Are there any problems with using a synthetic oil (Amzoil) in a B20 ('71 142)?

There are some wiring peculiarities in this '71 142 and I'm not certain if the problems are because of that or are caused by my fooling around or part failures.

The windsield washers work, but the wipers don't. I traded switches (from my 164) and the problem remains.

The horn doesn't work. The horn ring grounds properly and if I attach a wire from the battery to the horn and press the horn ring, the wire gets hot, but horn doesn't honk. I'm not certain yet which fuse protects the horn in this car. There's no power to fuse #5. Fuse #5 has nothing to do with the lighter as it should - that is hooked to # 3, I think. I'm tempted to run another wire to the horn. Do I need to use a relay?

Thanks for the help, as usual.

Jim Hampton

Someone answered about the oil.

Either the wiper motor brushes are finished or the negative ground strap is not making good contact. Make sure the motor is bolted down properly. Test for power using a light bulb with wires connected to it.

The OEM horn has no relay. Power goes from fuse 2 via the horn to the ring to the chassis. I guess the contacts inside the horn is welded shut (there should be 2 horns, most likely only 1 is broken, test by connecting only 1 at a time). See my other post about different horns. Suggest you also add a relay when you change the horn, but not absolutely required (coil goes to + power on horn and to ring, contacts go to - power on horn and chassis).

Fuse 5 is for the rear window demister and overdrive. Fuse 3 is for the heater according to my wiring diagram, but I think this should rather be called heater fan. The cigaret lighter is not fused, goes via the ignition switch to the battery.

Have fun...

I would take the horn out and try it NOT in the car and see if you can
get it to work. They are pretty prone to failure and if shorted they do
draw a lot of current. The points inside could be welded shut, since the
coil in there makes it an inductive load so it sparks when they break.
(Wonder if anyone ever put a capacitor in a horn...)
What year is yours? I have a diagram for a 72.
--
George Downs Bartlesville, Heart of the USA!

It's a '71. Any help will be appreciated.

Thanks,

Jim Hampton

You can get rid of the spike by connecting a diode in reverse across the horn. This will save your relay points. Especially if you upgrade to an air horn.

What points do you have with an air horn? Seems to me they operate with
a valve, not a switch. (At least the one I had back in the early 60s
did)
--
George Downs Bartlesville, Heart of the USA!

I'm talking about those really loud horns which has a 12V air pump and 2 or 3 trumpets connected with a hose. The expensive ones can also play a tune, very popular in the 80's. But if you change your factory horn (or rather tooter) to an air horn, the factory relay is not rated for the high start-up current and the contacts often gets welded closed. Especially when you give the horn button a quick blip and the horn keeps going while you are in rush-hour traffic and have to pop the hood to pull off the wire to the pump (don't ask how I know...). A reverse diode across the pump power terminals will conduct the back EMF when power is removed, so the relay contacts will not see this back EMF.

Back EMF is not always a bad thing. In fact, it is what makes you car ignition work. You have current flowing through the coil, and when the contact breaker opens the inductance of the coil tries to keep current flowing by increasing the voltage (back EMF), which results in a spark across the plug. There is also a small spark across the contact breaker, but it is rated to handle it. The horn relay in your car is rated the handle the back EMF from the factory horn, but not from an air horn.

The factory horn is an electromagnet with a hammer which hits a metal disk for the sound and opens a series switch, the hammer retracts and the switch closes again to again energize the electromagnet and the hammer hits the disk again, and so on. I have not opened one, but there should be a reverse diode across the electromagnet to protect the contacts inside the horn (this diode can not be fitted externally, must be internal). Perhaps the early ones did not have a diode or it was underrated and did not last long, which might be why the contacts would often fail. And by the way, there is a screw on the outside which you can adjust to change the resonant frequency of the disk which indirectly changed the loudness.

Have fun...

I was not considering an electric compressor. Most guys who are really
serious about air horns (truckers, military vehicles, etc) use a compressor
driven by a belt from the engine, usually the same one that supplies the air
brakes. If there is a horn button, it operates a solenoid valve which is
usually not too big a current draw.

When I was using an air horn I used propane to blow it and it worked GREAT
until the hose, too near the battery, got a hole in it. Propane was pretty
much a surplus product in those days.
--
George Downs Bartlesville, Heart of the USA!

I can't comment too much on the electrical issues but here's what I can think of.

Maybe your horn is broken internally and maybe shorting out? Try just directly wiring it to the battery to see if it'll honk?(or maybe someone will tell me that's a bad idea)

There is no problem running Amsoil in your car. I'd just hope that your seals are good and you aren't burning any noticeable amount of oil because it may get expensive. But then, using the Amsoil for a few oil changes might reduce oil consumption if there is any. Go for it.

The wipers don't work? Have they ever worked? Have you checked the wiring out? And sometimes the wiper motors fail, so that could be it as well.

Good luck!
--
Kyle - '68 142? - Oregon Volvo Tuners?