Removing pistons to save gas

I know this is an odd question. I have a 92 s10 v6 that has a bad valve. I bought it this way because I wanted the body panels for my 84 s10 that is a rust bucket but only has 64,000 miles on it. I was thinking of the old caddy 8-6-4 engines that was produced and flopped. I drive maybe 40 miles a week and its all intown driving. The speed limit is never over 40mph. It all stop and go traffic, I would say 8 lights per mile and they way there set up, you might make it thru 2 lights at a time if your lucky. I was thinking of pulling the pistons out of 4 or 3 cylinders, and stopping the valves from opening. There is 2 injectors in the throttle body, thought about pulling one of them out. I know the computer is going to freak, and throwing codes and revert into a default loop. If worse comes to worse I can always revert to a v6 that has a carb and a distributor. Does any of this even sound plausable?

One other problem I foresee is if you remove pistons you’ll need to remove piston rods too. The rod bearings have oil feed holes and those will need to be covered. There’s also the issue of engine balance.

You might do better by getting a scooter for short trips.

Why do people even consider these types of things? Life is dffficult enough.

About specifics in your plan. If you take out 3 and 4 pistons, and disable the valves to those cylinders, you will still need to have both injectors working as each supplies half of the cylinders. Also you are going to have gas pileing up in the intake runner3 to 3 and 4. Also you will not be saving any gas unless you reprogram the computer to recognize that you only need fuel for 2 cylinders out of each injector.

I guess you could do it but why not just transplant a 4 cylinder and all electronics instead.


I just thought of a better way to disable pistons. That is to disable 1-4-5 or 2-3-6 pistons, their related valve rockers, and the injector that supplies the intake runners supplying those cylinders. You could let the spark plugs keep on firing as there would be nothing to burn. You cannot get away with removing the pistons and rods without really unbalancing the engine. Even then you are going to have a very rough engine at idle and under power. I don’t know if the ECM will adapt to the new conditions or throw multiple DTCs.

Just some ideas. Let us know if you proceed in this experiment.

If all you drive is 40 miles per week and your truck gets 10 MPG (for example), that means you are only using 4 gallons of fuel per week. At $4 a gallon that is only $16. If gas goes up to $5 gallon, you will be spending $20 a week.

Is what you are considering really worth saving what will at most amount to a few bucks per month? My belief is that this modification can’t possibly be worth it. It would be easier and more effective financially to find another way to cut expenses from your budget. How is the weather stripping around the doors and windows in your home? How old is your refrigerator? If your refrigerator is old enough, a new one might pay for itself in energy savings. The same goes for laundry washers and dryers. How well is your home insulated? Have you ever thought about adding a layer of insulation in the attic or around your water heater? What about tinting a window of your home that gets a lot of sun exposure? Could you add a ceiling fan to your living room or bedroom? What about replacing light bulbs with ones that use less energy? Do you ever use your oven to cook for one person? Have you tried using a toaster oven or a microwave instead? Does your dishwasher have settings that can save energy? Can you turn off the heated drying cycle and let the dishes air dry instead? How about a programmable thermostat for your home? These are just a few ideas. Results will vary, but the initial investment for many of these types of projects will be much smaller.

The last time I heard of something like this was about 30 years ago when a ‘knowledgeable’ friend of mine bought a Wolseley 6/110 off another ‘knowledgable’ individual. The seller had discovered a cracked piston during a cheap rebuild and simply ommitted the piston and conrod, he also snapped the electrode off the sparkplug. The 6/110 uses a long stroke 6 pot engine and you could apparently only just tell it was 5 cylinder since the engine wasn’t carrying the compression of a dead piston.

To cut a long story short, the seller didn’t admit to any of this proclaiming that he thought it might be a bad plug but didn’t have the time to fix it…my friend, sensing an opportunity bought the car and drove straight to the nearest parts store, picked up a new plug and changed it there and then.

Obviously there was no improvement, so my ‘knowledgeable’ friend jumped back in the car and drove home, he was 2 miles from home when the fuel vapour in the empty cylinder and sump exploded and blew the oil pan off the car, wrapping it around the front cross member.

The local council charged him 200 pounds to clean up the oil blown all over the roadway and the front of the local firehouse. Extreme laughter was had at the time.

STOP ,thats all I have.

Why not do what you originally intended and replace the body panels on the 84?

That adjustable cylinder trick has never really worked. It would likely take some serious adjustments to get it to work as well as that Caddy engine and it was a lot of trouble. I really doubt if you can do better than they did.

There is a good reason why it was quickly discontinued and you can’t buy them today. The hybrid thing is a better idea and it is not a great winner either.

It didn’t work on the Cadillac 4-6-8 because the state of computing power for the engine management system was lacking in the late '70s.

That said, you’re dead wrong. There are a number of variable displacement vehicles for sale today- Honda Odyssey and Pilot are two examples I can name, and GM has a number of them I believe.

Just because GM’s variable cylinder system was so bad doesn’t mean that it doesn’t work. They also tried to give small cars a bad name with the Vega after all.

One of the simplest ways to adopt this idea to an existing car is to use all of the cylinders for a short time and then use none of the cylinders for a longer time while coasting and then repeating the cycle. This is called “pulse and glide” by people who set gas mileage records. When the engine is on, the throttle should be open to 75% full torque. A vacuum guage or scan guage II set to LOD mode can help you judge when your engine is at 75% full load. The best results come from the engine off during the coast but this is not always possible or practical except in manual transmission cars that don’t have power brakes or steering. Engine idling during coast still beats steady state cruising though.

Unlike disabling some of your cylinders, this does not reduce resale of your car and if you need to pass an 18 wheeler up a hill, you have all of your cylinders available.

Believe it or not, during the gas crisis of the mid-70s a kit was offered which replaced every other piston in the firing order with a dummy(open top) and spring loaded push rods for the correct cylinders. The valves remained closed and the pistons had no compression. I never saw one installed but it was a highly advertised in California. I couldn’t imagine a Ford LTD operating on a 151cid 4 cylinder, though. Not with the gear ratios common then, especially.