Preparing for extended run times

[rbodell]

I used a water heater thermostat glued  to the head with steel filled epoxy for an over temperature sensor.

Best Wishes,
Bruce M
Snowflake AZ
Metro 6/1

Is that actually on the head or on the cylinder. Any place I tried on the head is too hot for the water heater thermostat. I can find a place cool enough on the cylinder that I could use, but couldn't the head get too hot before tripping the thermostat on the cylinder?

Did you try it without the epoxy first to see of it was too hot? Maybe the epoxy reduces the heat

[BruceM]

The thermostat I used is adjustable and goes to 220F.  If you head gets that hot, you're in trouble.
I ground a flat spot and glued it down right to the head, inside the valve cover.

[SCOTT]

OK I have some more fuel consumption data. 

Gal used     time in hrs    prod in kwh     consumption gal/hr      gal per kwh     gallon yield in kwh
  4                 14.5         21.381                 .275                        .187            5.33

These figures are not as good as the other day.  I had similar results to these the day before, but can't locate the actual #'s
One problem I have identified is that the generator room itself is too hot.  I measured it last night of at least 112f and the gen head was almost too hot to touch.  I need to increase the cool air into the room, it is well insulated and pretty tight.  I opened the door a little and the voltage went up. I can see this in the data collected by the inverter.

Another problem is when I am running it at 380rpm, the belt slips and this robs power and is slowly chewing up the belt, there is a fine black rubber dust accumulating on the gen head.

I can also add mass to the gen head by adding a 13" pulley that weighs 80+lbs this should help carry the gen head through to the next combustion stroke.  Another option is to get a larger pulley, right now I have a 5" pulley I am thinking of getting a 6"

Thats all for now.

Scott

[buickanddeere]

  Adding weight/inertia to the generator will only make the slippage worse.
  The flywheel weight/inertia needs to be increased and the drive belt contact area increased 50+%.
  At 380rpm the power pulses are long intervals apart. Torque on the crankshaft at 380rpm is nearly double the amount of toque to make the same HP at 650rpm.
  Engine life may well be shorter runing this load at 380 rpm than it would be running at 650rpm. Wear is more than just the number of rotations. Wear varies with combustion chamber working pressure & temperature.

[rbodell]

The thermostat I used is adjustable and goes to 220F.  If you head gets that hot, you're in trouble.
I ground a flat spot and glued it down right to the head, inside the valve cover.

Where did you get it and what is the manufacturer of it?

All water heaters here have a 180 degree or so pop off valve. A water heater with 250 degrees in it would explode without the pop off valve. Everywhere I have looked has them up to 180 degrees but no more. Could it possibly come from something besides a water heater?

[carlb23]

Take a look at this page from grainger.  They have several limit switches for set temps and adjustable.  One of these should work for you.

http://www.grainger.com/Grainger/wwg/productIndex.shtml?search_type=brand&QueryString=WHITE-RODGERS&operator=refineSearchResults&originalValue=snap+disk&searchIndexId=0

[BruceM]

Thanks Carl.  I lost track of this thread and didn't see the question.  Carl is right, this was an adjustable snap-disk type thermostat from Grainger.  McMaster.com will not doubt carry something similar. 

Bruce M

[SCOTT]

I am still working out how to eliminate the belt chirp I am experiencing running my 6/1 @380 rpm with a pulley of 5”.  I have added a 2nd idler pulley to increase belt contact with the pulley and the flywheel.  The pair pinch the belt, pulling the upper run down and pushing the lower one up.  This helped but there is still a slight chirp, and eventually it will cause wear and failure.

I have a 12/1 sitting idle and I was thinking of borrowing one of the flywheels and adding it to the side opposite the starter.  Has anyone successfully added an extra flywheel to a lister type?  Before I did this I would verify that the borrowed flywheel is balanced, both the 12/1 and the 6/1 have internal counter balances.  I would also have to make a gib key long enough to secure both flywheels.

Ok so have at it, what are the downsides and upsides

Scott

[oliver90owner]

If a plain flywheel is used, that would be OK.  You will need two gib keys, one to secure each flywheel.  remember you are more than doubling the load on that side - the extra flywheel is further outboard from the bearing than the original.

The SOM flywheels are much heavier - are you using spoked flywheels now?  If so it might be better to change to SOMs.  A larger section belt may be a better option.

If I were adding extra flywheels I would consider an outboard bearing to help out with the extra loading, especially if it has TRBs.

Last point is how much cost efficiency are you achieving over a higher engine speed? You are admitting to needing a new belt in a fairly short period.  Would it cover the small extra fuel usage costs? The flywheel inertia is so much reduced at your lower RPMs, you may be better just upping the revs for extra inertia and allowing the governor to back off the fuel rack.(See B&D's post below).

Your engine will run extended hours at full rated speed - they were designed for that engine speed.  From what I can see you need more extensive data regarding output at normal speeds to get a reliable base line before you try to compare with different speeds, loads, fuels, etc.

There are several ways of doing this type of testing.  Alternatives could be long runs with lower precision measurements or shorter runs with precise fuel usage measurements and at very nearly constant load.  I would prefer the second as the experiments can be easily repeated to check for reproducibility, rather than the longer trials which may yield more or less output (kwh) over the time scale with all sorts of other altered parameters (ambient temps being one of them).

Whatever you do, keep it simple.  Changing too much at once nearly always leads to inconclusive results if the resulting changes are marginal.

Regards, RAB

[rbodell]

You could also tackle the problem from the other direction by cutting belt grooves into the flywheel.
In my situation, the chirping is definitively on the flywheel side even though the flywheel has waaaayyy more belt contact. Problem is that the contact is only on the flat crests of the belt unlike on the generator pulley which is properly grooved.

.... just a thought .....

Jens

I took delivery of my engine at a local machine shop where they had a fork lift to unload the truck with. When I got done I asked what it would cost to take a flywheel and turn a v-belt groove into it, since they had a lathe that would handle it. He said turning cast iron is not good. It could come out in chips or cause it to explode at a later date, especially if it was a poorly made casting such as these.

[SCOTT]

Oliver
I am runnung the engine at reduces speed because it is much quieter than at 650rpm, I am in a suburban area, to it helps a lot.  The flywheels I have on the engine now are spoked, the one I am considering adding is a stover type, not quote a slid flywheel, but heavier than the spoked.  As far as the belt, it is a "K" section, 8 rib,

Jens
I agree that if the flywheel were machined this issue may go away, I am afraid to get a quote from a machine shop for this, God knows what they would charge.  Has anyone had this done after purchase?

Rbodell
The metro engines have grooves machined into the flywheels, but you may be right I could see a shop here refusing to to this.

I was going to move up to a 6" pulley, but Mike no longer makes them.

any other suggestions?

[jtodd]

Oliver
I am runnung the engine at reduces speed because it is much quieter than at 650rpm, I am in a suburban area, to it helps a lot.  The flywheels I have on the engine now are spoked, the one I am considering adding is a stover type, not quote a slid flywheel, but heavier than the spoked.  As far as the belt, it is a "K" section, 8 rib,

Jens
I agree that if the flywheel were machined this issue may go away, I am afraid to get a quote from a machine shop for this, God knows what they would charge.  Has anyone had this done after purchase?

Rbodell
The metro engines have grooves machined into the flywheels, but you may be right I could see a shop here refusing to to this.

I was going to move up to a 6" pulley, but Mike no longer makes them.

any other suggestions?

Make a steel ring for the wheel, and heat-fit it on (or slightly notch the flywheel in a few locations and "key" the ring with a few beads of weld on the inside of the ring and squeeze it tight as you weld the ends together).  Then after the ring is secure, groove the ring.  Most big fabrication shops can roll something about .5" without a problem - you'll just need to do some careful measuring and planning.  It shouldn't alter the balance of the flywheel too much if you use good steel.

I have a ring around my stover-type flywheel, which was slotted with three "v" belt notches from the Lister factory across almost the entire width of the flywheel surface.  I wanted to use a serpentine belt, so I had to go this route.  I didn't groove the ring, since it seems to hold fine without it, but your mileage may vary.

JT

[SCOTT]

I have been thinking about this problem a little more.  I understand that the inertia of the flywheel going 380rpm is much less than that same flywheel going 650rpm.  So why would the system not benefit from an extra flywheel effect on the gen head, after all, the gen head flywheel is spinning at 1800 rpm. 

So by that logic I could add a flywheel to the gen head that weighs less than the engine flywheel and get more inertial “bang for the pound”  It has been said that the weight on the gen head side will make the belt chirp worse, but doesn’t the added flywheel help smooth out the power stroke?   What do you guys think.  If someone could explain the physics as to why the flywheel on the gen head would make it worse, that would be helpful

Scott