Running on Three

[OLD DODGE]

Ouch!

[Dodgeb4ya]

I have done that on my big trucks with that twin carb big Moly Block engine to sync the throttle linkage and the engines don't shake at all. You can close the throttle plate 100% @ idle on either front or rear carb and the engine speed drops maybe 100 rpm and the engine just "drones"- no violent shaking. These bigger engines have a lot of spinning mass weight- heavy flywheel/ fully counter weighted crank to help make them smooth running and long life engines. They will easily idle down to 300 RPM or lower too.

Great picture find!

Bob

[Merle Coggins]

It looks like the engine is connected to a dyno, so it's probably under a fairly heavy load for this test. That would explain the vibrations. At idle there may be no noticible effect. but at WOT on one carb and under a load I'm sure it wouldn't be happy.

Merle

[Dave72dt]

I had an old 6 cyl Continental in a forklift that would run on about three when wet and as it dried out would pick up the other cylinders. Also 2 cyl Onan engines that would run on 1, albeit poorly, usually meant they had a head gasket blown.

[greg g]

Uh, I have to disagree with the the assumption that the rear cylinders are not getting any fuel. There is a manifold balance tube between the front and rear castings. I would thik that with the fuel shut off to one carb that the farther away cyliders would still pull fuel air mix to them. It may have been a smaller and leaner charge but it still would get there.

A better test would have been to shut down ignition to the cylinders. And isn't that similar to the NEW fuel saving technology ( that was introduced back int he 70's by Caddilac) that shuts down cylinders when engines are in cruise mode? Or are the new engines doing it through manipulating fuel injectors.

And weren't some engines modified into air compressors by putting fittings to replace the sparks plugs of a couple two three cylinders????

[Don Coatney]

Greg;

It has been my experiance that when I disconnect the throttle linkage from one carburetor and close the butterfly of the disconnected carburetor that there is a gross imbalance in the intake manifold and my engine stumbles and barely runs when I open the throttle butterfly of only one carburetor. I was surprised to learn this as I originally thought like you that one carburetor on a dual manifold should work but that is not the case.

[MBF]

Greg-you're right. I've seen compressors built on Model A Ford, and Chrysler flathead sixes where half of the cylinders were strictly compressor, and the other half used for power. Pretty unique sounds. Mike

[HanksB3B]

about those big stupid decals. At least I only have one air cleaner.

Hank

[Dodgeb4ya]

Greg;

It has been my experiance that when I disconnect the throttle linkage from one carburetor and close the butterfly of the disconnected carburetor that there is a gross imbalance in the intake manifold and my engine stumbles and barely runs when I open the throttle butterfly of only one carburetor. I was surprised to learn this as I originally thought like you that one carburetor on a dual manifold should work but that is not the case.

Don, you are absolutely correct. I have acheived the same weak engine performance by cupping my hand over either front or rear carb-no air can flow through it so the engine runs only on the other carb. The engine will idle and rev up without shaking violently but is very anemic .

Bob

[Don Coatney]

Greg-you're right. I've seen compressors built on Model A Ford, and Chrysler flathead sixes where half of the cylinders were strictly compressor, and the other half used for power. Pretty unique sounds. Mike

I have also seen the 1/2 air compressor engines. Main difference in what we are talking about is on the hybrid air compressors the intake manifold (with the air fuel mixture) is not connected to the cylinders used for compressing air. The compressed air cylinders use fresh atmospheric air through a seporate manifold. Can you imagine the explosive nature of a tank full of compressed air fuel?

[Dodgeb4ya]

Have seen chevy 348's used as both water and air compressors.

[Don Coatney]

Have seen chevy 348's used as both water and air compressors.

How do you compress water?

[Dodgeb4ya]

How do you compress water?

Uh, Didn't state..

Water pump...Not water compressor.

Edited December 20, 2010 by Dodgeb4ya

[Don Coatney]

Uh,

Water pump...Not water compressor.

Thought that might be the case:D

[Jim Shepard]

I had an old 6 cyl Continental in a forklift that would run on about three when wet and as it dried out would pick up the other cylinders. Also 2 cyl Onan engines that would run on 1, albeit poorly, usually meant they had a head gasket blown.

I had a three-legged Border Collie once who loved to trail ride with me. She'd get a thorn in one of her remaining legs and would run along side of me and my horse on two legs, any of the remaining two - it didn't matter. Front two, two on one side, or diagonally... (sorry for the highjack...).