Calling All Whippled 496 Owners
 

I have a (non Whippled) 496 with similar horse power and a big oil temperature problem at WOT even after extensive modifications to improve the situation. I am looking for any Whippled 496 owners that do not have an oil temperature problem when running at WOT for extended period to learn what works.

How long are you staying in it at wot?

After about 5 1/2 min @ WOT the oil temperature hits 280F and is still climbing. This is only testing to see if there was a thermal saturation point where the oil temperature would stabilize and stop increasing at WOT. I have not found it yet and I will not go above 280F even during brief testing.

ttt

Rage,

I too experienced quicker rises in oil temp after additional hp was added.

For the sake of error on conservative side and with obvious interest in keeping an engine as long as possible, I made the personal rule of backing off to mid 3's when the guage at the helm reads 200 degrees. At this point it's actually about 20-30 degrees hotter per temp gun. Sounds like our temps are almost the same because I don't remember last time I held it open for solid 5 minutes.

Going from stock to all the Raylar stuff, it now takes less time to get there due to the extra heat being generated. Just over 5 minutes of wot is enough for me. We rarely run that much as it seems like eternity to hold a boat engine open that long.

Of course, many will disagree with me but that's just how I feel about it. For me, 5 minutes is probably somewhere around 7 miles and if you need to run wot longer than that than you're just gonna have to plumb the system to cope.

I use the stock oil cooler etc. Are you using it as well or did you buy something else?

My question is: how long do you want to run it open? It's a matter of how often do you want to buy or build an engine right??

Also, I've experienced a huge difference in different oils. It does make a difference.

Thanks for the input. Actually we have have dicussed this issue earlier in detail on another thread as well. I have the Hardin Marine thermostatically controlled 3x18 oil cooler (supposedly rated for 700hp), added AN-10 oil lines and fittings, added a 5/8" dia 'T' fitting water dump hose at the oil cooler hose's sea water exit point to increase sea water flow through the oil cooler, enlarged the Bravos lower water inlet holes to 0.29" and plugged the Bravo's upper (above water line when hull is planeing) sea water inlet holes. Coolant stays in the 140F's but oil 270F and still climbing when I blink and shut it down.

I am just trying to find out what it takes to keep the oil in a closed cooling ~600hp 496 cool enough for extended WOT running. Then I will decide if it is worth it. I have yet to find one that I can confirm will do so.

tt

Ok, I remember that as well...

For what it's worth, all coolers are not created equal. Certain alloys dissipate heat quicker and more efficiently. Hence, you can find some larger ones that are cheaper than smaller Mercs. It's not just the size of the cooler but the type of alloy blend that it's derivative of.

I remember you started out with the stock 496 cooler I think and then moved the the one you have now. Is the Hardin a honey comb type or the other style?

Another thing to consider is slowing down the water flow slightly. There can be a fine line between just passing water over the rods quickly vs. letting the water "absorb" the heat before moving on...

Also, did you install a higher pressure by pass valve in the block or did you leave the stock one in there? The remote filter assembly poses some resistance itself and a larger amount of your oil (not all of it) could be not even making it into the filter which is why you'd typically upgrade that valve.

I use the stock oil cooler and don't really have any problems with it. One other thing - - Are you measuring your temp coming out of the block or going in? Mine reads around 200+ going in but closer to 300 coming out.

I use AMS Oil 20/50 and can run for a while without heating it up.

I ran that as well for the last two seasons.

Thanks for the input. See above.

I have whippled 496 ,s they make 800 hp all coolers stock ,except my heat exchanger is 5 inch I start to see oil temps after 7to 10 miles at 96 to 100 mph then I run negative boost for about a mile temps come right down lean on again things happen fast at that speed I have to pay attention I watch my temp gage more when it starts to rise over 150 I go negative I also run 120 thermostats

Rage I looked at your numbers twice just to make sure.. If I'm reading this pdf file correctly, you're in good shape. The guages always are off some.

Your real temps look awesome to me. Perhaps I'm reading it backwards??

Not to mention you are quoting "out". All you ever really care about is what's going back "in".. That is unless you have 300+ coming out which clearly you don't by the file you shared.

If possible, make sure the water and oil flow in opposite directions in the oil cooler. Much more heat extraction that way.

Would you happen to have a pic of the larger heat exchangers? Are they Sendure?

they are sendurs you might find pics under clayola crazys new headers

Hey Crayolacrazy, thanks for the info. Wow 800hp 496!

What is the oil temperature and oil pressure "after 7 to 10 miles at 96 to 100 mph" when you decide to run negative boost to cool things down? Is that the heated oil temperature coming out of the engine or cooled oil temperature going back into the engine after the oil cooler? What is your sea water pressure at the 96 to 100 mph? What drives are you running or are you running seperate transum mounted sea water pick ups for everything or just the intercooler or...?

I also am running the 120F thermostat.

Sorry for all the questions but I am getting desperate.

Pictures welcome!

Thanks,

Bill

Keep in mind that my data stops at ~280F 'out' oil temp because I arbitrily reduce speed from WOT when I reach that number to cool down the oil and that the oil temp is still climbing at that point. The max oil temperature that my engine will stabilize at is an unknown.

I am relatively new to the high hp marine performance engine game and rely on opinions of seasoned high hp marine performance engine people. There are widely diverse opinions on max engine oil temperature limits. Opinions differ on whether oil in or oil out temperature is the most important. Oil out /crankcase temp proponents seem to be greater in number. Individual opinions on the maximum allowable oil out temperature range from 230F to 300F. The mean seems to be ~250F and rarely higher than 280F so that is my personal arbitrary limit.

There seems to be three significant issues related to oil temp limit: damage/oxidation/breakdown of the oil, damage to delicate engine components (seals, hoses, plastic parts) and damage/high wear do to loss of lubrication (low viscosity/oil pressure). Hot oil viscosity rating is tested at 212F. I have seen custom tests run at 300F and the viscosity of all engine oils, including the best synthetics, drop to low single digits and all the oils are within a unit of viscosity or so of each other. The high end synthetics will oxidize/breakdown at a much slower rate than the lesser quality dino oils, particularily at extreme temperatures. Since the viscosity grade of the synthetic is inherent and with dino oil achieved with modifiers the later is more susceptible to falling out of viscosity grade from extreme temperatures.

My goal is 250F max oil out temperature at extended WOT running.

Maybe I am better off than I think.

I recently performed a hot oil bath calibration test of my dash oil temp gage/sensor versus a quick tip thermocouple both immersed side by side in the heated oil. The gage proved to be essentially dead on accurate for test range of 140F-280F. As on my engine I had a dedicated ground to the battery for the sensor and ran the same 13.4v battery voltage as the boat produces at WOT

You know, that makes total sense to me. However when I discussed this with Hardin Marine tech people thay said that they tested both ways and found zero difference in the drop in oil temperature in temp minus out temp. Also another seasoned engine builder said the same thing. Mine is currently parrallel flow but I may try the reverse flow (a more difficult plumbing problem for my install) since I am running out of inexpensive things to try.

ttt

Countercurrent flow is a fundamental law of thermodynamics and nature. In other words, it has to make a difference. The degree of that difference is the question. Worth a try I would think. Concurrent flow cannot remove more than 50% of the heat at best, usually much less, countercurrent can remove 95%.

Yep. Worth a try.

Anybody else?

I would really like to talk to Crayolacrazy about his set up. Email sent , his PM box was full.

ttt

Well per the attached Merc Service Bulletin, 250F - 280F crankcase oil temperature is "normal" for Merc high performance engines. 300F oil temp is the red flag point per Merc. In that case I am done fooling with it.