Projects Air Compressor Making loud Knocking noise

I have the exact problem now, knocking goes away as soon as pressure builds up. Been doing it for several years. I figured I had a bearing going. Would a bad reed cause a knock and then go away once pressure goes up? Seems like it has to be in the pump but going to pull the belt anyway, cant see why an electric motor would cause a knock.

 

My 10-15 year old Speedaire was making a knocking noise, finally let go. Took it apart and it looked like a reed valve had let go, destroyed the head.

 

This whole thing really has me at a miss, I just don't see how reed valves can cause a very pronounced loud knocking noise. I would have bet you anything it was a rod noise.

Ric, when yours was knocking did it quiet down when pressure came up?

29Sportcoupe, what type of compressor do you have? Does the knocking noise sound like a lower end knock?

Mm

 

You must be related to my buddy. His compressor makes such a racket I hate to stay in the shop when it's running and he turns the radio up so he can hear it above the compressor then he sings along with the damned radio

 

I could handle the radio, you wouldn't want to hear me sing!

 

check your belt for wear & bald spots & burns..

 

either let it in or get a restraining order...

 

restraining order....

My compressor is a 220v. Hurricane is written on the tank. The things over 6 foot tall so I want to keep it going. And yes it has a loud knock until air pressure goes up which is pretty quick. I figured I had a rod bearing going allowing it to have slop but now?

 

Are all the little screws that hold the reed block to the casing still there? I had one rattle out on me and fall down in the cylinder. Everything still worked find just made a lot more noise.

 

I'll be watching this one. I have a very old Campbell Hausfeld that's been knocking like crazy for some time. Same symptoms - noise goes away once the pressure comes up, everything else is tight. I might have to check the valves from the suggestions so far. Keep 'em coming.

 

Actually mine has rivets, the reed valves are riveted to a aluminum plate between the head and block. Everything seems tight. I'm thinking of buying the gaskets and a new reed plate assembly and seeing what happens.

I'm going to check prices, anybody know of a good place to get compressor parts?

Thanks

Mm

 

http://www.e-compressor.com/ THERES A COUPLE MORE ALONG THIS SAME NAME JUST SLIGHTLY DIFFERENT Whoops sorry for the caps!

 

Just thought I would let everyone know that I decided to buy the reed valve assembly and the gaskets to put it back together. I'm trying the outfit "Master Tool Repair" for the parts.

I'll put this back together in a few days when I get the parts, and be back with the answer to, can the reed valves cause a knocking noise?

So, to the guys who have knocking compressors and the noise is much quieter after pressure builds up, I'll let you know if this fixes the problem or not.

In a few days.

 

Had the same problem with my old Devillbiss 2 stage, check valve where the air goes into the tank was worn out , sounded like a rod knockin.

 

You have approach it and ask "Who's there?" Then wait for the punch line.

 

I had one like this too. I put a wheel cylinder cup on the top of the piston to cushion the noise, it worked.

 

?? Was there ever such thing, as a "quiet" shop-size air compressor ?

4TTRUK

 

We put ours in it's own ventilated room......

4TTRUK

 

I've heard of people saying this is something that could cause a knocking problem, but looking at mine I just don't see how.

When I have it in my hand, I do the blow, suck on the valve thing, (I might have stepped in it with that one) ,and it seems to work as it should, no strange noises let alone a knocking noise.

What did your valve act like when you were checking it out????

Thanks

 

Every time I asked who's there, it just kept saying, Knock, knock, knock, knock

I started to get bored with that after awhile.

 

I have been working on compressors for 11 years and still cant figure out why the check valves knock either. Even ones that seemed totally fine when looking at them just changing them would be the ticket. It has to be in the spring I would guess, but the thing is if it has to much spring pressure it will blow the safety on the discharge line.

 

Let me draw on your experience for a moment. Why would a semi clogged restrictive air filter make so much difference on my air compressor. Rattles, knocks, and scarry noises. Once I removed the restriction to the intake all was smooth and quite.

I do have my intake piped thru an auto exhaust muffler that dropped the decibel level by nearly 60%.

5 HP, 3400 rpm 3 phase with 2 stage pump

 

I do know that everytime I have ever re piped an intake on a reciprocating pump I have had issues with noise due to the lack of "make up air" and up sizing the intake diameter one size every few feet seemed to do the trick. Im sure it has something to do with lack of pressure inside the valvetrain. Ha Ha wich could also be part of the OPs problem on his unit. You got me thinking on that one!!! I will have to go back and read through his responses again was that covered already?

 

I haven't changed anything on the intake, its got one of those foam type filters and that's it. Its always been fairly quiet so I didn't mess with that.

I ordered everything except that one way valve going into the top of the tank, sounds like I should get one of those coming as well.