higer oil temp after rebuild, bypass??
 

Have a friend with twin 500EFIs. One was rebuild top to bottom this past winter, the other got a top end fresh. Now oil temp is 50+ degrees different, not off the charts but different. He is running in real cold water (Great Lakes) 52 degrees. Oil temps on hot engine runs 190 to 230 and climbing when running hard. Cool engine 150 to 180 running hard. Water temp is exactly the same, exactly. He is concerned that later in the year, doing runs on warming water will give him serious issues with hot oil. I don't want to debate how hot oil can get, just want these engines to match as they used to.

A while back I read something on here about a bypass that has to be reinstalled on marine engines where the engine block filter housing would be? I searched but can not find it. Can someone explain what this is? Is there a chance the builder left it out? Can it be installed with engine in the boat or is it internal?

Thanks

http://www.offshoreonly.com/forums/g...-hardware.html

The bypass you are referring to is a 30lb unit that replaces the 11 Lb many of the truck engines come with. If he has the two 11 lb bypass valves installed in the filter block on that one engine that could very well be the issue.

The proper way is to remove the middle bypass valve leaving it open, then either install a 30lb valve or placing a plug in the inboard hole closest to the pan rail side.

http://www.ebay.com/itm/390855596324

Installing the 30lb valve is my preference.

when the rebuild wes done was the origional bypass used and what kind of oil temp did he see before the rebuild?i would suggest checking the grounds at the dash and replacing the oil temp sending unit ,the oil temp might not be as hot as the gage sais it is.

That is good info, thank you.

Still wondering what a builder may have changed or left out however. The engine was rebuilt as stock, to match the other one.

Yeah what mike said would be the smartest approach, followed by the other suggestions contained in that link. Might as well start with the easy stuff first. Seems like quite a few here have had erroneous readings regarding high oil temps lately.

Borgi don't wan to beat a dead horse but i will still ask :D if i remove the 11lb valve and install the 30lb valve do i have to plug the inboard hole thanks rod

Not at all! You want to remove the center 11lb bypass all together. Then install a 30lb unit on the inboard hole. This will direct full oil to the filter pad/adapter, hence oil cooler. You will never overcome the 30lb valve in a healthy engine. It's an issue of what fits in there better really, and the bypass valve is a perfect fit and inexpensive.

So as you can see, plugging it (outboard hole) or installing the 30lb bypass valve, is all a matter of preference.

And to give credit where it's due, Smitty(arcticfriends) did a lot of testing to come up with all of this great info. It's crazy what a wrong bypass valve and improper oil line sizes etc can do to your oil temps. One last thing I will add to this, mark from MER Performace uses Schumman oil pumps, and recommended I try one. One of the cool features of these pumps is an external bypass(vs bypassing oil back down the oil pickup tube). I'm curious to see if this translates into decreased oil temps. In other forms of Motorsport this seems to be a common finding.

Are you noticing a difference in oil pressures between the two motors? I am curious about the pressures at idle, cruise, and WOT when the temperatures are different.

oil pressure is the same at all rpms/ temps

If pressures are exactly the same I'd think he has an indication issue.

That would be my thought also. Time to take the infrared gun to the filters and see how far off they really are.

Thanks for the help guys, I have advised him to do that. Easy stuff first right? :D

Totally agree with what Borgie is saying here and especially about the Schumman oil pumps as they do oil pumps all day long. They also are doing some cool stuff for oil pumps on the LS engines as well.

I took a class that they put on last year and it was very informative as to how they are improving stock oil pumps along with some of their own designs. A lot of info about internal pressure spikes within the oil pump itself that want to combat. Anyways they have been around a very long time.

double post

Also make sure water flow is still running opposite of oil flow in coolers, besides that I would look at 11lb valve issues.. make sure 30lb valve is used, if not sure then just replace it anyway with one....how much time is on it Ron? before he runs it again for the 10.00, cut the oil filter open and make sure that's all good and there isn't a reason for hot oil.....

another suggestion would be to make sure Teflon tape was NOT used on the oil temp sender

they are designed to be installed dry. the sensor needs a good connection from the block to work properly.

With the #'s given I'd be more concerned with the too cold motor. IE: 150°-180°F running hard.
If not gauge or sender, could be the oil t-stat.

When properly setup, oil temp should ,reach max temperature and stay there until the boat runs out of gas. it should not continue to climb into the danger zone.

I would have to agree with checking the sending unit for proper ground, along with the oil temp gauge for proper ground to start. Sounds like you covered the basics with the impeller and water flow. The thermostat element can be changed, i wanna say they are about 30 bucks or so. Bad thing is I think on the 500EFI the element is in the block adapter, which would totally suck accessing to swap it out i would think.

That element should be fully opening allowing full flow to the cooler, around 210*. They dont start opening till around 180-190. If its not electrical, could very well be the element simply isnt opening, and never allowing full flow to the cooler. In the cold water we boat in, I wouldnt be surprised if that engine isnt seeing 190-230 running without an oil cooler (stuck oil thermostat).

Mr Forbus, I have tested the element before in a pot of water and recorded the temp/movement of the element. That test is 2 years old and going off my memory. I have a brand new mercury 8161631 element here on my desk. I will retest now, and report back. Stay tuned.

Update. Oven thermometer wasnt working. Attempted dissassembly. Metal housing on thermometer sliced thumb open, blood everywhere. Thumb not looking good. Hurts. Wrapped in gauze. Looking for new thermometer.

This is how most of my experiments in the name of science work out.

As you must know already, if you don't bleed, you didn't do it correctly.

Also, be more nervous about no bolts/nuts left over than having some left over.

is it possible that newer tighter motor, less oil spraying around and more staying in the bearings longer gives oil more time to heat up?

I agree shoot the filters with a temp gun first. Also, while unlikely, is it possible that one engine is reading the temps after the cooler and one before? Maybe hose routing after the rebuild?

Oil stat element fully opened just before the water boiled.

How is the boo-boo?

I would shoot a temp gun at the oil pan, oil filter and the sender compare that then compare against the other engine doing the same.. This would be the easiest and first place to start as others mentioned.

lol, its not bad . At first I thought stitches, but then realized I was being a puzzy. Its a minor slice. :helmet:

Put some RTV in it than wrap it with duct tape.

Done

direct from the 500EFI merc manual

Oil temp at 5200RPM=170-180*. (Full throttle)

I dont know how mercury racing got away with those temperatures. On oso, you need 250* oil temps or your engine will get milkshaked, not lubricate properly, and destroy itself. You need to get high oil temps to burn off the water coming in from your poor choice of camshaft selection thats reverting.

Page 76.

http://www.mercuryracing.com/_media/...5010%20500.pdf

Which brand RTV would you suggest? Is ultra black ok? Or ultra grey? Or Ultra blue? Or hylomar? How much should i use? Where is budman anyway?

Toyota FIPG.

I put that $hit on everythiing, including french fries. Made from the best stuff on earth, unicorn powder and the tears of Toyota executives after the gas pedal recall debacle.

I'd stick your wound in a can of carb clean. You won't worry about the bleeding part of your wound anymore.

Remember, they measure temp after the oil cooler...not at the pan or before the cooler.

And how old is the 500efi now?.... Just saying old design, old thinking. They now use a 210 and I really doubt it has anything to do with tight tolerances etc. I've said it many times, oil has an optimal operating temperature ie 100 degrees Celsius. Doesn't matter if it's fancy synthetic or conventional. Even if you don't get milkshake you still form acids from the moisture present and left over by cold oil temps. Cold oil doesn't lubricate better to a point.

I find folks here like to use the old analogy "well it worked for me". Gee that's real scientific and factual... I guess if that is good enough, so be it, however there is science behind the theory of running oil at 212 degrees. Just because "some" big engine builders don't use oil t stats or recommend ones that keep oils temps down in the dumps (with zero supporting/validating data) doesn't mean squat to me. Some of these same builders thought synthetic oil would make lifter followers "slide" on cam lobes..... That one made me laugh first time I saw it.

If cold oil temps work so well for everyone, show some examples of case where warmer 210-215 degree stats damaged an engine. There is plenty of data showing optimal oil temp (212) actually adds to the longevity of an engine, marine or otherwise.

Oh and mild, not an attack on you here, I honestly would like to see some data validating cold oil temps because everything I've seen speaks to the contrary.

Good reminder for everyone

Changed what? The 500 efi uses the same element as the 525efi, 700sci, and new 565.

You can sit here and argue your theories with me all day long. How many mercury racing engines are out there doing poker runs every weekend, racing on the course, and overall pleasure boaters beating the snot out of them. Compare that to how many borgie engines or mild thunder engines are out there. One thing about mercs engines , they may not be the most powerful , they may not be the best components, and may be overpriced , but one thing they are NOT, is time bombs exploding all the time.

There's more to the story than the simple temp of the oil from a flow/lubricating standpoint. Keeping the valvesprings cooler, pistons cooler, rocker arm bearings, lifter wheel bearings, and other things cooler, might be more beneficial than the viscosity/lubricating deal. Mercury marine has ALOT of money behind them, and a lot of money on the table when it comes to testing, designing , and warranting these engines. Especially the racing engines .

But to get back on topic, 4bus' s buddy who's seeing 230 temps, is outside the manufacturers oil temp specs by quite a margin, which would indicate something isn't functioning as it was designed. 230 temps after the cooler would alarm me also.

Mercury is using a higher set point for T stats in the news engines as far as I know. Must be a reason... I agree that his oil temps are outside of the recommended range after the oil cooler.

where did you get that info? You can go online and compare the oil thermostat part number for every engine they made with an oil thermostat. From the HP500 all the way up.

FYI the new 1350 also uses the same thermostat element as the 500efi. The 1075sci uses the same element as the hp500, 600sc, 800sc engines from 15 plus years ago. They share a similar housing mounted on the back of the cylinder head hence the different part number the 500efi,700sci, 525efi, 1350, etc. Those use the block mounted deal with internal stat.

Mild, if u get a cut bad enough that it requires stitches soak a rag in lacquer thinner then wrap it this will get U2 the hospital without bleeding all over the car. For minor cuts (even major) the best thing is super glue, has to be the original. Nice dab of super glue and its back to work. These are the techniques that men use and not for the faint of heart...