Question-Horn Compressor

Moderators: 330GT, abrent

Post Reply
User avatar
gsjohnson
Posts: 106
Joined: Wed May 07, 2008 11:27 am
Location: Woodland Hills, CA

Question-Horn Compressor

Post by gsjohnson »

My horns do not work, but I can hear the compressor umphing when power is given to it. Additionally oil is coming out of a hole on the side of the compressor just below the power wire when given power. Is that hole suppose to be plugged? If so, with what? I tried putting my figure over it and it didn't seem to make a difference. As usual, thanks in advance.
GS
1965 330 GT 2+2 Interim
S/N 6997
Michael Bayer
Posts: 699
Joined: Mon Nov 04, 2002 7:22 am

Post by Michael Bayer »

Since you owned the car did they work? One or both trumpets? Do you feel the air coming out of the outlet if you take the hose to the trumpets off and engage the compressor?
Michael J. Bayer
330GT s/n 9727
365GTC4 s/n 14943
Dino Spider s/n 1193
User avatar
tyang
Posts: 3929
Joined: Wed Nov 27, 2002 10:28 pm
Location: New York
Contact:

Post by tyang »

Hi GS,

Funny you should ask. I just worked on a horn compressor. I don't know if it has the same design as yours, but it might give you a clue as to what is wrong with yours:
http://www.tomyang.net/cars/ferrari825.htm

Good luck!

Tom
'63 330 America #5053
User avatar
gsjohnson
Posts: 106
Joined: Wed May 07, 2008 11:27 am
Location: Woodland Hills, CA

Post by gsjohnson »

The horns have never worked since I have owned the car, but the compressor makes noise as if it is trying to work. I put several drops of oil in the oiling hole and it began to drool out of a hole on the side of the compressor below the ground wire. Not the power wire as I had originally stated. I then put power to the compressor and oil shot all over the place from that same hole. I then removed the compressor as well as the plastic plumbing hose to the trumpets in the nose of the car. The hoses as well as the trumpets also had a small amount of oil in them. I am getting ready to take the compressor apart as Tom suggested, but I wanted to see if any of these issues sound familiar with you guys before I dive in.
GS
1965 330 GT 2+2 Interim
S/N 6997
User avatar
tyang
Posts: 3929
Joined: Wed Nov 27, 2002 10:28 pm
Location: New York
Contact:

Post by tyang »

Hi GS,

One of the holes is an air intake, and perhaps the oil is overflowing its capacity. Looking at the design of the Marchal horn compressor, the oil resevoir is a small cup at the air intake side. As air gets pulled in, some oil gets drawn into the compressor. Too much oil might cause the condition you're describing. I hope your horn motor is as simple in design as the one I just took apart.

Tom
'63 330 America #5053
User avatar
gsjohnson
Posts: 106
Joined: Wed May 07, 2008 11:27 am
Location: Woodland Hills, CA

Post by gsjohnson »

Also there appears to be an adjustment knob that doesn't have an effect on the operation. Any info on how that should be adjusted?

And to the other unanswered question...When I place my finger over the hole, it does seem like it is sucking my finger towards the hole as if it is an air intake as you described..
GS
1965 330 GT 2+2 Interim
S/N 6997
John Vardanian
Posts: 1824
Joined: Wed Sep 04, 2002 12:13 am
Location: San Francisco Area

Post by John Vardanian »

I have also learned from experience that over oiling can spit oil into the horns and drown the circular reeds.

john
PF Coupe
Chris Coios

Post by Chris Coios »

If it is a Fiamm Roadmaster compressor, simply take the three screws of the top out and lift off the top. You will see the vanes. Make sure they move freely in and out of the holder as their centifugal movement against the cylinder allows the capture and compression of the air. The oil - only drops required - helps lubricate the vanes. If the chamber is full of oil, someone got carried away and the vanes are trying to compress and blow the oil, not air. Easy to test the horns themselves - just briefly blow compressed air at very low pressue directly into the hose fitting at the base of the horn. If there is no noise, the trumpet may be screwed down too tight, sandwiching the copper diaphram inside to the base, keeping it from vibrating. You can adjust the trumpet; screw it in or out for sound and then set the locknut again.
User avatar
gsjohnson
Posts: 106
Joined: Wed May 07, 2008 11:27 am
Location: Woodland Hills, CA

Post by gsjohnson »

Thanks for the insight. And I was probably over generous with the oil.
GS
1965 330 GT 2+2 Interim
S/N 6997
John Vardanian
Posts: 1824
Joined: Wed Sep 04, 2002 12:13 am
Location: San Francisco Area

Post by John Vardanian »

One more thing I recall is the veins can fit into the slots upside down, just the same, and cause misoperation.

john
PF Coupe
kare
Posts: 547
Joined: Sun Sep 22, 2002 11:34 am
Location: Helsinki, Finland, Europe

Post by kare »

Check (outer) electric connections first. It takes an impressive amount of current to operate and a bad contact will make it go "umph". I was naiive enough to test mine with a battery charger and after taking the compressor apart found that there was nothing wrong. I then tested with a battery and it worked all right. Best wishes, Kare
250 GT 2+2 3197/GT
User avatar
gsjohnson
Posts: 106
Joined: Wed May 07, 2008 11:27 am
Location: Woodland Hills, CA

Post by gsjohnson »

Okay, I've got them working. I'm not sure what I did as I didn't really find anything definitive. I removed the brushes and cleaned the contacts and then removed the 2 acorn nuts at the bottom to access the armature which I cleaned with a scotch bright pad. They appeared black in color, like they were carboned up, so I cleaned them both the brushes and the armature as a precaution. By the way, what I thought were the adjustment scews are really the brush access holes for changing or cleaning the brushes. I reassembled the bottom half and then took the 3 screws off of the top and removed the top half. It appeared to be like rusty oil inside, but the veins slid and moved freely. I cleaned it all out and made sure the passage ways were clear, but again, I didn't really find anything definitve. What I did find was, that I believe that the lid and the raises for the passageways must be sealed for the air suction and the passageways to operate at full CFM. I believe that this was not the case with my unit, but it's difficult to tell once you remve the lid. I saw remnants of a sealer of some type in a hardened shilac residue form. I razor bladed the old remnants off and applied a very light film of gasket sealer to the housing side. I installed the cap with the 3 scews, waited for an hour for the gasket sealer to dry and the horns worked. Thanks to everyone who gave me advise.
GS
1965 330 GT 2+2 Interim
S/N 6997
User avatar
tyang
Posts: 3929
Joined: Wed Nov 27, 2002 10:28 pm
Location: New York
Contact:

Post by tyang »

Hi GS,

All your work was probably cumulative. A little bit more speed from the motor, and a little more efficiency from the pump, and soon you had a working horn.

Isn't it refreshing to be able to fix something in a world where things are designed to be thrown away?

Tom
'63 330 America #5053
Post Reply