AF meter

[Bill S]

How do you install a AF meter? What parts are needed?

[51 MERC-CT]

The meter is the simple part. You have to drill a hole in the exhaust pipe and weld on a bung to accept the sensor. All parts and instructions should come with the kit.
Also should be 12 volt system.

[TStiles]

Bill,
I've been wondering exactly the same thing. Is there someone who can explain the parts needed and installation in a little detail?

[Pete]

Here's a couple kits. Instructions are included. Easy to install.

http://www.jegs.com/i/Innovate-Motor...oductId=857489

http://www.autozone.com/autozone/acc...er=976797_0_0_

Basically they use a wide band oxygen sensor from a modern car with a calibrated meter.

[Henry/Kokomo]

I just put new headers (Reds) and head pippes on my '46. I put a sleeve in the passenger's side head pipe to have a place to hook up an AF meter in the (hopefully) near future. I purchaced an oxygen sensor sleeve from Speedway and a matching plug. I welded the sleeve into the new head pipe after finding a relatively easy-to-access spot. I then made a copper gasket for the plug, coated the plug's threads with Nevr-Seez and installed the plug.

If I've done the job right, I should be able to remove the plug, thread in the A/F meter probe into the exhaust pipe and connect the probe to the meter which will be in the car's interior. I'm sure it will require a source of 12V power and will have to be grounded / earthed but, with the meter in the car, that shouldn't be all that difficult.

Yet to be determined if this will work as planned. I'd contemplated putting one probe in each head pipe but was subsequently convinced that would have been overkill. I'll let you know how it works sometime this summer.

[Ol' Ron]

Sponsored Links (Register now to hide all advertisements)

Th wide band sensors we use are quit expensive upto 300 bucks plus. However Cyberdyne makes a unit that does not read in fuel ratio numbers, but in graphic form with red yellow and green leds. This unit can be operated with a junk yard sensor which must be placed in the exhaust. I used one of thes for years when tuning for powere on the dyno and it worked quite well, definitely improving performance. what surprised me was how bad the engines were tuned, but still ran good, most were rich. At present our engines are running in the hi 15:1 range with no ping or over heating.

[Richard in Florida]

Originally Posted by 51 MERC-CT

You have to drill a hole in the exhaust pipe and weld on a bung to accept the sensor.

It's important that the hole you drill is not below 3 o'clock or 9 o'clock (if you were looking straight through the pipe). Otherwise, moisture and all sorts of bad stuff will collect on your sensor when the engine cools down and shorten the sensor's life.

[JohnL]

While it's right that a junkyard sensor is better to tune with than just guesstimating the AFR, these narrow band sensors are really only rich/lean toggle switches, that is, they have no sensitivity very far away from 14.6 or 14.7 to 1.



Another thing to keep in mind when mounting a wide band sensor is that condensation can kill them, so they need to be mounted away from the bottom of the exhaust pipe- maybe from 10 o'clock to 2 o'clock.

[Ol' Ron]

This is very true, however they do tell you where the sweet spot is and they are very inexpensive.

[Tom Walker]

I've used the narrow band sensor and colored light read out for years and find it very useful. The great thing about them is that you get the reading in "real time" ie driving down the road, and you can check the fuelling at various throttle settings and loads.

You need to weld the threaded bung into the exhaust system just after all headers join together. If you mount the sniffer towards the back it wont work because it needs to be hot.

In my 6v Hup (havnt got one in the Tudor yet!), I just carried a 12v battery on the floor passenger side to power it.

Tom.