Turning a Twin into a Single

[BigGreen]

Yep, you convenced me that this is just another bad idea.
I'll look into buying another pulley.

How did you know you lost your prime? Do you have a pressure gauge installed?

Dave

[mobile_bob]

option B

buy a s195 changfa, and call it a day

you will get a more reliable, more efficient, better quality motor, for less money
that takes up less space, does not vibrate/shake or need a tone of concrete.

yes they are noisey, but that can be dealt with.



bob g

[SHIPCHIEF]

Bob is right, Have a small gen for small loads.
But you can run the 25/2 as a 2-speed with two sizes of gen pulley. Even then it might be more power than you need, but it will run fine, probably as slow as a standard 6-1 (600 RPM)
The oil pump delivers oil thru small tubes to the open cavity above each of the three main bearings.
Because these bearings are so large, the oil film pressure is rather low. a few drops every few seconds is enough to keep these bearings flooded, and the oil pump easily does that, even at very low RPM.
Rocketboy had an oil pump plunger spring failure which he documents on his site. The engine was not damaged even though it ran a whole day in this condition. The throw-off from the connecting rod dippers was appearantly enough?
As for the oil pump, I run a gauge on top. you are supposed to have a valve under it, and check it periodically, but not leave it 'on' or the pulsations will wear out the gauge. I don't have the valve. I also have to remove the gauge and squirt some oil in there to prime the pump before starting if the engine has sat any length of time.
Heck your supposed to open the crankcase door and squirt oil onto the main bearings and connecting rods before starting if the engine hasn't been run for a while....how long? I don't know. I do it if I haven't run the engine for a few months. I use that as a opprotunity to do an engine base inspection, check my magnets, door filter trap and look for cooling water leakage into the base. It's a good time to check the con rod dippers and the true oil level, also look at the cam idler gear backlash.
This is very basic. It is easy to inspect and easy to work on. You should have it set up so access to do the inspections are easy, that way you won't be tempted to skip doing those inspections.
Scott E

[Combustor]

          On the matter of oil priming before startup, with my 2 Listers (and any other engine with a manual priming lever) I find if I chech oil level and operate the pump for
a minute or so, then check oil level again, the level has dropped quite visibly, and I know the pump is working and the bearing cups are filled ready for startup. Regards,
          Combustor.                                                         

[jzeeff]

I find the idea of a variable number of cylinders interesting.   Could one put 2  engines in series (coupled shaft)  with a freewheel ratchet and then only start the second engine as needed?

[oliver90owner]

with a freewheel ratchet

You mean a clutch?

Been done before.

Motorcycles, dragsters.

Lister did it too, but without the clutch. Right up to 6 cylinders.

If it was a good engineering idea, Lister would not have made multi-throw crankshafts?  Just couled together more 6/1s?

Set up a big enough line-shaft and run several.  Have fun.

RAB

[Wizard]

with a freewheel ratchet

You mean a clutch?

Been done before.

Motorcycles, dragsters.

Lister did it too, but without the clutch. Right up to 6 cylinders.

If it was a good engineering idea, Lister would not have made multi-throw crankshafts?  Just couled together more 6/1s?

Set up a big enough line-shaft and run several.  Have fun.

RAB

What kind of design Lister did to couple or discouple cylinders as needed?

Cheers, Wizard

[oliver90owner]

They made singles, twins triples etc all with separate/common parts.  I was referring to a variable number of cylinders.   Solid crankshaft   As I said, without the clutch. Right up to 6 cylinders.

Next sentence said it all.  It was obviously not a good idea in Lister's view.  That is why they offered the engine line-up as they did, and did not offer a cobbled up pair of engines with a clutch, or any other alternative, between them.

Lister did it right and assured everything was lined up correctly - they put everything on top of thhe appropriate crankcase.

Reading this board, I doubt there are many, excepting a select few (proper) engineers, who could align two engines satisfactorily, let alone get them to run at those low revs in a con-joiuned arrangement.

RAB

[sodbust]

No problem with engine oiling at slow speeds.. The pump works better at 100 rpms than 1000, from my flow tests..

International Harvester,, played with allot of engines with on and off cyl action.. Dropping a bank when not needed for power..  Cant say it worked real well.  Or that the engines lasted well.

As for a ultra light load on a 2 cyl.. one has to factor that at a point of very low power output,, the engine almost becomes a hot air engine.. Just enough fuel to expand the air but not really make allot of fire or waste heat.

I do know that an uneven load on the crank would show up an ugly head after time by just working 1 side.  Old John Deere tractors started out with even fire with there 2 cyl engines.  They kept breaking cranks.. Went to odd fire and the cranks stopped breaking.

I would love my 28/2 to be an even fire, but know the history too well to mess with it.

sodbust

[Wizard]

Do you refer to even fire as firing both cylinders at same time every 720 deg?

As opposed to oddfire of firing one cyl the next cylinder 180 deg then 540 degrees then repeats using 180 crank?  Or Fire the cylinders alternatively every 360 (with 360 crank).

Cheers, Wizard

[NoSpark]

I have an 8 cylinder car with DOD(Displacement on Demand). The computer controls special lifters in 4 of the 8 cylinders, under the right circumstances it disables those 4 cylinders 1 at a time keeping either valve from opening after the power stroke trapping the exhaust in to act as a buffer and of course the injectors are shut off. It is totally seamless when it switches back and forth between 8 and 4 cylinder mode. I know this means nothing without computers and fast acting solenoids but they do it by keeping air from entering the cylinders therefore nothing to compress or pump.

[oliver90owner]

both cylinders at same time every 720 deg?

No, he said equal firing intervals - 360 degrees.

Regards, RAB

[sodbust]

The Listeroid I have the cranks throw is 180 apart,, but one cyl fires right behind the first power stroke.. Or the next 180 swing of the crank,,  An even fire would spilt the power strokes evenly..  or  360 apart..

It would be fairly easy to convert a twin to fire even by re pinning the cam lobes.. But then one would be looking at the problems John Deer had with breaking cranks I'm afraid.  That and drilling more holes in the cam shaft would surly make weak areas there.

sodbust

[Wizard]

I was just clarifying because even fire for 180 crank simply don't exist.  Crank position throws dictates the firing pattern.

That why I was asking which are you referring to with even fire on 180 or the 360 cranks.   Because there is two ways on 360 cranks.  Fire both cylinders at once or alterating every 360 degrees with 360 crank (both pistons moving together).

If 360 cranks breaking with the alternating fire type, I can understand but the question remains why did the 180 degree cranks did not snap in two in first place because it is also alternating fire.  Even this is uneven crank rotation (fire, 180 deg later, fire then every 540 degrees, repeat).   Curious and learning about that.

Wasn't JD using weak cranks with that 360 cranks and alternating?  Lister is not very high compression at all, just steady pow-pow all day long.

Cheers, Wizard

[Tom]

I had a '65 Honda 150 that had 360 deg crank. It had crank issues too, along with massive counter weights to deal with both pistons hanging off one side of the crank.