Widebands and sensor location
 

Well after the advise of others from my previous thread here:
https://www.offshoreonly.com/forums/...ker-build.html

I am looking into Wideband kits but the main question I have is where is the best spot to put the O2 sensor in My Stainless Marine risers? Plus if located in the riser then I have the other issue of the double walled riser. Getting a bung welded in properly through the water jacket seems tricky. Also, the water mixes with the exhaust at the very end of the riser. Can the O2 sensor be located in the aluminum exhaust manifold or is that too close to the head? Be simple to drill and tap a hole in the manifold. See attached images of risers.
https://cimg0.ibsrv.net/gimg/www.off...e4903da2fe.jpg
https://cimg1.ibsrv.net/gimg/www.off...dad2494507.jpg


Also, any suggestions on a simple kit with a gauge? Would like to put a gauge on the dash.

Any thoughts and recommendations is appreciated.

Thanks again,
Jim

I would pull a riser and put it as close to the exit of the manifold as possible. I can take a picture of what I did to one of my stock Mercuiser risers to get an 02 sensor in it.

Basically drill cut a hole in the outer pipe, 2 ".
Drill and tap the inner pipe to except the sensor, which you may need a bung so that you have more threads.
In that case weld the bung to the inner pipe.
Find a piece of stainless pipe about 2" and cut it to fit so that it slides in the hole and makes contact with the inside pipe, and has enough sticking out of the outside pipe to weld around.
Weld around the inside and outside of the pipe.
Now you have sealed the water off around the sensor.

I will snap a picture of mine tonight.

Makes sense, I was thinking that would be the only way to do it, and getting access to that inner pipe.


The procedure in that link would be a little easier as long as the clearance between the inner and outer pipe is small enough to allow the inner pipe to dimple in. Great info and images.

I have a feeling I wil be doing it the way "Paxtonspeed" did as I think there might be about 3/8"-1/2" between the walls. I will have to drill an 1/8" hole to find out before I figure out which hole saw to start out with.

See the photoshopped image below, are these locations for the O2 sensor adequate? A or B or....

https://cimg9.ibsrv.net/gimg/www.off...cf0ab389be.jpg

Thanks agian

I would put it here. The further you can get it, from where the water mixes the better.https://cimg6.ibsrv.net/gimg/www.off...e388fae9d1.jpg

The Hardin Marine LS engine manifolds are where I got the idea for mine. I pretty much did the same thing in this picture to one of the 3 inch spacers that go under my risers.https://cimg7.ibsrv.net/gimg/www.off...2b9968f021.jpg

Mine are just above the hose

https://cimg2.ibsrv.net/gimg/www.off...4fb1def811.jpg

How's this location? Would like to keep it "out of the way" so as not to bump or snag it while working on the engine or standing in the engine compartment.
https://cimg5.ibsrv.net/gimg/www.off...dc2e582504.jpg



Also, do I need a sensor for each riser or is one side of the engine ok? Innovate makes a 2-wideband gauge. Link below
https://www.innovatemotorsports.com/products/dlg1.php

where did you get those uprights? or did you modify the ones you had?

A simple kit is the AEM 30-4110. Here's the cheapest place I found selling it. AEM 30-4110 Wideband UEGO kit - Great for Monitroing Air-Fuel Ratios - new LSU4.9 sensor Before ya go drilling holes you should get the kit and read the instructions. My kit said sensor needs to be at least 18" from the exhaust port. I installed mine in my double wall tails like Eddie Young showed doing it in the link. It's incredibly simple doing it that way. Here's some wideband compare info.....https://10carbest.com/best-wideband-gauges

Put bungs in both exhaust. You can run the double kit or 2 of the single kits are cheaper. Or just a single and switch back and forth and compare.

https://cimg3.ibsrv.net/gimg/www.off...112f93447f.jpg
This is where you want them, easy to weld in also, you can get to the inside and outside of pipe, no hackwork..

more than likely neither of these will work, there will be enough revision way up from there to kill them quick, tried many places and killed several $150 sensors. only place we got to work was in a header tube about 6" from head and worked fine. I know we were using lightnings on a HP500, but you will be shocked how far water mist is drawn back into exhaust

Many have used the Innovate 'heat sink' with success with engines/exhausts with reversion issues..if I remember correctly...no ?
https://cimg1.ibsrv.net/gimg/www.off...0063a47828.jpghttps://cimg1.ibsrv.net/gimg/www.off...ba4a818e0f.jpg

Here is what I came up with.


https://cimg2.ibsrv.net/gimg/www.off...f11d126599.jpg
https://cimg1.ibsrv.net/gimg/www.off...2112852e1a.jpg
https://cimg3.ibsrv.net/gimg/www.off...f30ed46006.jpg

That's the same unit I've been using, I've used it as just a reader and data log. I'm not arguing with the instruction but I've measured just after the collector mid way down the pipe and as close to the end of the pipe as possible with only .1 difference in AR ratio readings.

Ive had good luck with these (link below) for preventing water on the sensor. It does delay the response time.....so I wouldnt use it for accelerator pump tuning or other quick transients....but for steady state stuff it works well.

That would be perfect if the bung could be welded from both sides, pretty tight access to the inside though, but looks like it could be done (obviously yours worked well) with a torch with a short back cap and maybe a swivel torch. Going to see what my welder thinks about the access.

Read some reviews about these and people seem to like em.

Thanks, I think I will do both

They are a great addition if you run to guages at dash.. but make sure that they can be seen as the gauges don't seem to have the same characteristics as Livorsi/Gaffrig gauges. Sun hits mine at any angle and cant see.. mind you mine are digital display. maybe my mistake

I use this. I've done before and after testing with this on the same motor, same day, same tune. No difference in AFR readings or response time. Provides a little extra protection should any reverted water drip downward from the elbow towards the wide-band sensor. It is meant as an extreme heat shield for turbo motors but also works in defending against reversion.

For those drilling in and welding in bungs at the bottom of a standard Merc style elbow you can get a Wags engineering spacer or one for LA Boat Parts that is much simpler.

we also tried these, and even extended one further and still killed it..

also tried these, and actually added length to this...not sure how great of a reading would have gotten but killed one pretty quick...spent $$$$$ on sensors...maybe my lightnings were just bad for it ?

Thank you so much for posting this. I have been looking for a spacer for a while for stock style 496 exhaust with no luck! Just sent Wags an email.

Good luck with that. I've emailed and called them with never a response.

Ironically I have mine installed on lightings as well.....so far so good........but I only have about 20 hrs on them....it was more than enough to get my carbs dialed in without killing a sensor.

maybe I have less water or less reversion ..... who knows......the bung is on top of the collector as close to the primaries as I could get it.....I never tried a sensor without the 90* fitting I linked.

Did the one you tried have the reduced inner diameter/orrifice before the gas enters the "chamber"?

Well I finished the bung mod. I thought I'd share some images of the process, which could help others down the line.

I did a similar technique as was suggested here.
https://www.offshoreonly.com/forums/...sor-bungs.html

I first marked where the sensors would sit so they would clear the valve covers, then drilled an 1 1/4" hole through the outer pipe, then a 3/4" hole through the inner pipe. I drilled two different holes to allow easier welding of the two walls. And the holes drill like butter with standard bi-metal hole saws, cutting fluid, low rpm drill press and lots of pressure. Each hole took about 15 sec.

Next step was to "dimple" the outer pipe. There was about a 1/4"+ between the outer and inner pipe so I had a ways to bend the outer pipe in. Given the size of the 1 1/4" hole, I used a 2" trailer ball and my hydraulic press, much easier then trying to beat it in with a sledge.

Once both risers were "dimpled" I took them to a welder friend which took him 15 min to weld the inner and outer pipes. Then took them home and pressure tested, all good. But I had to get creative to seal off the inner and outer pipes, but it worked.

Next I prepped the bungs. I decided to use the Innovate heat sinks, so I installed the heat sinks in the bungs, tight, and then placed them on each riser so the heat sink holes were facing the right direction (into the exhaust flow). Marked the placement of each one and then beveled the bungs accordingly to fit over the welds so the bungs sits square and also so the heat sink hole protrudes far enough into the exhaust.

Then took the the risers and bungs back to the welder and 20 min later voila!

See images below of the process. Hope this helps someone like the advise I was given by other posts/posters help me, and gave me direction.

Jimhttps://cimg9.ibsrv.net/gimg/www.off...87386965f6.jpg
https://cimg0.ibsrv.net/gimg/www.off...3083ca5162.jpg
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https://cimg9.ibsrv.net/gimg/www.off...bed501810f.jpg
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Looks great!

Worked out nice!