Hypothetical cylinder deactivation question

[2000neon]

I have been thinking about the idea of cylinder deactivation, and I understand that the only successful route to take is by disabling all of the valves to basically make an air spring with the "trapped" air, as well as cutting off fuel.

I was thinking about fully deactivating a cylinder, not just at cruising speed. The car in question is a 2000 dodge neon, with a 2.0 liter, 4 cylinder, 16 valve motor. The idea that I'm thinking about would be to remove the rocker arms for the valves in that cylinder, and then pulling the electrical connector to the injector.

By removing the injectors, it would disable the valves, and the springs would just keep them closed, and removing power and/or ground to the injector, the fuel supply would be cut off.

In theory, this should work. The cylinder pressure from the trapped air would keep enough pressure on the rings to prevent excessive oil burning.
The lack of air into the exhaust would prevent faulty O2 sensor readings.
If this was done for cylinders 2 or 3, there shouldnt be too bad of any "hot spots" by the lack of combustion, as the aluminum head and coolant flow should keep things moderated.
A lock of power shouldnt be too much of an issue, the motor would still basically be a 1.5 liter with a heavy rotating mass And at 130 hp, cutting off 25% would still leave 97.5 hp, which would be enough for basic daily driving duties.
Balance could be an issue, although with the deactivated cylinder still being there, the piston and rod would keep things in balance except for the "kick" from combustion. - but lets be honest, these neon motors all shake a lot anyways

The only thing that I can't picture in my mind is the actual rocker arm setup. The majority of my engine experience is with older Chevy motors, with a very simple pushrod design, which would allows for extremely removal of a rocker, but I dont really know how these neon's valvetrains are set up. Also, do the neons use a shaft mounted rocker? Would it be possible to remove only some of the rockers?

What do you guys think? Is it worth the cost of a valve cover gasket and some time?

[2000neon]

I do understand that this would probably throw the check engine light due to a cylinder misfire, but would that result in any fuel changes?

[t vago]

For the Neon 2.0 SOHC engine, the rocker arms are mounted on pivot shafts that are above the cam. Hydraulic lash adjusters are built into each rocker arm that link the arm to the valvestem. There are separate pivot shafts for intake and exhaust. The pivot shafts are also part of the oil supply, as they supply pressurized oil to the lash adjusters in the rocker arms. The intake rocker arms each control two valves, while the exhaust rocker arms each only control one valve. This implies that, for each cylinder, there are two exhaust rocker arms and only one intake rocker arm.

Now, you could remove the rocker arms for a given cylinder, but then you'd have to put in some sort of sleeve that would prevent your oil supply from spewing out the holes in the pivot shafts and starving the remaining valvetrain components.

As for engine longevity? Eh. Your oil pump might not like the resultant vibrations from having one cylinder become dead, meaning that the gerotors might crack apart.

[Frank Lee]

Try it- it probably won't even start, if it's like my 2.3 HSC on 2 cylinders.

Oil pump fall apart from vibrations? Really?

[t vago]

Oh, I'm sure it'll start. This engine is fairly stout. I once hydrolocked one of these engines, and could get it to start with only 3 working pistons. Surprisingly, it ran pretty good, too... even after the dead piston got chewed up by the crank and allowed oil to get sucked into the intake manifold.

[2000neon]

As for longevity, the motor already has 200 000 kms on it, and the body has only got about 1 summer left in it..

I am intrigued about the oil though, is there an actual oil feed line, do you know if it would be possible, or reasonable to actually take care of the oiling issue?

[t vago]

Originally Posted by 2000neon

As for longevity, the motor already has 200 000 kms on it, and the body has only got about 1 summer left in it..

I am intrigued about the oil though, is there an actual oil feed line, do you know if it would be possible, or reasonable to actually take care of the oiling issue?

Yah, it's the pivot shaft.

If you remove the rocker arms, you'll see holes in the pivot shaft that feed the rocker arms. If you're going to leave the arms off, you'll need to plug those holes. Otherwise, your remaining rocker arms will rather quickly fail and your engine will run like garbage until it dies.

[2000neon]

Hmm, okay then, does it all feed inline? Like for example if I removed the rockers for cylinder number 3, and plugged the oil hole, would cylinder #4 now not receive any oil? Or are they all separate.

[t vago]

This picture should help.

If you remove the rocker arms for #3 cylinder, you'll need to install sleeves over the pivot shafts to replace the rocker arms. Otherwise, the oil supply will just shoot out the bare holes in the pivot shafts where the rocker arms used to be, and you're going to end up starving the other valvetrain components.

[2000neon]

Sweet thank you, that is a huge help. So the oil supply is right down the middle of pivot shaft.

Seeing as my brother is a machinist, I wonder how tough it would be to make some sleeves to clamp over the oil ports and actually seal.