Couple air compressor questions (maybe trouble?)

[vintagefan]

I just picked up the last 60g Husky in my area, the red one they were clearancing.

http://www.homedepot.com/h_d1/N-5yc...0053&langId=-1&keyword=husky+60&storeId=10051


I got it home and installed it to the garage floor with large rubber sandwich mounts, so it is 100% isolated. You can't feel even the tiniest vibration in the concrete. I also installed a much nicer aftermarket pleated filter, and new regulator.

Anyways, when the compressor starts, the motor vibrates about 1/16" or so. As it starts to build pressure though, it gets really bad, like the back of the motor is moving almost 1/4" up and down

I'm really afraid that it's going to eventually crack the motor mounting bracket.

I can't imagine this is normal?? At least, I've never seen a motor move that much on a compressor, and I've been around them daily for 15 years.

Could it be one of the pulleys or even the belt?



Also, the crankcase is building pressure. Not a lot, but enough to hiss and build pressure behind the cap (I leave the cap cracked a bit so it can vent). I'm finding mixed opinions on google as to whether this is bad or normal.

Some say it is the rings, but I don't want to tear apart the head on a brand new compressor pump to find out when it might not even be an issue at all.



Thanks in advance

 

[fred d]

Home Depot has a very liberal return policy

Find another Home Depot with the same model, take that one back and get the new one

 

[vintagefan]

Unfortunately a return is not possible. There isn't another compressor within a 2 hour radius of me. This model has been clearancing for months, I just happened to get the very last display model in my entire metro area (4 different home depots)

 

[Davefr]

I don't see how the motor could move 1/4" up and down if it's bolted to the frame. It sounds like the motor mount is loose.

 

[Major Ramifications]

Something doesn't make sense. When you say that the motor is moving, do you mean that the whole compressor is moving on the isolators that you installed between the tank legs and floor? If so, they are WAY too soft.
You don't need to leave the oil fill cap "cracked", because it is vented.

 

[rlitman]

If the hiss is the sound you hear after the motor stops, that is the unloader. It is doing it's job by relieving the pressure in the lines between the pump and the tank inlet check valve when the pump stops.

Yes, a belt can induce vibration. You could get a link belt, or just not worry about it. If the motor is moving, it sounds like it isn't bolted to the frame firmly.

 

[Steevo]

If it has been a display model, the belt has probably taken a set from being in one position for so long.
Just replace it with a good quality Gates or Dayco belt and see if that cures the motor bounce.

 

[vintagefan]

I don't see how the motor could move 1/4" up and down if it's bolted to the frame. It sounds like the motor mount is loose.

About 2/3 of the motor's length hangs off the front, and is otherwise unsupported. The motor is held on by a sheetmetal bracket which is only about 1/4 the length of the motor, and has a good deal of flex.

Something doesn't make sense. When you say that the motor is moving, do you mean that the whole compressor is moving on the isolators that you installed between the tank legs and floor? If so, they are WAY too soft.
You don't need to leave the oil fill cap "cracked", because it is vented.

The isolators are properly sized, in fact I had one of the mechanical engineers here double check my selection just to be safe. They're working quite amazingly.

I don't have the vented cap, only the plastic plug that comes from the factory, so yes I do need to leave it cracked, at least until I have a proper breather installed that is.

If the hiss is the sound you hear after the motor stops, that is the unloader. It is doing it's job by relieving the pressure in the lines between the pump and the tank inlet check valve when the pump stops.

Yes, a belt can induce vibration. You could get a link belt, or just not worry about it. If the motor is moving, it sounds like it isn't bolted to the frame firmly.

It's not the unloader valve, it's the crankcase breather/oil fill port. I think a link belt is probably a good starting point.

As far as the motor's mounting, the bracket itself is cranked down hard, it's just not a very sturdy bracket.

If it has been a display model, the belt has probably taken a set from being in one position for so long.
Just replace it with a good quality Gates or Dayco belt and see if that cures the motor bounce.

This sounds like a very feasible solution. That compressor probably sat with no movement on the belt for literally years. I'll inspect the belt first, to see if that may have anything to do with it.




Thanks for the help so far everyone. I'll take a few different pictures and perhaps a video when I get home today.

 

[Davefr]

Those floor models are often not set up correctly, parts missing/swapped and possibly damaged.

I'd make sure all the fasteners are tight. Now make sure both pulleys are aligned with each other. Use a straightedge to check them. (if they're not in line that can cause some significant vibration). Now make sure the pulley set screws are tight.

Check the belt as Steevo recommended.