O2 sensor mounting

[ke_70_blue]

Ok so I’ve had a look around the webs and couldn’t find anything so I thought I would ask here

I have the 16v smallport with an O2 sensor and I’ve placed into my 71 and when I did the conversion I bought a set of extractors (TRD copy I was told) with no o2 sensor bung/adaptor on them. So this is where the problem lies, I have nowhere to place the sensor!!

I have come up with two ways to tackle this, one being get a hold of one of the ae92 manifolds and chop around the adapter and then weld it onto my exhaust just below the join from the extractors or
make my own bung/adaptor from cutting a hole in the exhaust the welding something that resembles the original on.

So my question would be what people have done to solve this as I’m sure it has been an issue for other people also

Cheers for any help

[70XIN]

Hey,

Yes you're correct, this is a fairly common problem - most people get an exhaust shop to sort it out or just ditch the o2 sensor and lose some fuel economy haha.

On a friends' car, we just made a simple flange out of some steel bar, and drilled an appropriate hole in the exhaust (headers actually, but anywhere at the start of the exhaust is fine too) and welded it on. It was very simple, took half an hour.



This is how they've done it on a set of greddy headers. It looks like it has some ~15mm tube to extend the flange out a bit.

[Matt]

Or you could run it just before the cat. Usually heated ones go in there

[cae-086]

I had this problem when i did my smallport into 86 conversion. You can get the weld in bung from an exhaust shop and a new universal o2 sensor from Bursons/Repco. New sensor is about half the length of the original sensor, and it should come with a threaded end to screw into a threaded hole, and a two bolt flange to fit into original toyota style manifolds. I was told the sensor should be placed where the pipes all join into 1. The weld in bung is just a single threaded hole that you can weld in where it suits you. Hope this all helps.

[pauliee]

^ got a photo at all mate? ive got the same issue!

[cae-086]

Hope it makes sense. The sensor is only about 2 inces long, and it was about $90 from Bursons. You should be able to get the weld in bung from them as well I would think. I'm using standard smallport computer, so I used a single wire sensor.

[ke_70_blue]

Thanks for the responses, both ways seem the goods. I already have my own sensor though so ill probably go with that first idea, 7oxin do you remember what the thickness of the steel bar was.
But I was once told that the depth of which you place the sensor will give you different readings, I’m assuming this incorrect though after looking at those getreddy headers. Does anyone know about this? Maybe it is a problem on only certain cars or something :/

[70XIN]

5mm thick.

The depth of the o2 sensor will make the reading ever so slightly different. Also, the further away from engine, the leaner your o2 sensors will think the engine is running.

The advantage to mounting the o2 sensor at the collector/on the exhaust, is it will be taking the average reading of all four pipes as opposed to just the one. But basically, all these things matter very very little - i'd put it where it's most convenient / aesthetically pleasing.

[ke_70_blue]

Sweet thanks for that info, my extrators are the same ones pictured by cae-086 so me planning to weld it just after the join is not much further past the join itself
cheers for your help guys