EGT gauge no more burnt pistons.

[BoLongo]

I have had more than my fair share of burnt two-stroke pistons in my lifetime. I have read about Exhaust Gas Temperature gauges, but I have never installed one. I have a Challenger 1800 with twin 787s. I am on my second piston seizer, so I have decided to install an EGT system on my boat. The EGT gauge will allow you to monitor the exhaust temperature and shut down the motor before excessive heat can cause damage.

When I looked at the price for two gauges and four sensors, the investment was way more than I was willing to spend. I have decided to install the gauge on the motor I am having problems with and add the EGT to the second motor at a later date.

On the 787 engine, it looks like the Rotax engineers set up locations on the exhaust manifold to add EGT sensors for each cylinder. I plan to drill and tap holes for the 1/8" NPT sensors one for each cylinder.



I purchased the Westach self-powered Dual EGT Gauge, which should fit in the blank gauge on the instrument panel. When I decide to add the EGT gauge to the second motor, I will relocate the gas gauge and place the 2nd Westach self-powered Dual EGT Gauge in its place. That way I can monitor the EGT along with the RPMs.



I will add more photos when I do the actual installation. (parts on order)

If anyone has installed an EGT gauge, can you please share your experience.

 

[Matt Braley]

I install them all the time. I like the old Racepak stuff but it's not available these days. Guys have been buying the KOSO and so far so good. http://www.ebay.com/itm/Koso-BA006B...ash=item2ef12f4e47:g:Z-wAAOSwXeJXdk1M&vxp=mtr

I'd like to see the system you have because I have not heard of that one. I do use that location for my probes but I cut the tabs off first, there is still plenty of meat.

 

[snikwad003]

Both them gauge set ups are slick. Bo you can swap your speedo for a info center and have your fuel gauge in the middle and speed compas air temp and all that stuff and have your egts on the side like you said. That is what i plan to do with vts gauges insted when I do my dual vts set up

 

[BoLongo]

Westach has a good reputation in the Snowmobile and Ultralight markets. I don’t believe the gauge is waterproof, so it would not be good for a jet ski.

Westach self-powered Dual EGT Gauge $140
2- EGT Sensors from China $30.00
So $170 per motor is very reasonable for a boat set-up.

Matt, your setup is waterproof so if it's going to be submerged that is the way to go.

Josh, I can already hear my wife saying “stop talking to that guy right now, he is going to cost us a lot of money.:facepalm:” I want to know more about your plans for a dual VTS set up for the Challenger.

 

[BoLongo]

I install them all the time. I like the old Racepak stuff but it's not available these days. Guys have been buying the KOSO and so far so good. http://www.ebay.com/itm/Koso-BA006B...ash=item2ef12f4e47:g:Z-wAAOSwXeJXdk1M&vxp=mtr

I'd like to see the system you have because I have not heard of that one. I do use that location for my probes but I cut the tabs off first, there is still plenty of meat.

Matt are you able to use the EGT gauge to dial in the jetting as well as fine tune the carbs throughout the RPM range?

 

[snikwad003]

[MENTION=57920]racerxxx[/MENTION] put vts on his hx and im gonna do that x2 with some sort of custom button setup using the vts button covers to make it look like it is ment to be there from the factory with vts gauges and all

 

[BoLongo]

Update first mistake.

I got the EGT Gauge in the mail. The quality looks good. The backend is closed, no openings for water to enter. Fits perfectly in the blank slot, you can buy a light kit it if you want the gauge lighted at night. Still waiting for the sensors it will be another week.



I am ready to put the engine back together, so I am going to drill and tap the holes for the sensors in the exhaust manifold and reassemble the engine. I will install the sensors when they arrive. I am not going to start the engine until I can see the internal temps.

Somewhere I got it in my mind that the sensor should be between 3.5” and 4” away from the outside edge of the piston to operator correctly. There is 2” on the jug, so I placed a mark 1.75 from the edge of the manifold.



I first drilled the pilot hole with 1/8” bit; next followed that hole with a ¼” bit. Drilled into the water jacket on the manifold.



I am filling that hole with JBweld. I’m confident the JBweld will hold because some of the JBweld will lock into the water jacket. I will let the JBweld set and start over tomorrow.

 

[Matt Braley]

No. That's scrap metal now. Those are everywhere used for 25ish in great condition. I would not trust your new engine to that JB weld.

 

[Ankeneyou]

Agree. What happens when the JB weld breaks apart and rattles down into the engine?

 

[BoLongo]

Matt, Thank You

I bought a used one on Ebay for $18.00

 

[Andy4k6]

Why are you fitting EGT sensors instead of an AFR senor, I would have thought knowing the AFR would be more beneficial as you can ensure the mixture is right and in turn that should keep the EGT in check?

Andy

 

[BoLongo]

Why are you fitting EGT sensors instead of an AFR sensor, I would have thought knowing the AFR would be more beneficial as you can ensure the mixture is right and in turn that should keep the EGT in check? Andy

Andy, I have restored a couple 60s trucks and added Air/Fuel Ratio gauges on both of them. I have never thought about using one on a two stroke; I never made the connection. I would never add an EGT to a carburated V8 because the water gauge is sufficient in determining the engine temperature. The EGT becomes the water temp guage on a two stroke.

I can see the benefits and cons of having an AFR gauge on a two stroke. The 787 does not give me any real control over the timing so I would be limited to just the carburetor adjustments. With the understanding, I have now; I would still choose the EGT over the AFR, but I can see the benefits of having an AFR in tuning the engine.

 

[Andy4k6]

Forgive me for going off topic further,

If the only adjustment is the carb then I would expect AFR to be the better option and maybe EGT if you also had timing adjustments available.

How will you use the EGT to help?

Only asking as you ate tempting me to measure mine too

Andy

 

[BoLongo]

If I can use a car as an example, the temperature gauge is a safety feature. You can shut off the engine if the temperature gets too high. The AFR is a tuning aid; it is used to help you get the most efficiency out of your engine.
I am first looking for the safety that the EGT provides. I would not trade the water temperature gauge in my car for an AFR gauge. They are two different tools.

 

[Andy4k6]

That's a very good point indeed, I didn't think of it that way.

Although I suppose in this case a coolant temp sensor wouldn't be any use either.

I guess both would be good but then we only have so much dashboard room..... then again who fancies doing away with all the gauges and replacing them with an 8" touch screen incorporating all the gauges we want or need and some custom software

 

[Mekanix]

That's a very good point indeed, I didn't think of it that way.

Although I suppose in this case a coolant temp sensor wouldn't be any use either.

I guess both would be good but then we only have so much dashboard room..... then again who fancies doing away with all the gauges and replacing them with an 8" touch screen incorporating all the gauges we want or need and some custom software

You must learn the ways of Arduino and Processing! lol that would be the way to go if you want a nice custom display with unlimited arrays of sensors.

 

[BoLongo]

That's a very good point indeed, I didn't think of it that way.

Although I suppose in this case a coolant temp sensor wouldn't be any use either.

I guess both would be good, but then we only have so much dashboard room..... then again who fancies doing away with all the gauges and replacing them with an 8" touch screen incorporating all the gauges we want or need and some custom software

The newer Seadoos, Yamahas, and Kawasakis are amazing; computer controlled engine management. Ride control and even brakes (sort of). I was reading about a jet ski control system that can be controlled by a smartphone.

I think most of us on this forum are
# 1 Not willing to spend between $20,000 and $60,000 for a toy.
# 2 We have tormented souls that love to take older toys and try and resurrect them and maybe even improve them along the way.

I love modern engine systems and digital information centers, but if something goes wrong. I am quickly frustrated. Toys are supposed to be fun! I like to keep it old school because I understand old school.

As far as the Coolant Temperature Sensor is concerned, I have seized three Rotax engines and not once did the Coolant Sensor shut down the engine.

 

[snikwad003]

Not cheap cause no probes but its bad ass. I might do this for the cool factor if the budget mysteriously opens up. http://www.ebay.com/itm/231238815654

 

[CaptM]

Interested in EGT setup also.. What would be the normal and high temps for 787?

 

[Ankeneyou]

Want to keep under 1100 degrees.

 

[BoLongo]

Latest Update:

I have decided to install the EGT gauges on both motors; I should have all the parts this weekend.
I did get the replacement exhaust manifold, and I used Matt's suggestion of cutting off the tabs and installing the probe in that location.
One manifold is drilled and tapped, I'm pulling the other manifold today.



Painted ready to install.

 

[BoLongo]

Latest Update: Waiting on an exhaust gasket for one engine and it will be ready to test on the Lake.

All the parts cost a little more than $300. I am using direct burial 18/8 wire to extend the wires from the sensors to the gauges.


I had to remove the fuel pump bracket because it interfered with the sensor coming out of the exhaust manifold. I cut out a piece of 3” x 1/8 steel stock to extend the rectifier bracket, and I mounted the fuel pump to the extension.


Instrument panel with both gauges installed.


I still have a couple of hours of engine break-in, but after that, I will begin re-jetting and tuning my carbs.

 

[Andy4k6]

Looking good, I will be interested to hear your results once it's up and running.

Andy

 

[snikwad003]

Looking good Bo, what are you re-jetting for? And is your wire gas resistant it will say it on the side of the wire

 

[BoLongo]

Josh,

Rotax Aviation makes some of the most fuel efficient two strokes in the world. Rotax Marine makes some of the most inefficient two strokes in the world. I think they are inefficient on purpose. Seadoo has richened the fuel mixture to reduced heat, which reduced the number of seizers; especially while under warranty. In fact, when they discovered a design flaw in the 787 engine which was causing the rear cylinder to seize they simply increased the rear carburetor jet size to add more fuel which resulted in the cylinder running cooler.

My quest is to see if I can make the engine run more efficient which will lead to a better running engine. You’ve heard the saying it was running better than ever right before it seized. Well, I don’t want to seize an engine, and that is why I have installed the CHT gauges. I’m going to lean out my engines very slowing and very carefully.

Why? Burn less gas and get better performance; at least that’s the plan.

Which gas resistant wire are you asking about?