Author Topic: cs valve retrofit  (Read 5025 times)

biobill

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cs valve retrofit
« on: October 10, 2006, 03:27:39 AM »
has anyone attempted to install a cs valve assy in a head that did not come with it? my (limited) understanding is that it raised the compression ratio for cold weather starting. my DI 6/1 metro starts great in the cold but at 29F the other morning my new (l/t 8hr) IDI showed some reluctance. i see parts are available from anand. does anyone know if it would be a "screw in" opperation or would there be machining involved, or would it be absurd to attempt. would it be significantly benificial? i should be getting my firewood in instead of messing with these darn things but i think you know how that goes. any time saved would be appreciated. oh yea, the subject would be a metro 6/1
Off grid since 1990
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listeroidsusa

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Re: cs valve retrofit
« Reply #1 on: October 10, 2006, 04:53:39 AM »
Yes, the c/o valve is a very easy retrofit. Unscrew the blanking plug. Your C/O valve will have a 2 piece hemispherical chamber. Place the copper O ring into the hole in the head and seat it, place the loose half of the c/o section in over the copper O ring and finally screw the handle portion into the head. Make sure the handle is unscrewed to the out position and torque the retaining nut in place. Screw the handle in for high compression and out for low compression. At the halfway point the compression will be relieved to the atmosphere. (Helps clean the carbon out when operating the valve) Its now ready to run. Some do have a tendency to back out on their own so seat the valve firmly either in or out.

Mike  Montieth
Listeroids/USA

listerdiesel

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Re: cs valve retrofit
« Reply #2 on: October 10, 2006, 11:26:18 AM »
There are a couple of snags with using the changeover valve as a decompressor, the biggest problem is that the pressure relief hole is not very large, so any unburnt fuel and soot gets forced through the acme thread of the valve, eventually seizing the thread. Opening the relief hole out does help a little, but it isn't a great idea.

The other problem is that opening the valve with the engine running can and does cause burning or chipping of the valve spindle seating, which is VERY small in area. Use it as little as possible to extend the life. Not so much of a problem on starting up when going from one compression setting to the other, but is a problem when the engine is hot. We have had a few built up with weld over the years and reground in a standard valve seat grinder.

Better to use the decompressor that comes with the engine, or fit one if it didn't.

The basic concept of fitting the valve in the first place is a good one, just needs to be used correctly :-))

Peter

biobill

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Re: cs valve retrofit
« Reply #3 on: October 10, 2006, 02:14:05 PM »
so should i start on high compression until warm? hot? then stop engine and switch to low compression? is there a danger of running too long on high compression? (obviously there must be, but at what point should hte change be made?) and....does anyone supply a retrofit "kit" so i don't end up with 3 extra gizmos but short one critical doodad? thanks
Off grid since 1990
6/1 Metro DI living in basement, cogen
6/1 Metro IDI running barn & biodiesel processer
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BruceM

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Re: cs valve retrofit
« Reply #4 on: October 10, 2006, 03:22:54 PM »
My Metro 6/1 (IDI & no CS valve) was tough to start; impossible on cold mornings here at 5600 feet elevation.

I added the utterpower glow plug and it started on the first compression stroke. There's no waiting for heating, just turn on the plug and crank, release the decompression valve, and bingo, she's running.

This is even more impressive as I later learned that my cylinder wasn't honed, and also the head clearance was WAY too large, so compression was way too low.  Fixing these turned it into a great starter without the glow plug being lit-  but I'm very glad to have it there for an extra cold winter morning.

If someone gave me a CS valve tomorrow I wouldn't install it.

Best Wishes,
Bruce M

Quinnf

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Re: cs valve retrofit
« Reply #5 on: October 10, 2006, 04:05:51 PM »
Biobill,

A few other folks have done what you're contemplating and ended up regretting it.  The original Lister CS had a 15:1 compression ratio when the valve was in the "run" position, and a 19:1 ratio when in the "start" position.  The Indian Listeroids split the difference and run 17.5:1 for all conditions.  If you install a cs valve in an Indian engine that wasn't intended for one, you might find, as have others, that the engine won't run well unless the valve is in the "start" position. 

The CS head was Lister's way of setting their product apart from the others of the day.  It was patented and advertised extensively.  One would think that if the CS valve was such a great idea, once the patents ran out, other manufacturers would rush to offer CS valves, but that didn't happen.  And even Lister abandoned the CS valve when they introduced the 8/1 and (I think) 10:1.  David Edgington's book has a good description of the ins and outs of the CS valve. 

There are other ways to get a diesel engine to start in cold weather, and one is to raise the compression ratio to a value that is more representative of what you will find on other engines.  15:1 is VERY low.  Typically modern diesels run from 17:1 to 19:1.  Some small direct injection marine diesels I've seen run 22:1 and 23:1. 

Electrically operated glow plugs are universal in indirect injection diesels (like most Lister/Listeroids) these days.  Direct injection diesels use induction air heating elements.

Quinn
Ashwamegh 6/1, PowerSolutions 6/1 "Kit" engine, and a Changfa R175a that looks like a Yanmar I once knew

listerdiesel

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Re: cs valve retrofit
« Reply #6 on: October 10, 2006, 05:20:44 PM »
Going on from Quinn's post, you must also remember that at the time, indirect injection was the only game in town with the technology of the day. Many indirect swirl systems were patented, Acro, Whirlpool, Ricardo Comet etc., once injector technology had reached a higher level of pressure and atomisation, the need for the higher compression ratio vanished, followed eventually by direct injection. Lister and others stuck with indirect injection until very late in the day.

The other added help was the cold-starting position on the injection pump rack which helped a lot.

The side benefit if indirect injection is the comparatively 'quiet' firing, something that was a problem with direct injection diesels for a long time, especially small, high-compression automotive engines with high advance positions on the fuel pump.

Peter

cujet

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Re: cs valve retrofit
« Reply #7 on: October 10, 2006, 07:53:14 PM »
My engine makes 14.75 to 1 compression with the valve in the run position. It makes 17.65 to 1 with the valve in the start position. Both of which are too low. However my piston to valve and piston to head clearance is as close as I dare, with 0.045 inches piston to head (bump clearance).

Notice that I mentioned piston to valve? That is because as you start removing cylinder base gaskets to decrease bump clearance, the valve clearance decreases too. This makes the manual compression release less effective, as you now can only open the exhaust valve 0.045 inches before the valve hits the piston. This makes crankover very difficult.

What I discovered is that the internally machined pre combustion chamber is quite a large volume on the Listeroid heads that I have seen. This, I believe was done to accept the screw in plug with a FLAT machined end. The change over valve has a concave surface, lowering the maximum attainable compression ratio.

Chris
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aqmxv

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Re: cs valve retrofit
« Reply #8 on: October 10, 2006, 08:34:02 PM »
Cujet - you may well be right.  It's the sort of change that the Indians would make without telling anybody.  How deep are your valves seated in the head?  You might be able to get some clearance by cutting the seats deeper.

6/1 Metro IDI for home trigen

biobill

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Re: cs valve retrofit
« Reply #9 on: October 12, 2006, 01:01:25 AM »
really appreciate everyones input. i ordered george's glowplug set up this morning, seems like a more positive solution to my -10F problem. probably should have ordered the thermostat set up too but thought i'd see if i could craft (cob) one together myself. anyone see any problem with an inline unit mounted close to the head?
Off grid since 1990
6/1 Metro DI living in basement, cogen
6/1 Metro IDI running barn & biodiesel processer
VW 1.6 diesels all over the place
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Needs diesel lawnmower & chainsaw

BruceM

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Re: cs valve retrofit
« Reply #10 on: October 12, 2006, 01:39:33 AM »
Hey Biobill,
Just though I'd add that if you haven't done it yet, I'd definately suggest checking your head to piston bump clearance.  Some small bits of lead solder will work, then measure with your micrometer.  Getting this set right makes a huge difference in starting.  Not too many folks have reported it being within spec. from the factory, mine included.

When adjusting the bump clearance via paper shims under the cylinder, it saves time to cut out some sheets of typing paper as gaskets, and put them on top.  Manilla folder is good for a thicker gasket. Then you can reduce the head clearance in 0.003 inch increments by just lifting the cylinder a bit and peeling off the top sheet.  Otherwise you've got to lift the cylinder off the piston each time.

Best Wishes,
Bruce M
« Last Edit: October 13, 2006, 04:28:29 PM by BruceM »

biobill

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Re: cs valve retrofit
« Reply #11 on: October 15, 2006, 12:22:33 AM »










Thanks for the  advice Bruce, I just wish that I had asked a couple days earlier. Had thought that the CS was not going to be a reliable cold starter and so put it in the basement for furnace & battery charging duty with the DI to power my unheated barn. But with a GLOWPLUG - wow , power on demand. Unfortunetly this means I have to swap these monsters around, again.
Haven't checked the deck height on the CS yet, will have to do that during install. My DI was way too tight, piston  leaving marks in the small amount of soot that had accumulated after 2hr running. Factory gasket kit includes a selection of various sized base gaskets so it was easy to correct.        Bill















Off grid since 1990
6/1 Metro DI living in basement, cogen
6/1 Metro IDI running barn & biodiesel processer
VW 1.6 diesels all over the place
Isuzu Boxtruck, Ford Backhoe, all running on biodiesel
Needs diesel lawnmower & chainsaw