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Author Topic: 12-2 Air over Start  (Read 6173 times)

multis6

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12-2 Air over Start
« on: August 01, 2019, 10:16:47 AM »
 I have a Metro 12-2. that has become heaver to start each passing year (or I'm getting older).  Has any one set up there machine to start with air over the top of the piston to roll it over and get it started?
I have done a search but have not sorted through the 1000+ postings offered. 

38ac

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Re: 12-2 Air over Start
« Reply #1 on: August 01, 2019, 11:19:43 AM »
Not that I am aware of. All of the starters I have seen spin the flywheels. If your 12/2 is as I should be with change over valves adding air start will require some extensive changes to the cylinder head. If you have the 8/1 or 16/2 type heads with the plug you could go in through it. Be aware that starting an engine that way requires a large volume of air quickly so line and valve sizes must be sized accordingly.  But that brings another issue into play. Whatever passages you have between the valve and combustion chamber will serve to lower the compression in that cylinder. System s like you wish will have a one way valve very close to the cylinder for that reason.
What you propose is a lot of work and engineering to get around spinning the flywheels via electric or air motor with friction drive but to each his own ;D
Collector and horder of about anything diesel

BruceM

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Re: 12-2 Air over Start
« Reply #2 on: August 01, 2019, 02:37:57 PM »
I concur.

To do an air over starter, an intake valve in the changeover plug would be needed, as well as an electronic actuator and a very high volume solenoid valve to turn on/off the air, along with cam position sensor so that the valve timing could be managed for multiple rotations.  It would be technically challenging, and a cool retro-engineering project.

The far more practical and well proven approach is a starter motor with rubber friction drive, or a conventional auto starter motor on gear ring on generator.

I use a Gast 4AM motor with rubber roller friction drive, with a small air cylinder to press the motor/roller against the flywheel.  Some others have gone this route. This is practical for me since compressing air is a major job of my Listeroid. I also use air cylinders for an exhaust valve lifter and rack closer; my Listeroid is remote/autostart.

For most, an electric starter motor with rubber roller drive or gear ring drive on the generator would be the simplest and most effective.  It's well proven and low risk.


multis6

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Re: 12-2 Air over Start
« Reply #3 on: August 02, 2019, 12:10:27 PM »
Thank you for your input guys, I have a Gast 1550 air motor on my engine right now but the contact wheel is too large and it will not turn over the engine. I need to get a smaller and softer wheel to get the ratio correct.
 
I have worked with a 1 megawatt genset that had a 8 cylinder tug boat engine on it with an air start system.
It was the neatest thing to see it start. Flip the switch and the unit would crank over then fire up, with in 10 seconds it was producing power. As you said BruceM "It would be technically challenging, and a cool retro-engineering project." It is interesting to ruminate over the possibility of doing such a project.

Bruce the system that you have set up sounds interesting, Do you have any pics. that you could share to see how you have it set up? What size engine are you starting?

BruceM

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Re: 12-2 Air over Start
« Reply #4 on: August 02, 2019, 04:55:14 PM »
It was posted here in 2007, just before I completed the Picaxe based remote start/monitoring controller. Alas, you can't see the roller as it's facing the wall. It's about 2.25" diameter, 2" wide. That's a small oiler in the air line right at the motor.  The Gast 4AM motor does a good starting job on the 6/1 Listeroid even with unloaded air compressor but must have decompression.  The 12/2 is likely too big for it.  Someone tried a 6AM motor on a 12/2 and then switched to electric- the 6AM is a massive air eater, and plumbing for that much airflow from a tank will be a challenge. 

Pressure loss in the line significantly affects even the 4AM motor, which must have 1/2 hose supply, high flow solenoid, and short 1/2 exhaust to a 3/4 pipe tractor muffler (low back pressure).  The motor only sees the difference between input and exhaust pressures...a real eye opener when gauges are put on each next to the motor inlet/outlet under power. 

I'm not familiar with your Gast serial number.  Their standard product is in various family sizes, 1AM, 3AM, 4AM, 6AM.  They also made contract units of oddball models.  I use the 1, 3 and 4 AMs, I don't have the air supply for the 6AM.

McMaster.com has rubber rollers.  I used one with a 1 inch bore that fit a 1" OD shaft coupler and a fairly soft rubber for good flywheel grip.  Still using the original roller 12 years and 3K engine hours later.  A few starts daily for 20 minute runs when I'm working in the shop, for filling the 500 gallon air tank.  If I forget it shuts itself down after 10 minutes of no power or air load.  A pressure transducer and circuit can see the pulses of air pumping...and when the air unloader pilot valve has turned it off.
« Last Edit: August 02, 2019, 05:09:14 PM by BruceM »

Hugh Conway

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Re: 12-2 Air over Start
« Reply #5 on: August 02, 2019, 05:45:32 PM »
Not air, but a 12V starter/generator from a golf cart.......that's what I am using.
 
Got the idea and schematic from Veggie (IIRC) in one of his posts on microcogen. I think he has a youtube vid of his set-up in action. It has been in service for a couple of years now without any problems. Simple to fab a mount and operate. Not expensive. Starts the 6/1 after 2 rotations, would likely start a 12/2.
Veggie, how about re-posting some information here about your experience with the starter/generator?

I did use an automotive starter fitted with a friction wheel.  The wheel engaged with a hand-operated lever. That worked OK most of the time but was useless in winter weather when the flywheels on my 6/1 would have a thin coating of ice from freezing fog. The friction set-up is still in place as a back-up, but no longer used.
Lister did use an air start of some kind, I had come of the components installed in the COV in a spare head on the Dursley 6/1 that I have. The air start option was not intended for a 6/1, but the parts fit into the head.Took some research to identify it as belonging to  model. Posted some photos here a long time ago, but that thread got lost in a change to a new LEF format. Maybe some can add information about that air start system.
Cheers
Hugh
JKson 6/1  (Utterpower PMG ) Off-grid
Lister 6/1 Start-O-Matic engine......running with PMG
1978 Royal Enfield (glutton for punishment by Indian iron)
1963 BMW R-27 project

BruceM

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Re: 12-2 Air over Start
« Reply #6 on: August 02, 2019, 05:52:27 PM »
A lovely, simple solution that Hugh has, I must say.  I keep forgetting about that DC motor starter/generator option...which is a good one.


dkmc

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Re: 12-2 Air over Start
« Reply #7 on: August 04, 2019, 02:27:02 AM »
Hello MultiIS6,
I replied to the private message you sent me.
Check your Inbox, or email me direct......kliegelmachine@gmail.com

Dan

Bruce, are you located in the US? Just curious.
Your setup is very interesting, do you have a link to your build thread?
Thanks...
« Last Edit: August 04, 2019, 02:35:15 AM by dkmc »
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BruceM

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Re: 12-2 Air over Start
« Reply #8 on: August 04, 2019, 03:34:14 AM »
Dan, I'm in the White Mountains of AZ at 5600 feet elevation.

I posted that build here, roughly 10 years ago.  My "House of Lister" is located a few hundred feet away, over a hill...a location planned for the sound of most other generators, before I found out about the Lister CS. I have sensors for low/high oil, vibration, overtemp so it doesn't self destruct, since I can't hear it.  I think I'm still the only one with remote controlled Listeroid.  An oddity, putting a microcontroller on a 1929 design diesel, but it works for me and I use it regularly.



dkmc

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Re: 12-2 Air over Start
« Reply #9 on: August 04, 2019, 04:56:51 AM »
I think it would be worthy of a link or a new thread with the initial setup, modifications and any tips you have found with your experience over the years Bruce.

X2
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BruceM

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Re: 12-2 Air over Start
« Reply #10 on: August 04, 2019, 05:50:39 AM »
I'm in the midst of another project right now but I'll think about it.  It's involved, with custom, hand built point to point wiring for most; no PCBs at all, plus custom PicAxe basic software for their 40X2 processor. I've offered the schematics and software here before, and nothing came of it...it's just too much technical work for most.

The design is also odd due to a rather extreme EMC design effort to keep high frequency emissions of the clocked processor off of all the attached wiring. The processor(s) are in die cast aluminum boxes, with filtered DB connectors and bandwidth cutoff of a few KHz and highly filtered power. The processor drives nothing directly due to this filtering, so all outputs are buffered. Communication is my own design, opt isolated current loop at 600 baud over 400 feet of Cat5.  (Nothing fast needed for engine control/monitoring of with only a handful of bytes of digital data.)

A more conventional design with the processor mounted directly on the interface board would be much simpler and might have wider appeal. Again, special for my own needs, and it does just what I need. 



 

veggie

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Re: 12-2 Air over Start
« Reply #11 on: August 04, 2019, 05:33:39 PM »
The golf cart Starter/Generator solution works well.
Here's the one I built a few years ago.
Turns the engine past compression without much effort.
Then charges the starting battery after the engine is running.


https://www.youtube.com/watch?v=qbcbuygYJdM

more on that project here...
http://www.microcogen.info/index.php?topic=3096.0
« Last Edit: August 07, 2019, 01:32:51 AM by veggie »
- 6/1 GM90 Listeroid - Delco 33si Alternator
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dkmc

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Re: 12-2 Air over Start
« Reply #12 on: August 04, 2019, 06:30:56 PM »
The Youtube link says 'video unavailable'

EDIT: This one works
https://www.youtube.com/watch?v=qbcbuygYJdM
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Hugh Conway

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Re: 12-2 Air over Start
« Reply #13 on: August 04, 2019, 10:51:31 PM »
Thanks Veggie for posting this starter/generator information again.
Yours was inspiration for my set-up. It is not as neat as yours, but works just as well, has hundreds of trouble-free starts under its belt now after several years in service.

It is a really good solution to motorized starting and does not require any specialized machining, welding, etc.
Made my set-up with a cordless drill, a hacksaw, a file and some Aluminium channel. It is belted on the same side of the engine and sits between the engine and the PMG.
The additional load caused by being continuously belted up seems to have no discernable difference on the engine loading while charging our off-grid battery bank.

I think the information in this thread (and the whole microcogen thread) might well be posted on the WOK.
Thanks again for your original, very informative posting on microcogen.

Cheers
Hugh
JKson 6/1  (Utterpower PMG ) Off-grid
Lister 6/1 Start-O-Matic engine......running with PMG
1978 Royal Enfield (glutton for punishment by Indian iron)
1963 BMW R-27 project

multis6

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Re: 12-2 Air over Start
« Reply #14 on: August 05, 2019, 11:08:52 AM »
Well this is the 3ed time trying to get a reply out......
Bruce it sounds & looks like you have spent quite a bit of time and thought building your system. Well done & thanks for the pics.
It is interesting to see how individuals have taken the basic engine and adapted there own technologies to fit there needs.
Talk about basics...... I crank my 12-2 Metro 5 revolutions then stomp on a peddle to pull a string to swing the decompression lock out of the way, then on the 6th rev. I push it through the compression stroke and off it goes. So yes a more elegant starting method is due.
It looks like a bit more work with the Gast air motor (assist) will be the way to go for now.