PICS...Adding Oil Temp Gauge...A Few Questions
 

I am adding an oil temperature gauge from the Livorsi Redline Series. I like the idea of a warning light integrated into the gauge. Picture is of oil pressure gauge, but you get the idea.

http://www.livorsi.com/catalog/redline.htm

This is my current dash configuration is pictured below.

The possibilities are:

1. Replace the depth finder, which is never used

2. Relocated the 12V receptacle that is to the right of the wheel

3. Redo the dash panel; rearranging the gauges to squeeze the oil temp gauge in.

Where should the temp sender be located? I have read that it should be tapped into the oil pan...not fired up about having the motor pulled again. Where else can it be located?

What temperature alarm set point should I choose? 250 or 300 degrees? Running Castrol Syntec 10W-30.

The pans good but oil filter adapter works good too. My guess is if you run hard your at or above 250. I think 300 is the setting to use. I think you should conceder a heavier oil Merc Suggest 25-40. I like 15-50 Mobil one if you run hard. Opinions will vary, this is mine.
Jim

I believe the sender should be in the remote filter block as well. It's easy since there are usually 4 ports. 2 in 2 out. Put it in the other out port.
There are alot of guys who will say put it in the pan. But why have a huge concern of what the temp in the pan is? You want to know the temp of the oil that's going to hit the bearing. Oil tempature to the bearing is the most important for viscocity reasons first and formost.
Furthermore, you go through a cooler before the bearing. So how do you know if you're over cooling or under cooling?

DAVE

Measure the oil temp in the pan. What is the point of measuring the oil after it has been cooled?. If your engine is failing or having a serious problem, you will see a spike in the oil temps in the pan, after it's been cooled, it isn't so obvious. If you are concerned about oil viscosity breakdown, you want to know how hot the oil has been before it was cooled. If the oil is breaking down at temps over 300, how will you know it has exceed 300 degrees if you measure the temp after it has been cooled?

I agree it makes no sense to read after the oil is cooled, i due both one in the pan on a gauge and a warning light on the dash plumbed into the oil filter adapter......I would use a 270 waring light........You should notice the jump in pan temp way before the light goes off.........




It is hard to see in this pic but the oil pressuer gauge is on the left ond oil temp on the right both have warning lights....

Why does it not make sense to you to measure oil temp to the bearing? The oil is not doing much of any job in the pan. It's getting reading to do it's job going to the bearing.
Your oil doesn't go "SNAP" and turn into wax at 300 degrees.

You will still know when there is something wrong with your motor no matter where the sender. But if the sender is telling you what's going to the bearing you'll know when you no longer have protection.
Just because your oil is 300 degrees in the pan doesn't mean you don't have protection as long as the cooler is able to get it to under 270 or better.
Now we all know you don't want it that hot but I'm just making the point.
The other side to that coin is, what if your oil is say; 140 in the pan it goes through the cooler and hits the bearing at 100? How much protection are you getting there? Enough, probably but, would you run WOT with those temps?

It's perfectly fine to measure oil temp in pan, if that's what you want to do. But, it's not telling you as much as you think it is.

Look I'm not just making this up. I've worked around huge compressors and steam turbines for 20yrs. The resevoir has a local temp, oil is pumped through a cooler and on the outlet of the cooler is the thermocouple which sends to the computer for the operator to monitor. The operator will adjust water to the cooler to adjust temp.
I've discussed this with rotating engineers because this subject has come up so many times on this board over the past 10 yrs.

If you disagree, that's surely ok. I'm always up for a friendly debate.

mine is mounted in the remote oil filter hosuing. which is before the cooler. I want to know how hot the oil is coming out of the pump at. This is almost the same as measuring at the pan. The pump adds some heat, but I know what my MAX oil temp is. If I measure after the cooler, I don't really know what the engine is seeing or doing. I just know its at "X" temp going into the motor. If yo had a monstor cooler, it could drop your temps to say 250, when the motor is seeing 300+ which you will never know if the gauge is mounted after the cooler.

I'd also set your alarm at 250*. 300 is "ok" with full syn, but you don't want to be there. I've run up to 260, before I put my larger cooler on. Now it stays at 230-240 no matter how long I run it at WOT. I'd rather have the alarm going off at 250*, then all of a sudden having it going off at 300 if I haven't been watching it.

Plus, I agree with the others about changing the oil weight. I run Amsoil series 2000 20-50. for the load we run, I think 10-30 is too thin.

Measuring in the pan is showing you what temp the oil is at after it did its job. Thats what we want to know, how much heat it took away from the bearings etc. If you measure it before it does its job, you have no idea what temps ats at when its actually doing its job.

Exactly!!!! I keep trying to tell people that you want to identify a problem as soon as it happens! If you are running lean and starting to melt a piston, you will see higher temps in the pan, but not after the oil has been cooled. Compressors are a different animal. They do NOT have to deal with the heat or contamination of combustion. The heat that is generated in a compressor is from friction and the heat from the compressed air soaking into the metal. Compressors (piston type) either are running or not running. Compressing air, or "freewheeling", where the compressor turns, but the intake valves are held open. Their load is easily factored as a "duty cycle". Boat motors don't have a set "duty cycle". That is why it is more important to know what is happening with the oil as soon as possible. Oil doesn't go "snap" and turn into wax at 300 degrees, but even when it is cooled down to a lower temperature, the damage to the oil viscosity has already occurred. If you always measure the oil after it has been cooled, how do you know if the oil has ever been overheated and suffered breakdown? Engine fluids should always be measured at their extremes. Would you want to know the temperature of your coolant is after it has already gone through the radiator on your car?. Of course not. The sending unit for the coolant on your car is where it is the hottest, just before it goes into the radiator. Oil temps on cars are measured in the pan, not after it has gone through a cooler. Why don't people question where these are measured? Automotive engineers generally measure fluid pressures and temperatures at their extremes. Where the fluids are their hottest and the pressures are their lowest. And yet some people think boat motors are sooooo different.

The reason you don't measure water temp after the radiator is because the job of the water is being done in the motor. The control valve is the T-stat. That example is totally different. Also with a T-stat in, that's where water press will be high. Low press will be on the downstream side of the t-stat.

I agree that you both make a good point about oil in the pan after it's done it's job. But, the temp of your oil is linear at a given rpm...unless you have an oil T-stat. The only way to know exactly what's going on is if you had a TI at the outlet flow of each bearing. Then you both would be totally correct.
If your oil is overheating in the pan you will still have hi temps after the cooler. Duke has a slightly different plumb.

It only takes a few seconds to put a hole in a piston. I just don't think that oil temp in the pan is going to tell you all that much that fast.

Use two senders and a switch and measure them both. I'm a pan man myself. I'd rather know before temps than after.

You guys are all right but think of application. Custom pans blown motors yea play it all the way, stock motor be realistic is it worth tapping pan mid season? Does someone make a sender that goes in drain plug threads?

THat should be easy enough to do.

For location, why not get a pod and put it next to the compass?

http://www.livorsi.com/catalog/acces...s_brackets.htm

I think the pod would look like an after thought.

I am probably going to move the volt meter down to the right of the steering wheel where the DC accessory plug is now. I will probably put it in an angled bezel from Eddie Marine and tilt it up.

http://www.eddiemarine.com/store/car...l&p=12587&c=25

I would relocate the DC accessory plug into the glovebox for use with the iPod and inflator.

I'd like to see what the differential would be ... I have a manifold tapped off the remote .. pressure,temp and alarm ...comes straight from the block ... at 5000 rpm how long does it take the oil to get from the pan to the remote? I would guess the mass from the motor and oil in the pan give a better reading but how much could the oil cool in that short distance?...

Here's another vote for measuring at the hottest point.
If you accept that the engine adds X amount of heat TO the oil, and the oil cooler draws Y amount of heat FROM the oil, knowing the max temp allows you to work backwards to regulate that max temp.
So what is the oil flow in a stock Merc setup? oil pump, filter, cooler, engine? Or does the cooler come before the filter?

I agree. Find where the oil is the hottest and cool down from there. I"m not sure how mercury has their engines plumbed. I prefer to filter first, ( while the oil is the thinnest ) and then cool. Oil filters cannot filter all the oil at high flow, especially when cold. That is why bypasses are built into oiling systems. Some people argue that you should filter before the cooler, some people argue after the cooler. Oil will pass through a filter matrix faster when it is hot and thin than thick and cool.

At Stef's we recommned pulling temp from the pan. In speaking with a few oil guys they also say the pan is the most ideal place to pull temp. . .you want to see what the oils temp is after it has done its job.

A temp sending unit to go in place of the plug is available as they are common on most dyno's.

Here is another combination. We put the oil temp sender in the oil filter/thermo housing after cooling. We then have a separate high oil temp sender in the pan connected to a dash warning light mounted next to oil temp gauge (top left).

nice lookin dash man.............

What size sender do I need on a 2000 7.4L MPI? 1/8", 1/4" or 3/8"?

I have decided to mount it at the filter bracket instead of at the pan. I can do it myself and I will not miss any time in the water. The mexhanics in this area usually run 7-10 days just to take a look at anything.

I have decided to move remove the depth finder and replace it with the oil temp gauge. I'll leave extra wire in case I want to shift things around at a latter date and add the depth finder back in.

One easy way to confirm the size is to pick up a pipe plug of each size at any hardware store...for maybe $2 you will know exactly what to order.