Oil temperature issue
 

I have a question about oil temps. What is ok and not ok. I am running Amsoil 20x50 oil Full Synthetic. At the beginning of the season I had thru transom with silent choice and my oil temps would be around 225 degrees @3400 rpms. Water pressure was 10-12 lbs . I also had custom tee fittings between the exhaust manifold and the riser dumping some water over board to help stop the reversion. I removed the silent choice due to reversion issues anyway. I sent out my short style Eddie Marine stainless steel exhaust risers and had them extended to standard length. I noticed when they came back the water outlet holes at the end of the exhaust pipe were small.3 of them. I called Eddie Marine about that and they said they made them smaller to hold back the water to help cool the SS pipes better.I have been noticing that my water pressure is now 14-16 lbs@3400 rpms and my oil temp is also running higher around 230-240 cruising @ 3400 rpms. I re hooked up the fittings to dump some water before the risers again like when i had the silent choice and the water pressure dropped 5lbs and the oil temp went down 10 degress, the only dilema is the SS pipes at idle were getting hot from the reduction of water. So with the water dumps installed I am getting lower water pressure and lower oil temperatures because the water is flowing thru the cooler faster but when i disconnect the water dumps and all water is coming out the 3 little holes at the end of the exhaust pipe the pressure and temp goes up BUT my SS pipes run cool at idle....SO...what do i do???

Any input would be appreciated.

Your oil temps are fine, I run 260+ at 4800 RPM for 5 miles or so, idle the last .5 mile to the boat house and temps drops to below 180.
I run a 100% petroleum oil, never worried.

Ken

240-250 on synthetic wouldn't bother me.

But, what would concern me is this - what happens when you run WFO for a while?

If it was the Temp in the oil pan I would say no problem but if it's after the cooler then you need to see what the pan temp is and go from there...

[ATTACH=CONFIG]544161[/ATTACH]The oil temp sensor is located on the remote oil filter. I believe that is before the cooler. Looking at the arrow on the remote oil filter housing, that oil line comes from the block, feeds the filter then heads toward the oil cooler then out of the cooler and back to the block. I am more concerned about the cruising 3400-3600 rpm oil temps more than WOT. I do more cruising than wot and if i run at wot its not for very long. After the last wot run I really didn't look at the temp, I was more concerned what was in front of me but i can say after stopping and idling for a few minutes the gauge was down around 200-210. No alarms or buzzers. I'll have to take note of the oil temps the next time i open her up.

I would want my filter AFTER the cooler to filter out anything that might be in the cooler. Filter as the last thing before it goes to the block has a good feel to me

Thats how I set mine up, I want it filtered right before entering block, some will say hotter oil filters better but I never had any issues..been that way for years...

How about a larger oil cooler. 240 degrees at constant cruise, is too hot in my opinion.

What temperature water thermostat are you using?

Uhh, if the filter is in front of cooler how did chit ever get there? I've got believe that hot oil is going to filter much better than cooled.

Just remember, oil is tested for viscosity at 210. That is under no load. 30 degrees hotter is nothing to worry about.

FWIW, my temp sender is located in the filter housing also.

Ken

It has been said several times before filter 1st(hotter oil filters better) then cooler...seems cruising temps a bit high to me...

I wasn't the guy who said that stuff gets there but cooler material and inner line material can all age, I prefer to have my filter be the last thing before entering block, again why not? Never had one issue and many run this way actually

My temp sensor is in the same place, cruising it's 170-180, hard I mean HARD WOT is never more then 230

I have the same risers, and noticed my water pressure was a bit high as well. My o2 sensor was getting a little wet as well.
The water outlet holes are drilled in the inside diameter of the pipe allowing the water to splash against the wall on the opposite side.
I elongated the holes toward the outlet end of the pipe. Water pressure went down. o2 sensor is no longer getting wet. Pipes are still cool....



Doug

Opening up the holes slightly is good option, or try regulating the dumps.

140

In my photo the line from the block/ oil pan is going directly to the filter, then to the oil cooler , out of the oil cooler and then back to the block feeding the bearings etc.
The filter is the first thing the oil goes through on my engine which Mercury set up. I did not change a thing. If you install a filter after the oil cooler then you are not protecting the cooler, letting the pan oil go through the cooler and then to the filter??? something not right there. I would check the arrow directions

and I say the opposite, There are no moving parts in a oil cooler, It is just a heat exchanger, water passing thru and oil passing thru it in 2 separate circuits removes the heat from the oil. The only thing that can happen to an oil cooler is rupture or excessive wear over the years. The inside is copper, copper doesn't flake or break apart into little pieces. So if it ruptured the oil filter as you said would be on the outlet would do absolutely nothing. Its a oil filter not a water separator and I highly doubt you would get water in the oil its more like oil in the water due to the pressure difference.
I'll keep mine where Mercruiser designed it to be. This way i know clean oil is going thru my cooler and to my bearings.

We seem to be getting off the subject here..Back to oil temps...I made custom fittings between the exhaust manifolds and the risers allowing me to dump some water overboard thru 2 fittings on each side of the boat. The hose size was 3/8". When that setup was connected my oil temp was 20 degrees less and my water pressure was 5-6 lbs less. reason being, the relief of water pressure allows the water to go thru the cooler faster removing more heat BUT...repeat...My Stainless risers are running a bit warmer at idle due to the reduction of water going thru them...so my question is. Is it ok for the SS risers to run warm at idle??...If so i will re-install the dump lines

I still think proper fix is larger oil cooler.

What is the engine setup? What size oil cooler? What is the ignition timing setup? More timing at idle may help the hot exhaust at idle

509 cu 490 hp each dyno sheet@ 5200 rpm stock 502 merc oil cooler.with power steering..3" x 18" roughly and timing 34degree @ idle locked MSD

People have done this with the rear water ports on some aftermarket intakes...but with a psi regulator. All water goes thru the exhaust until rpm and speed go up, where now the regulators open up.

Now that is interesting...I would like to know more about this..regulators hose size?? and how to set it up. This would cure my problem
thanks

So why not just make the water outlet holes in the tails bigger?? Will lower water pressure. Increase flow through your cooler AND still keeps the risers cool....

Good question, this is what happened..Before I sent both sets of my short risers back to Eddie Marine to have the lengthened I found a new set of long risers on ebay. This is how i new the water holes seemed small. I installed the set from Ebay on one engine and had EM extend one set of my short risers. After i installed them i noticed the set from ebay had larger water holes and more water was flowing out the that engine at idle than the other BUT on the set with the larger holes pipes from ebay they were running warmer than the ones that EM just lengthened.. So i removed them, sold them on Ebay LOL and sent my other set back to EM to have them lengthened. Did that make sense? I guess the smaller holes in the exhaust pipe makes the water flow and fill the complete pipe stopping hot spots while the larger holes in the pipe allows the water to exit too fast leaving some areas between the hot exhaust inner pipe and outer pipe dry or with less water to cool. This scenario also happens when i installed my water dumps, My water dumps consist of a 1/2" mpt x 3/8 hose barb fitting. 1 on each tee fitting where the little black water hose is from the manifold to the riser goes. Dumping water before the risers is just like having larger holes at the end of the exhaust pipe. Let me clarify here. The SS risers were not super hot where you couldn't touch them. Under the elbow bend and on top of the bend a few inches down they were hot but not scorching. This is just at idle, I'm sure once moving they cooled off. That pump pumps 38 GPM @ 3000 RPM'S. How hot is ok...What could happen if they get hot, they are Stainless. As for the aluminum manifolds. No issues they run cool

Here is the data sheet of the oil i'm using. The flash point is 457 deg F and the fire point is 468 deg F so why would 240 be so bad..

http://www.amsoil.com/lit/databulletins/g2883.pdf

and this is interesting also

http://www.synthetic-motor-oil-chang.../#.Vc9T1JeJt80

http://teaguecustommarine.com//media...oij_piping.pdf

If it's good enough for Teague it's good enough for me......

Thanks look at this [ATTACH=CONFIG]544210[/ATTACH]

Line 18 out of engine to filter

Guess Merc and Teague disagree.

I think I just found my problem. Looking at these oil flow diagrams I just realized after 7 years of owning this boat that my oil flow is going in the same direction as my water flow which is WRONG. The oil flow should be in the opposite direction of the water flow to enable it to remove heat efficiently. I have to reverse the 2 oil lines on my cooler, then maybe i'll get 20 or more degrees less in temps.
If you look at the diagram above oil line #6 out of the filter is going to the outlet of the cooler. On my engine it is going to the one at the beginning of the cooler where the water enters. WOW what a find.
amazing I had no issues all these years....
What do you think??

I think that's possible.

Co-current flow is not the optimal path for heat exchange but it may have been sufficient in years past. Now that the cooler has some fouling on it the efficiency drops and you need better exchange.

Looking at the diagram, if you have the oil/ps combined cooler you may have an effective 12 inch cooler which is pretty small for your bumped up power.i doubt if merc put much overkill into the system , especially in warmer waters. Good luck!

I always had mine flow opposite because that's why it is supposed to be .

teague also said synthetic oil made the rollers on a roller lifter slip and not roll.:bong:

I've never found any appreciable difference is oil cooler direction. There are 2 methods of thinking. One is to flow the water and oil in the same direction. In theory, this keeps the same water and the same oil in contact longer so that they can transfer heat. The other is to flow them in the opposite direction. This allows the leading edge of the oil to constantly contact cold water. Like I said, we have tried it both ways on several different apps and have yet to see any measurable difference.
Eddie

Sometimes, its not just about what the oil can handle. Oil has two jobs. Lubricating parts, and COOLING parts.

When you have an engine running at probably 50% of its power output, and its already seeing 240* degrees of oil temperature, I would say something is wrong. Especially, if you are not running an oil thermostat, and your water temp in the block is 140 degrees.

Heat is a killer of valvesprings. According to PAC racing springs, the difference in open pressure, from a spring thats at room temperature, to a spring that is at 350 degrees, can be as much as 90 psi loss on the springs open pressure. So, lets say you are running a basic hydraulic roller cam. Say your springs are 450lbs open at room temperature. Those springs at high rpm, with 350 degree coil temps, may only be 360lbs open. Not to mention, the springs lifespan is greatly reduced from high temperature. Now, the difference between 180 deg spring, and 240 degree spring, may only be 40psi loss of open pressure, but its still something to consider. Of course there are other factors that contribute to spring temperature, but there is no getting around, they rely on oil for cooling.

Seeing 240 degrees of sump temperature, doesn't just mean that, the oil is only getting to 240 degrees. Oil at the bearings can be much higher than that, but you wont see it on the gauge.

I am certainly no oil, or engine expert. When I research things like this for my own stuff, or friends stuff, I tend to look at what the oem's do. Just about every car/truck I have tested/monitored oil temps, are normally within 10-15% of coolant temperature (180-220). Problem with boats, is our coolant temps are not 195*, and we also run under pretty hard loads. So, the fix for this, was oil thermostats, to get the oil hot, and large enough cooler, to keep it cool . Almost every brand of oil thermostat elements out there, and there are tons of aftermarket, and OEM's, range from 180-215* elements. If running 240,250, 260 was good, we would see those elements in the fixtures.

For many many years, oil temperature control, has been a valid concern. From taxi cabs, to pickup trucks, to semi trucks, police cars, or even grocery getters, manufactures combatted high oil temperatures, with external oil coolers. These OEM's have to take into consideration, these vehicles need to last hundreds of thousands of miles. And do so, with the same valvesprings, seals, bearings, and hard parts. Not some guy from the bar who has a built small block in his nova, and puts 800 miles a year on it, and will preach about how great his boutique oil is at handling heat.

There is no getting around, that as oil, any oil, gets up past its optimal operating temperature, oxidation increases. If you said, "after a long 5 mile wide open throttle run, my oil creeps to 240*", I probably wouldnt worry about the setup. But, to say that cruising at 3500RPM, your oil temp is a steady 240*, I would be concerned. It certainly isn't gonna get cooler as you push the throttles down further. Your stock 502 combo oil cooler, was properly sized by mercury marine, for a 390-415HP engine, with stock exhaust, stock everything. It works great for that. Once you start changing things, aftermarket exhaust, more horsepower, possibly leaner fuel mixtures, higher pressure valvesprings, etc etc, things change. Hence my recommendation for a larger oil cooler. I would rather run my oil at a temperature that coincides with oems guidelines, rather than deal with the issue, by running a oil that says it can withstand the extra heat. Just my thoughts on this topic.

Apparently though, what you are saying, debunks the myths here on oso, that "slowing down flow", will actually cool the engine/oil better, than it "flowing too fast". :party-smiley-004:

Great info thanks I did not say slowing down the flow cooled the engine oil better. I said the faster the water goes thru the cooler the oil will be cooler. By using the water dumps it is relieving some pressure and letting the water go thru the cooler faster lowering the oil temps by 10 deg minimum

I am in the commercial refrigeration business by trade and i deal with a lot of water cooled condensers no different than an oil cooler. Instead of removing heat from engine oil it is removing the heat from refrigerant.It is the same concept. Water in at one side and refrigerant out of that side, water out of the other side and refrigerant in on that side. Opposite direction to remove heat efficiently. The Mercruiser diagram previously posted agrees with me except my boat is going in the same direction which is wrong and will be changed. It has to make a difference, that's the way heat exchangers work. Yesterday I was at 3200 rpms@225 degrees and WOT for 30 secs and it went up to 245 . Short blast, boat full of people who don't like to go too fast lol. I have never seen my oil temps above 250-260 even after a hard WOT run. I am going to put my water dumps back in to relieve some pressure and lower the oil temp. I will post the difference with the dumps

https://www.youtube.com/watch?v=_az6A4TKAiE

250-260 on the cold side after cooler is way too much... Get a bigger cooler...

I agree with flowing opposite directions water and oil, on the same hand I agree with Eddie looking at it this way, I cool with 70 degree water flowing through nonstop.... It's gonna cool good no matter what direction it flows...

Cruising temps for me are 170 ish yesterday at 4200 no oil or water stats

You r a rebel Tim:wizard::champs:

When Eddie Young rebuilt my 502, he put in a large cooler and a thermostat. No matter how hard I run it never goes beyond 190.

Padraig