Show Posts

This section allows you to view all posts made by this member. Note that you can only see posts made in areas you currently have access to.

Topics - Roark

Pages: [1]
Engines / Injector question
« on: May 01, 2011, 01:39:53 AM »
Okay... Complete Noob here. You have been warned. :)

The engine is a Vidhata 1-banger water-cooled 1500 RPM.

Question: the injector has a threaded backshell which when removed shows a slotted adjustment locked in place with a lock nut ala a valve adjuster. A cutaway diagram I found on the net shows this screw sets the pressure on a spring which holds the injector pintle against the seat. Tightening this screw inwards causes the exhaust to clean up considerably. Loosening it yields somewhat dirtier deposits inside the stack.

What is this adjustment really doing??? Since fluid isn't compressible, I don't see it changing the timing, but I am willing to be called wrong. Or is this just setting the injector pressure and more pressure means better atomization?



Well, three years of lurking and I finally took the plunge. :)  Just for the record, when my wife got done screaming at me, I did the manly thing and liberally blamed this group. (She didn't buy it. Much. heheheh).

The object of my forthcoming divorce is a basket-case watercooled Vidhata VH4, 1-cylinder, 8 hp.  It was moving water at a fish-farm until it ran out of water (the water jacket on the engine is plumbed-in to the discharge of the pump. No thermostat. No screen. And the big pump isn't self-priming. Who DESIGNS this stuff?).  The engine isn't siezed, but it's clearly going to need a set of rings and related pieces. It's clearly been used hard. But I was looking for a project, and the price was right (free!), so it followed me home. The 6-inch centrifugal pump is going straight into the bin.  The base will need to be reworked. It'll need an intake, exhaust, and radiator.  But the basic engine seems very salvageable. All the major bits are still there. Unfortunately the crankcase looks like someone filled it with a mixture of grease and beer. So it's gonna have to come apart completely.

To my questions... and ANY comments/feedback/assistance will be appreciated:

Q1).  Anyone have a manual for this creature?
Q2).  Where are you guys getting parts in the USA? All I can find is Basant in India. Lots of lLister stuff, but nothing Vidhata!
Q3).  It appears the only difference between this motor and the 10 or 12 HP units is the bore. The stroke is the same. Anyone ever up/downsized one of these?

Thanks in advance for any pointers you can give.


Engines / Injector line residual pressure
« on: February 06, 2009, 02:40:54 AM »
Wierd question for the Oldsters in the group. :)

Between injection pulses, what is the residual pressure in the high-pressure line between the injection pump and the injector on a 'Roid?  Is this residual pressure fairly constant or does it vary with speed/load?

The reason I'm asking is this:  If there is a standard "residual" pressure in the lines between pulses, I can calculate the max pre-heat on the fuel in that line before it flashes to vapor.  Seems to me that heating it to just somewhat under the vapor-flash pressure would do great things for the atomization of heavy fuels.

Any comments from the Illuminati? :)


Engines / Deep Fall-back Scenario For Lister Twin?
« on: January 10, 2009, 03:31:54 AM »
A question for the ‘noodlers here:

Assume for a minute you’re running a twin-cylinder Lister(oid) that was made in the last 10 years or so.  Things are chugging along nicely after the mother of all hurricanes/a-bombs/ice-storms/tornadoes, etc.  You’ve got the house lit-up like a Christmas tree, you’ve got oodles of fuel, and your family is worshipping the ground you and Mr. Lister walk upon. Your neighbors love you because the tap works, the toilet flushes, and you've got ice to make margaritas.  Somewhere around midnight however, there comes a Really Major Problem and the lights all go kittywhumpus.  Something is dreadfully wrong with your genny.  In fact, the last time you heard noises like this, they came from your own stomach after you ate your sisters first casserole. :)

Some troubleshooting in the dark proves conclusively that Cylinder #2 is well and truly dead.  (Call it a cracked piston, bent rod, bad rod bearing, siezed injector pump, or a wheezy injector. Take your pick, or invent your own malady and season to taste). The important point here is it’s BAD and you do NOT have a spare for the bad piece, and you can NOT repair it.  Cylinder #2 is kaput, but Cylinder #1 is just fine.

The question:  Assuming your back was up against the wall and you had to pull a rabbit out of the hat, could you run this engine as a single-cylinder?  In other words, could you pop the rod bearings, slip-out the piston and rod assembly, spike the fuel rack on #2 to the closed position, (etc), pull the push-rods, and then fire this engine up and run it on just one cylinder?

From what I see, this seems possible.  But as I’ve never actually taken one of these critters apart and played with it, I’m completely guessing here.  But the answer is important to me.

Comments?  I’m interested in deep-fallback options for a Lister(oid) twin.  I've got a wife who turns into Sybil-At-The-Switch without hot coffee, and a son who will go nuclear without access to his Wii. :)  Sustainable, deep-fallback power is important, folks. :)


Pages: [1]