Acorn Presser Idea

[Christ]

As long as you only plan on running it at 1000RPM, you can probably use just about any spring that's just heavy enough that you'd have to apply pressure with your thumb to open the valve, honestly.

Just get the exact dimensions of spring you'll need and look for the weakest one you can find lol.

You should keep a running tally of what you've spent on individual parts for this in case anyone else is interested in doing the same thing or something similar. I was thinking about making a high volume compressor out of one of the 300-six engines we have laying around. Oughta be good for running anything I've got around here.

[zoom zoom]

I haven't been keeping track, but it's roughly $100 worth of materials so far, not including the 3/8" steel I used to mount the engine, the belt, the engine itself, the motor, the tank, the welding wire, the .... just in fittings and this spring I just got. I popped the intake springs off, and stuck a weaker spring in it's place...went to start it and the belt is slipping pretty bad and I've maxed out the slotted holes I slotted the other day.....my wife left about 10 minutes ago and my drill is still in the car with her from going to see Karl yesterday. If it's not one thing it IS another.

[Christ]

haha yea it is.. always something.
For what it's worth, you /may/ need a 2-belt pulley to drive that thing. The startup is what's gona be the problem.

You might also try using a combination of cog pulleys that will get you the ratio you need...

[zoom zoom]

It's got a two belt pulley on the motor, and I was thinking about welding a water pump pulley to the outside of the crank pulley but as it turns out, the water pump pulley is like a MM smaller than the crank pulley, so it wouldn't be exactly the same...might work anyway I don't know, I'll probably wait till I can get ahold of another v rib crank pulley or something.

[zoom zoom]

I had to cut the springs down a little, it's working like I had thought tho, only letting air in on the downstroke. I'm having trouble keeping the belt tight, the motor pulley spins fast and the belt is slipping in it. I either need a bigger pulley and a new belt for the new length, or to go ahead and set up some type of dual belt pulley system. I don't know if I should wait till the junk yard opens monday and try to retreive the pulley from that motor, or if I should go ahead with the water pump pulley and angle the motor shaft so it takes out the slack.

The whole 2 minutes or less that the compressor did work right, it built up to 30 psi in that 60-85 gallon tank, I've reamed out the mount holes further and the belt keeps getting slack in it so I kinda don't know where to go from here, probably gonna sleep on it and wait...just hope from here it doesn't turn into one of those projects in the corner that never gets finished.

[Christ]

I think I'd try out a cog belt pulley personally, bolt an idler tensioner somewhere on the side of the motor and use the crank timing pulley, find something to fit on the motor that'll give you the 3:1 or so that you need.

IT worked! Now just gotta get the kinks out.

[zoom zoom]

The motor shaft is 1" so I suppose ill have to find something to work with that.. I need tires so this is gonna have to wait till I can finish it for cheap.


Pics of the springs, it took a couple tries.with the height, a weaker and wider spring would be more ideal but this was what I came up with at the auto parts store for 2.99+tax.


Oh I dropped a keeper down one of the oil return holes and heard it ting in the bottom of the oil pan so it was a good thing I have a whole spare head to pull parts from..

[zoom zoom]

Alright...well I've decided that the motor just doesn't have the power to make the compressor turn over like it should. I put a torque wrench on the engine and it takes right about 10ft lbs to roll the engine over, any less and the tq wrench just clicks. Theres no telling how much torque the motor puts out but when the belt Jang slipping the motor never gets out of the start phase, it constantly makes the startup noise/whine.

So.. if I put a bigger pulley on the motor shaft, which is a 1" shaft, the compressor will spin faster, the startup torque will be increased, but will the torque needed to run the compressor be reduced? I was also thinking I've got an old flywheel and clutch I could probably bolt to the side if the extra weight would help?

[zoom zoom]

/e went out knocked the ring gear off the flywheel, bolted on the flywheel and clutch/pressure plate, it did help to smooth out the noise, but the belt still slips, and the motor still constantly makes the bad noise. Time for plan F.N.A.1/2.

[Christ]

Even at ~3:1 the motor won't turn the B3 over?

Changing pulley sizes won't make it so that it takes any less torque to turn the motor... it'll exchange torque for distance [that's what ratios do] so that the motor spins further, developing more horsepower [torque over time] per revolution of the driven item. The result, of course, is that the driven item is driven slower than the drive speed of the motor.

You shouldn't need the clutch/pressure plate on there, the flywheel is the balanced portion.

I think the problem you're having is the bending of the belts... also if the motor requires a capacitor to start, it may require a bigger one for the load it's seeing on startup.

To fix the belt bending issue, you may consider using the flywheel as a V-belt pulley and putting a bigger pulley on the e-motor. Larger belt = more belt surface engagement = less torque applied per square inch = less slippage and less belt noise.

[lessersivad]

If you had a serpentine pulley from an Aspire I would think that would do the trick.

Providing you could get a serpentine pulley for the motor.

I've had 3 different pieces (pulleys) machined for my generator projects. One is a 12kw and the other 15kw.

Both are running a simple 6 rib automotive serpentine belt with no slipping.

I do have an advantage of having a machinist as a neighbor though.....

[zoom zoom]

If I put a bigger pulley on the motor the compressor will spin faster, I don't know that it will help anything but I'm gonna spend another $20 on this for a new pulley before I give it up for a week. Hopefully TSC has a 1" ID/bore v belt pulley laying around tomorrow...in 5.5-6"

[zoom zoom]

Checked at TSC, they didn't have my pulley, manager wasn't around and I didn't want to wait...I picked up the in tank check valve and mounted it in the T fitting I had installed. Since it has the allen head set screw in the side I pulled it out and tested the unit, it spins fine when there's no pressure ahead of it, but if I leave the allen head in and try to pump up the tank the belt starts slipping.

http://www.youtube.com/watch?v=9HmPK1fFX1s&feature=youtu.be

[Christ]

Motor pulley is way too small... the belt has to bend around it too far, and that takes power away. You're also distributing the entire load of the B3 spinning across a very short surface. I'd suggest that even if you have a tensioner giving you 75% belt engagement on the e-motor pulley, it'll still slip as soon as you start building pressure.

I'd suggest a 1:1 ratio and a speed controller for the motor, but you'll lose a bit of efficiency on that... else, a much bigger pulley on the B3 and a fairly large pulley on the drive motor. Remember, you're trying to move a lot more air than a standard single or two stage compressor... that creates a lot more load, too.

Did you happen to get the 'pop' spec for your check valves? If you can, I'd start checking what sort of pressure you're getting in the cylinder before those 1/4'' nipples... seems like you're building up too much air resistance.

Fluid dynamics suggests that you're only able to actually use about 80% the volume of a rough ID cylinder for reasonably measurable flow, possibly less depending on condition of the tube. Even a micro-polished tube will only see about 98-99% pass efficiency per volume.

What you're doing is squeezing 325cc of volume [assuming 100% VE, which is not the case] through a tube 3'' long and with an area of .72-.104, that you can only successfully use 80% of, and less actually because of the speed at which the fluid must flow [creates more turbulence, thicker boundary layer], so we'll go with a 60% figure... You're now trying to pump 325cc through an area of .0832'' (assuming Sch40 and 80% volume). If you really want to find out why it's not working like that, remember to calculate the piston speed at your set RPM.

This is why I was saying earlier that 1/4'' was a long shot. 1/2'' is really going to be necessary and larger is quite possibly necessary.

[zoom zoom]

The 1/4" check valves open at 3 psi, and are rated for 250, the in tank check valve opens at 1 psi and is rated for 500. I could have gotten a couple 1/4" check valves that open at 1 and rate for 500, but they were $13 each instead of 8/ lol...

how about we try a bigger motor pulley, then I'll see about taking the head off and drilling/tapping for a 1/2" npt. It won't take more than $50 worth of pipe fittings to convert it all to 1/2". Those check valves were the same price or cheaper haha, nobody uses 1/4" or 3/8 but me!



thanks for the input so far man, like most of my projects I try to skimp on I'm probably gonna end up regretting not doing plan A as mentioned in the beginning of the thread heh...