. Do the same test again, this time pulling out the spark plug to see the difference between the "air spring" affect and no air spring. Once these tests are complete and I can see which is better - air spring or not, then I will proceed with unhooking another cylinder, the one that is 180 degrees from the one already disconnected making it a two cylinder motor. I know the power loses will be great and the vibrations incredible but why not? What do you all think? Am I missing anything?

Many ppl here have tried unplugging the injectors with little or no gains but only a few have disabled valves.

Go for it, but try just disabling 1 cylinder first. Speaking from my own experience, acceleration really suffers on a 1.6 liter Honda engine when you disable 1 cylinder.

Put your car in the "garage" and start a gas log and show your valve disabling results for all to see.

So this has been tried before? I know others have tried disconnecting the injectors but disabling the valves and pulling the plug has been done? I don't want to reinvent the wheel or waste my time if no gains are expected. Can you provide me with a link to the tests?

If I'm understanding correctly, you disconnected the injector, rocker arms on both intake and exhaust valves? Did you pull the spark plug or leave it in? I know hp would be greatly affected but what happened with the mpg? What car was it on?

Disabling the valves and pulling the plug will be what makes this worthwhile.

Please take a look at this thread:
https://www.gassavers.org/showthread.php?t=7400&page=2
There's an intense discussion going on in there about very similar stuff, and real experimental data from you could answer and close it once and for all.

I can only forsee getting worse mileage. Even if you were to disable the valve acuation of those 2 cylinders (I would attempt #2 and #3), you will still have pumping / friction losses from those cylinders (even with the spark plugs out).

I just don't see where you are going to benifit, perhaps reducing pumping losses past the throttle plate? (As it should require to be opened more)

Hmm...I wonder what would happen if you entirely removed those pistons and connecting rods. Would the resulting extreme imbalance cause stuff to fly apart?

I don't understand your last question. If you are asking why disconnect the valves the reason is simple in my way of thinking. If you don't disconnect the valves air will be pumped into the exaust instead of carbon monoxide. This air mixing in with the cylinders that are still running would make the exhaust appear to run lean. If that were the case I think the computer would compensate by richening the mixture defeating the desired goal.

I thought about that too. If there was a way to remove the piston without pulling the head I would love to try it. One would have to cut the connecting rod short to the crank and leave it installed to maintain oil pressure. Yes, it might be out of balance but I would not be too concerned as the motor will be discarded in the end. I really don't think the frictional loses will be that great though. If you have ever pulled a high mileage motor apart, the pistons really slide easily. Seeing as there will be no heat generated by combustion in these cylinders I would think the loses would not be that bad. Is there any other threads in the archives that I could read where someone has done what I am attempting?

If I'm unhooking two cylinders in the end why #2 and #3? These cylinders are not 180 degrees apart are they? I would think to even have a shot at success it would have to be 1 and 3 or 2 and 4 or vibrations would be much worse.