Jet Black 496ho Oil.....

[nwimbush]

Rippem
No soot is interesting.
The crankcase fumes substantiate the theory that there is a localized overheating of oil within the crankcase. Once the oil has had the light ends burned off, the smell subsides and the oil has turned black.
If this is common with this bore/stroke combination I would consider changing compression and oil rings - don't know what you typically run, but try gapless.
The difference between the 454 and 496 is stroke, bores are both 4.250. Perhaps the lengthy stoke is causing piston "wobble", which would again allow cylinder wall oil to become overheated and turn to black stuff/bad smell? Boring these puppies out might actually improve the situation and reduce the obtuse angles with the bore/stroke combination.

[GCAT911]

IAC purely controls idle. It is a pcm out put regulate solenoid and has little to do with a lien or rich mix. We have seen that when synthetic oils are used after running standard parafan based oils the oil rapidly turns black. This is beacsue the syn blends strip away the HC (hydro carbons) inside the engine that the standard oils leave behind. On the second or third oil change using Syn oil the dark oil problom is no longer an issue. Also engines that do not generate enought heat tend to create sludge witch build inside the engine. This is also a problom with boats that are not used much. All these factors create dark oil.

[monstaaa]

Originally Posted by snapontoolsjt

but... if the oil cooler was restricted with seaweed or eel grass, the oil temp guage would tell you because oil temp would go up due to the coolers less ability to cool unless there was a trivial amount of debris in there which would not show up on temp guage cause the oil was running normal temp.

not true.

over this summer i had atleast 20 incidents of cloged coolers. 20. most of them 496's some 525's . the guages in these cases didnot reflect actual temps of the oil on the 496's. for what ever reasons 525's have a better and faster reaction time from a sending standpoint.
i found p/s coolers loaded as well as the oil coolers and heat exchangers , in that order, thus creating a slugish or diminished circulation of raw water. yet not enough to show high e.m.t's or guardian. allowing the cooling ability to diminish. no reflection in the engine coolant temps either due to the closed cooling.

[SDFever]

Originally Posted by monstaaa

not true.

over this summer i had atleast 20 incidents of cloged coolers. 20. most of them 496's some 525's . the guages in these cases didnot reflect actual temps of the oil on the 496's. for what ever reasons 525's have a better and faster reaction time from a sending standpoint.
i found p/s coolers loaded as well as the oil coolers and heat exchangers , in that order, thus creating a slugish or diminished circulation of raw water. yet not enough to show high e.m.t's or guardian. allowing the cooling ability to diminish. no reflection in the engine coolant temps either due to the closed cooling.

then if you ran it with an sc guage and/or cds it would have to show some funky sypmtom - even water pressure is affected at that point if there's enough debris to cause a problem. by the time the engine goes into guardian due to heat, it's already possible that there has been some damage but how much?? That depends on lots of things. i'm not saying you can fix everything with a scanner but if there is enough crap to clog something that is part of the sending unit harness or if the sending units are not accurate, i personally would at least notice a difference on temps with sc in my boat. i'm not at all familiar with your units that you guys are servicing. i'm speaking of mine. this isn't it. keep going though.

[SDFever]

Originally Posted by nwimbush

Rippem
No soot is interesting.
The crankcase fumes substantiate the theory that there is a localized overheating of oil within the crankcase. Once the oil has had the light ends burned off, the smell subsides and the oil has turned black.
If this is common with this bore/stroke combination I would consider changing compression and oil rings - don't know what you typically run, but try gapless.
The difference between the 454 and 496 is stroke, bores are both 4.250. Perhaps the lengthy stoke is causing piston "wobble", which would again allow cylinder wall oil to become overheated and turn to black stuff/bad smell? Boring these puppies out might actually improve the situation and reduce the obtuse angles with the bore/stroke combination.

"piston wobble" - - - - - -

we'd have more than dark oil to clean up. there'd be connecting rods flying through that oil pan supposedly full of residual. that's one way to get it all out though.

[SDFever]

anybody read the oil lab results in posts 15 & 16. they're attached as word docs.

[Anger Management]

Yes,I did read all the attachments you posted on 15 and 16...very interesting.
How much are they chagring for each analyisis?

[monstaaa]

Originally Posted by snapontoolsjt

then if you ran it with an sc guage and/or cds it would have to show some funky sypmtom - even water pressure is affected at that point if there's enough debris to cause a problem. by the time the engine goes into guardian due to heat, it's already possible that there has been some damage but how much?? That depends on lots of things. i'm not saying you can fix everything with a scanner but if there is enough crap to clog something that is part of the sending unit harness or if the sending units are not accurate, i personally would at least notice a difference on temps with sc in my boat. i'm not at all familiar with your units that you guys are servicing. i'm speaking of mine. this isn't it. keep going though.

not in all instances. these few i am discussing were equiped with smart craft. as well we diagnosed with our lap top. niether came up with d.t.c's but yet their was black oil and stalling issues. the i.a.c's were functioning electricly however machanically werent. the plungers were frozen due to saltwater corrosion.
not saying this is the answer, just the aswer in these cases.

[minxguy]

Originally Posted by snapontoolsjt

anybody read the oil lab results in posts 15 & 16. they're attached as word docs.

Yes I have read them and according to the reports there is no fuel dilution or buildup of solids, I feel that this may shoot down the idea of blow by.
I do not like the way this lab presents the numbers, espcially when it comes to viscosity. They use phrases like "should be" and "universal average something".
I personally don't care how my oil checks out to an average of everybody elses oil. I want to know what my oil is doing and if I have had more than one test done by this lab I would guess I would then get a history on my engine.
What I did notice about the oil reports was that on page 2 the sample in the right hand column (dated 3/31/07) the use oil viscosity (68.6) was BELOW the lower specification for a 40 weight oil at 210,and this was with 10 hours on it. Not good, the oil has fallen out of grade. The SAE says to be a 40 weight the SUS for the grade is 70-85. You ended up with a real stong 30.
This could be caused by fuel dilution, but the report does not suggest fuel dilution. I am guessing that the oil was a marginal 40 when new and has polymer shear in 10 hours of use.
Ray is correct, you should do an oil analysis on your new oil so you now have a base line to compare your used oil to. I don't think that you want to compare to a whole bunch of test results that make up an "average".
While I also came to the same conclusion that the light ends are burning off causing oil smells I find it hard to belive.
What I am going to look into is that the oil is turning black quickly because of the additive package or a particular componet in the package.
Also the word black is subjective. A down and dirty test for "dirty" oil is to stick you finger in the waste oil, if you can see your fingerprints the oil isn't dirty. If your finger looks like it was dipped in black paint, you aren't changing your oil soon enough.
Ken

[Anger Management]

I'm not trying to jump in the middle, but I have had the computer scanned three times last summer. The only fault was a cam sensing issue which they cleared. The IAC was not an issue. I thought the IAC would have been an issue since the Mercury Manual descibes it as a possible cause. The new ECM that is know installed resulted in a 100RPM increase over the old EMC, but the dirty oil is still an issue. I have also changed my water pump guts to make sure proper cooling was being conducted? The impeller was set in it's ways, but nothing was missing off it. My spark plugs were changed and they were grey in color, but the gap was off a little, .080..new plugs were installed with the gap set to .060 as the book states.