idea, 4 cylinder to 2 cylinder engine conversion

[Accord_Guy]

Thanks for that Saand. I stopped playing around with my 2 cyl as winter came and haven't really started up yet as I've got another 2 projects to complete before getting to this one.
My 2cyl Accord is a 94 and is OBD1 and aside from the CEL Check Engine Light (which has not come on by the way) to report it's functioning I'm pretty much flying blind. I've bought a 95 that I want to do my final mods to but again it is only OBD1 so I will need to convert it to OBD2 so I can get all of the cool reporting including MPG...

Before I do the final conversion I will be all of my trials on another one which is a 96 (it is OBD2).

OK, so this is what I am planning.

With my trusty OBD2 logger I will do consumption and usability tests on 3 combinations of cylinders (1and4, 2and3, and either 1and3 or 2and4). The crank on the accord has 1and4 up while 2and3 are down, so 1and3 or 2and4 should give the same result. These will be done simply removing the injectors. Whichever configuration gives me the lower consumption and better usability I will build into the final mod. What I am looking for is for my ECU to be able to run in closed-loop mode and for the CEL to remain off.
If my ECU is able to go into closed-loop mode then I know that my engine is running efficiently and all I've got to do from then on is use the power I've got efficiently.

The final mod -
I will remove the rockers as previously described simply MIG welding the oil passages closed, and remove the pistons installing hose clamps on the bearing surfaces to close out the oil passages on the crank.

Then I will do a full range of tests utilising my trusty OBD2 logger and document the lot.

UNDERSTOOD - I know that the performance will not be optimal and that it will take me longer to pull away from the lights. I recognise that I might have to go up a size on my injectors as the 2 cylinders will need to be able to work harder than before.

I'll keep you posted.

Accord_guy

[Accord_Guy]

Originally Posted by Frank Lee

Mine wouldn't start on 2 and I'd be surprised if any 4 did.

Reply for Frank_lee. Hey, I lucked in with my 5th gen Accords as the ECU seems to be just dumb enough (does not have knock sensors...) that it doesn't detect any wrongdoings and I can play around with it to my heart's content. I went to my trusty 2cyl a couple of weeks ago and started it after sitting in the field all winter and it started on the first try just the 2 cylinders.

There is still hope for this mod.

I'll keep you posted

Accord_guy

[theycallmeebryan]

Simply disconnecting the injectors and spark plug from cylinders is not going to give you much of a gain. Your engine still has valves opening and closing, thus the 2 pistons not in use are still acting as an air pump, which is an inefficiency. Even if you remove the rocker arms and the valves stay closed, the 2 unused pistons are still moving up and down against vacuum. Think of it as the plunger in a syringe, when you plug up the opening, its difficult to move the plunger in any direction after a point. This added resistance transfers into a loss of power which requires more fuel in the other cylinders to compensate.

In order to reap the full benefits of this idea, not only will you need to remove the rocker arms on both the intake and exhaust, you'll have to disconnect and remove the rod from the crank and piston and remove the pistons as well. Then, the crank will need to be rebalanced.

A lot of work and costly for sure. I'd rather spend my time swapping in a more efficient 2 cyl engine (maybe even a small diesel), getting an adapter plate made for the transmission (if need be), try to lighten the car, and work on aeromods.

[zonker]

Originally Posted by sarguy01

Instead of killing two cylinders, why can't one destroke an engine and not have to mess around with the balance, valves, etc, etc??

Would the difference in gas mileage in between say, a 2.0L and a 1.5L be significant enough to pay for the cost of the crank and other machining required?

probably not, unless you found a match with interchangeable parts to make the swap work.

For example, a 2.0L ford escort/focus zetec and spi motor can be destroked to 1.7L by using a 80's ford escort CVH 1.6 crank (i forgot what they used for rods)

I do have another thought on this... the reason for decreasing motor displacement is to operate the motor at a higher load so there is less pumping losses, so instead of cylinder disabling or de-stroking a motor, how about grinding a cam that takes advantage of the atkinson cycle for the reduction of pumping losses.

What I'm referring to is have the intake duration of the cam moved so that the intake valve stays open a percentage of the compression stroke to reduce engine vacuum and the air/fuel cylinder fill that enters the cylinder prior to compression/ignition, making the engine act as a smaller displacement motor.

I'm thunking of trying this with my 2.3 mustang... milling the head for high compression and adding a custom grind camshaft that will promote a late closing of the intake valves.

How this affects the operation of the vacuum dependent accessories (brakes, cruise control, hvac vent doors) remain a mystery. I have located a manual brake conversion kit ($70) in case it does affect brake boost. I may have to run a small vacuum pump to control the other items.

[euromodder]

The upcoming generation of VW's direct-injection 1.4L TSi Euro 6 petrol engine, will feature dynamic cylinder deactivation, based on engine load and driving style.
Between 1000 and 4000 rpm, and between 25 and 75 Nm of torque, it'll shut down 2 cylinders - that's 70% of the time on the NEDC.

It's expected to debut in the VW Polo, and to later appear in the Golf VII.

I hope they'll also do a CNG version - with the distances I do, electrics are out for the time being.

[Accord_Guy]

Hi guys, it's been a while. I took the engine apart yesterday as I was getting weird and unpredictable results from the 2 outer cylinders... An autopsy of the poor thing revealed that I had a bunch of bent valves and scored cylinder walls from the previous owner. So now I have a new head and and I can resume my mods. I need to modify my fuel rail to block off the 2 injectors, remove the rockers and balancer timing belt and we're off to the races... so to speak. I'll post pictures and further info as it becomes available.

[Accord_Guy]

Further to my last post wrt removing 2 cylinders...
Rebalancing cranks and destroking... are all expensive engineering feats and may work very well, but then as one of you guys mentioned why not simply replace the engine with a smaller more efficient one. Well all that costs money.
My whole aim here is to do a simple mod that costs me zip!
I have seriously spent zero dollars thus far doing this mod and am looking to reuse all gaskets... even the head gasket - I've done it a couple of times before with fairly good results. I may be dreaming but if this works it'd be a great mod for someone like me who does 50+ kms per day on nice flat low speed highways. And if not... well, I like playing around with engines and what-not and besides it keeps me out of the Bingo halls LOL
I'll keep you posted.

[Accord_Guy]

It finally happened, I got it done.
Over the last week I completed the mods on my Accord and successfully removed 2 cylinders and conducted my first tests last night.
The engine starts first time and idles well enough without even cranking up the idle.
This is what I have done thus far:
1. Removed the A/C (what's the point trying to squeeze extra kms out of the tank while running the A/C right!?)
2. from underneath, I removed pistons 1 and 4 and cut the end of the con-rods off then re-attached the ends with bearings to the crank to block the oil passages and help balance the crank without the removed 2 pistons.
3. I cut up and ground the rockers efectively making collars to block the oil passages on my rocker rails so that the camshaft only opens and closes the valves on cyls 2 and 3.
4. I made up new gaskets for the throttle body and intake manifolds to block out the no. 1 and no. 4 intakes.
5. I plugged up the fuel rail where the injectors for cyls. 1 and 4 are and put dummy loads in the place of the injectors so that the ECU doesn't complain.
6. I reused my head gasket and all other gaskets and seals... and even reused my old oil and coolant.

I had a lot of fun doing all of this.

The end result - it idles a little lumpy and it seems to accelerate very well in static tests.

Next tests, the road test and then a consumption test.

I'll also try to upload some videos.

Any guesses as to whether this will yeild any benefits and to what extent?

Accord Guy

[Frank Lee]

Perhaps up to +20% fe i.e. 30 > 36.

[RunningStrong]

You're mad.

I hope this works out and you get some great FE improvements and a usable car.