Half Scale Ford Quadricycle Engine

[cfellows]

Chris, 1/32" venturi seems way too small for an engine that size. I would think a 5/32" or even 3/16" bore would be more to its liking.

Chuck

 

[vascon2196]

Thank you Chuck...I sent you a PM several weeks back...I must have done it wrong. I was going to ask you about your vapor fuel tank.

I tried to make my own but it did not work...probably because the intake hole was too small.

 

[radial1951]

The engine runs strong without the carb installed. With a wide open hole I squirt starter fluid directly into the intake and it runs great. If I stuff a gasoline soaked paper towel into the intake the engine runs strong.

Once I install the carb and add starter fluid/gas it does not run. I'm thinking it needs more air. When I cut all the original numbers in half to make my half-scale version perhaps the air hole was not supposed to be cut that much.

A co-worker of mine has built several Red Wing engines and said his 1.25" bore has a 3/16" hole in the carb where I have about 1/32".

I'm not just sharing this information to vent my frustration (maybe a little), but also for others who are having issues with their small gas engines.

He also said the Flywheel should have a counter-weight.

Hi Chris

I couldn't agree more with Chuck, needs a much bigger bore in the carby.

How did you end up with a 1/32" diameter venturi? There must be an error, surely the full size engine doesn't have just a 1/16" bore in the carby, more like 3/8"-1/2"dia I would think. I wonder what George DeAngelis' drawings show for the carby?

Terminology is important here, I assume we are talking about the main air intake into the engine? If so, your clue is that the engine seems to get enough air when you take the carby off. The Walbro type carbs on power garden tools (and model aircraft engines) have around a 1/4"-5/16" dia venturi, and a built-in fuel pump, maybe you could disguise one in a polished brass housing...

Yes, if Henry was building his engine now, he would have a balance weight on the flywheel. But it was 1896... In fact he probably wouldn't have both pistons going to TDC together, but he thought having even power pulses was important, hence the massive flywheel to try and smooth things out. BMW got the same result by going to a flat twin. Harley Davidson still don't worry about even firing, thank goodness, that's why they sound so great!

Regards, RossG.
radial1951
_____________

 

[vascon2196]

Hi Chris

I couldn't agree more with Chuck, needs a much bigger bore in the carby.

How did you end up with a 1/32" diameter venturi? There must be an error, surely the full size engine doesn't have just a 1/16" bore in the carby, more like 3/8"-1/2"dia I would think. I wonder what George DeAngelis' drawings show for the carby?

Terminology is important here, I assume we are talking about the main air intake into the engine? If so, your clue is that the engine seems to get enough air when you take the carby off. The Walbro type carbs on power garden tools (and model aircraft engines) have around a 1/4"-5/16" dia venturi, and a built-in fuel pump, maybe you could disguise one in a polished brass housing...

Yes, if Henry was building his engine now, he would have a balance weight on the flywheel. But it was 1896... In fact he probably wouldn't have both pistons going to TDC together, but he thought having even power pulses was important, hence the massive flywheel to try and smooth things out. BMW got the same result by going to a flat twin. Harley Davidson still don't worry about even firing, thank goodness, that's why they sound so great!

Regards, RossG.
radial1951
_____________[/QUOTE]

Hi Ross,

Attached is the original full-size carb drawn is Solid Works. It is slightly different than the original hand drawings done by George DeAngelis. The carb sits in the intake with a .010" gap all around to allow air to enter the intake with gas. This is what Henry Ford did 120 years ago so when I cut the numbers in half I thought it would work.

Henry Ford did have a counterweight on his Flywheel and I do have the details on it. I did not make one for the half scale but now I am going to.

I took the entire engine apart the other night and cleaned out the cylinder bores, cleaned the spark plugs, inspected the pistons and rings, checked the timing, and took care of air leaks. The engine has a ton of compression and again worked great with a squirt of starter fluid.

This weekend I will try to run it on a constant fuel drip.

 

[cfellows]

Chris, I don't see the attachment...

 

[vascon2196]

Chris, I don't see the attachment...

Here is a PDF of the carb.

Oops!

View attachment CARBURETOR.PDF

 

[vascon2196]

Attached is a sketch I made of the intake/carb.

If I soak a small piece of paper towel and stuff it into the intake (5/16" opening), the engine runs until all the gas has been sucked from the paper towel.

If I allow small drops of gas to fall directly into the intake the engine will not run.

If I squirt starter fluid into the intake the engine will run.

I'm wondering if I need to add a screen mesh to not only spread out/distribute the gas but also restrict it a little bit?

 

[johnmcc69]

Hi Chris,

It sounds like the fuel is not atomzing correctly & will only run on vapor as you've seen. Maybe a silly idea, but it seems like the carb needs some sort of a "wick" in it, like a pipe cleaner or a very fine fuel filter material to prevent liquid fuel from entering the intake.

I dunno, just a thought....

Great build though!! I'm sure you'll get it sorted out.

John

 

[vascon2196]

Thanks John...I was going to try a wick from those Tiki Torches from summertime.

I'm heating my shop up now and hope to get this thing running today.

 

[vascon2196]

Still not running...now even with starter fluid it runs poorly. I need to take a break from this damn engine before it gets the best of me. I feel like scrapping the whole damn thing and starting from scratch.

 

[stevehuckss396]

Still not running...now even with starter fluid it runs poorly. I need to take a break from this damn engine before it gets the best of me. I feel like scrapping the whole damn thing and starting from scratch.

Way too close for that!

How about putting it away for a week or 2 and then trying again. Sometimes a break can help clear the head and give you a fresh look at things.

 

[Barnbikes]

On my dads Ford Pipe fitting engine it would not run with out the micro mesh screen.

Does the drip oilier screw directly into the pipe T? If so you are sucking gas only and no air.

 

[radial1951]

Still not running...now even with starter fluid it runs poorly. I need to take a break from this damn engine before it gets the best of me. I feel like scrapping the whole damn thing and starting from scratch.

Hi Chris,

Stay calm and don't throw anything, you might miss the engine and hit something important!

I have photos and video clips of quite a few Quad replicas and every one of them has what looks like various types of carburettors, no doubt because the one made by H.Ford and drawn by George DeAngelis was probably a touchy gadget.

Have a look here http://www.quadricycle1896.com/en/Videos.html at the Spanish replica Quad site. The second video clearly shows their caby at 3:45. The lever operated by the driver's linkage is on a vertical shaft with an arm underneath. That arm must have a pin going up into a slot in the moving spindle which goes through to the other side of the main air intake venturi to a fuel flow needle.

You can clearly see the upper operating arm moves the lower arm and that in turn moves the fuel metering spindle in and out to adjust fuel flow. I had to watch it a few times to get the idea. We can't see in the venturi to know if the spindle also has a shaped relief machined on it to alter the air flow at the same time as the fuel flow is adjusted. It should have, to ensure correct fuel/air mixture across the rev range.

Not sure what Dave Dunlavy used, but he is certainly happy to share info. Check his site at http://quadricycle.info or email him [email protected]

I was quite serious when I suggested trying a weedeater type carby to get your engine going. A rough idea of the required air flow might help with the choice, but it probably won't matter much, or just stick an old one on and see what happens! See your local mower repair man, I bet he throws them out! Or study how a model aircraft glow plug type nitro carby actually works. They are quite clever these days, and give excellent idle and throttle response and are fully adjustable with both low speed and high speed needles. They are cheap and come in a huge range of sizes as spare parts for various engines, and don't need or want gravity feed either.

I reckon either type of carby could get your engine going with only a little fiddling. I personally think a Walbro type carby would be the best and easiest to adapt. Have a look here: http://www.mymowerparts.com/partslist/25880/26492.php from $30 up. I would still just try an old one to see if it will run. You can run a fuel to oil mix anywhere from 20:1 to 50:1 like most of the 2 strokes these days. Always use Tygon Fuel Tubing for petrol (gas), not silicon as needed for methanol (alcohol).

If the air-fuel ratio isn't around 15:1 no amount of spark or compression will make it run. Well, not very well, nor for very long.

Regards, RossG.
radial1951
_____________
Sorry, a long post...

Edit: I also like Steve's idea, a fresh look in a week might bring on a revelation!

 

[vascon2196]

Thanks guys...a good nights sleep helped. I will absolutely review all the suggestions before going back to the engine. I appreciate the positive support and feedback.

 

[cfellows]

Chris, I know it's important for some folks to stay faithful to original designs on these kinds of projects, but if it were me, I would consider switching to a more conventional carburetor design. You have a lot of work into this sweet looking engine. At this point, I would do what ever is necessary to make it a sweet runner as well.

Chuck

 

[vascon2196]

Thanks Chuck...and everyone. I quickly designed a carb in SolidWorks and built it this afternoon. I hooked it up to a crude vapor tank almost like yours Chuck. The engine started running longer than 5 seconds! I almost had the damn thing running long enough to record a video but it kept stalling.

After a short while I noticed that I was losing compression in one of the cylinders...I cannot figure it out.

Sooooooo...I've got the entire engine taken apart. I am going to begin making decisions on what to keep and what to remake.

The frustrating part is I won;t be able to mess with the engine for a couple of weeks. I guess that is just enough time to calm down. Today was the closest to getting it running and then another problem that I can't seem to solve (at the moment).

 

[vascon2196]

Here are a couple of videos of me testing the spark and compression. My left cylinder will no longer hold compression and I can't find where it is leaking from.

 

[cfellows]

I'm wondering if you don't have some metal particles stuck in the intake valve? I find that repairing or replacing a carburetor, no matter how carefully I try to clean it, frequently results in wayward particles of metal getting sucked into the intake valve causing it to stick open a tiny bit. Sometimes holding the exhaust valve open and blowing several short blasts of air through the carburetor intake will clear it. Also, rapping the intake valve stem with my finger will sometimes shake it loose.

Chuck

 

[vascon2196]

Thanks Chuck...Weird...it had compression in both cylinders a few weeks ago and then something happened. It may be small metal chips like you said...I'll try to clean out the intake valves with some compressed air.

 

[radial1951]

Thanks Chuck...Weird...it had compression in both cylinders a few weeks ago and then something happened. It may be small metal chips like you said...I'll try to clean out the intake valves with some compressed air.

Hi Chris

If everything is clean and it still looses compression inconsistently, then the problem could be a valve not seating correctly.

Any errors in the concentricity of the valve stem to the head of the valve, the fit of the valve stem in its guide, the concentricity of the valve seat in the cylinder head to the guide and the angles and width of the valve seating area can all be culprits affecting the sealing of valves.

A valve can momentarily get hung up if it is cocked over for some reason, especially atmospheric intake valves which have a very light spring unable to pull it on to its seat.

Regards, RossG.
radial1951
_____________