Oil temp problem in my 572, need input/advice....
 

I have been posting this issue in the HP500 Oil temp thread, but have not been getting any feed back, and I looking for some iput/advice.

Went out yesterday and got the following results:
1. Still no oil temp on gauge, gauge works, I ground the lead, and the neddle goes full over, Gauge is a 140-340 temp Livorsi
2. Oil Pressure at start up is 70-80psi, after running at 3000-3500 rpms, it drops to 60 psi, ( not sure if this really a problem).
3. After 3500 rpm , come back to idle, I get 40psi of oil pressure at idle 900 rpms.
4. Water temp is a constant 140 deg.
5. Bought an IR temp sensor/gun ,and shot the following readings after the 3500 rpm cruise with the engine off
a. oil filter:180 Deg.
b. oil thremostat housing: 185 deg.
c. Oil cooler: 85 DEG!
d. engine block: 120-145 DEG,
e. CMI headers: 85-90 degs
f. oil pan: 185 deg.
I run Mobil1 15-50wt oil in a 12 qt oil pan, this oil change has about 10 hours on it...
Engine dumps ALOT of water out the exhaust, and I have a water pressure dump valve set at 25 PSI.

NOW what really has me concerned. After watching the airshow, (Thunder birds were great). I headed back to the house, and ran 3000-3500, for a most of the way, (oil pressure sitting at 60-65PSI) I opened it up to WOT, hit 97 MPH for about 30 seconds, BUT the oil pressure starting DROPPING, down to 55PSI, so I backed down to 3000 RPMS, (55 mph), for the rest of the way home. After 5 minutes of this cruise speed, oil pressure came back up to 60PSI. This is the first time the oil pressure drop has happened while I have been trying to solve my no oil temp issue. Kinda scared me. At idle back at the dock, I get 40PSI of oil pressure, and oil pressure goes up as I throttle up...
I think that my Oil thremostat is not opening, how does I test it, besides removing it and boiling it in a pan? or is there something else going on?
Looking for some ideas, advice..
Thanks,
Dean

What is your oil thermostat opening temperature? If the temps are only getting to 185 at the filter and your T-stat opens at 210, the cooler is not going to get oil flow. It sounds like temps are just not getting that high. Also, your drop in oil pressure could be from foaming the oil. Bob Madara and I had a lengthy conversation about this and he recommended switching to Brad Penn oil as it has better anti-foaming properties.

Another data point to gather would be oil temp at the pan.

Matt,
I shot the oil pan with the IR gun and it said 185. I don't know if the Oil thremostat rating is or if it is even opening. Any ideas on how to confirm if it is opening?
Thanks,
Dean

Heres my guess at whats happening. At cruise, everything is working as it should. The oil stat is allowing your oil to warm up. However, at wot, now the engine is making some power/heat. The oil stat is sending oil to the cooler, but my guess, the cooler is too small, not providing ample cooling. Therefore the oil is getting too hot, and showing a loss of pressure. Once it cools back down, pressure comes back. The idea is use a oil stat to warm the oil until the demand for more cooling is needed. Then its the coolers job to keep the oil close to the operating temp of the thermostat element

dean, oil temp of 185is ok.i like to see 190 to 210.i agree with matt that the oil may be foaming.i would try brad penn,kendall,or valvoline,all 20w50 and see what happens.

could be a simple sensor. they do operate on different ohm ranges. make sure you have the right sender.

Mike,
What causes the oil to foam? The oil that was in the engine when I bought it was Kendall 40 Wt straight. And never had this oil pressure dip problem at WOT

The oil cooler is off a HP500 bulldog

Any chance it is a windage issue at high RPM's? What pan and windage tray are you running? Since oil temp seems to be OK when checking the pan, this is where I would look.

M,
I talked with Liviorsi and they gave the Ohms readings I took out the sender and boiled it and got the Ohm readings I was suppose to.... i think the sender is good....

This engine started out as a HP500 bulldog, and bulldog comes with a Melling high output unit,the bulldog came with a 12 qt Merc. cast aluminum oil pan

So stock 500hp cooler now on a 572ci making ?????

If you suspect oil foaming, trying running the pan 1 quart low on oil and see if that helps.

Am i correct in assuming you havent checked oil temp at wot ? Or you did?

HM,
The 572 Dyno'd at 680Hp, attached is the Dyno run sheet. And right now the oil is about 1/2 qt low, (oil level is 1/2 way between low and full on the dip stick). And I can't check the oil temp at WOT with the IR gauge, my oilt temp gauge never moves.....

My guess would be the stock cooler isnt enough to support nearly 700hp. But without the Oil temps, just a guess

Check the resistance at the meter, I had a similar problem and I found a break in the wire inside the insulation. As far as Kendall oil, I hate to go here, but I used to run Kendall Racing in my Trans-Am and it had horrible viscosity stability. I run Amsoil Dominator 15w-50 in my 524 pushing 700hp. My cooler is actually a little small and after a hard run my oil gets up to 270 but pressure stays constant while running. The pressure will drop at idle to 20psi for less than a minute when I drop to an idle, as the cooler catches up the pressure comes right back.

When I shot the oil cooler with the IR gun yeterday after 3500 rpm cruise, it read only 85 deg. That is what is making me think the oil therostat is not opening at all.... The oil cooler is not even hot to the touch, but the oil filter is and the thremostat housing are both reading 180-185 deg. after the 3500 rpm cruise....

TIL,
I have verified the gauge and the wiring is good, according to Livorsi, if I take the lead off the sendor and ground it on the engine somewhere, the gauge neddle swings full hot, so Livorsi says the gauge and wiring are good, and I talked with Liviorsi and they gave the Ohms readings I took out the sender and boiled it and got the Ohm readings I was suppose to.... i think the sender is good....

Is the filter pad bypass plugged or are you running a 30 lb. bypass valve? I ask only because I've seen this problem where the bypass valve was left out of one engine. Starboard engine would hit 210 on the guage, oil cooler t-stat would open, and oil temp would drop to 180. Port motor oil temp wouldn't budge. Filter pad bypass was never plugged and no bypass valve installed. Put plug in bypass hole and port motor built oil temp just like starboard. Oil temp sending units were located on remote filter housing.

That is 2 Q's I don't know, I'll try to check it out

Bingo .. that's it change t-stat its like 25-30$ just went thru this. t-stat closed, no flow to cooler..go to BAM web site put in HP500..u will c a diagram of the filter/housing with the t-stat set up. it has a spring that holds it in place, but also keeps a non functioning t-stat closed. its essentially a diverter valve.

ask him to send you a new sender

I,
I just called and ordered 1 and the O-ring also.
Thanks for your input.
Dean

M,
I saw your post and for $14.XX I ordered that also.
Thanks,
Dean

Quick and easy way to check flow to cooler,touch test on the inlet hose. Not sure if it bypasses all or most when spring is closed, but if you're only seeing 185 after a run I'd think it's working.

The oil thermostat may not need to be open at 3500. Mine doesnt open till im running hard.

Check for a poor grounded oil filter pad to motor.

True , but his cooler never gets warm...so no hot oil passing thru...to warm it.

the 15 50 oil has a lot of friction modifiers and when they start to break down the pressure will drop.im no oil expert but i would say the straight 40 oil did not drop in pressure because it has very little friction modifiers.i also suspect that when the breakdown is happening the oil starts to foam up causing the drop in pressure.this is why i suggested the 20w50 and the brands i did.i have used these oil,s with great results.i will also add that todays multi weight racing oils are rated at about 200 degreese before they flow like 50 weight oil.also,when you shoot the oil cooler with the ir gun it is reading the water temp,not the oil temp,that is why it shows 85 deg,that is the incoming water temp.try one of the brands i suggested in 20w50 and let us know if the pressure drops with the same running conditions.this is just me thinking and i may be all wrong or maybe right on?

i might be wrong but i think the bulldog pan is a 10 qt unit.2 xtra qts will cause oil foaming.

Mike I think you were meaning to say viscosity index improvers (ie VII), not friction modifiers. Oils with a large spread in viscosity, and they usually tend not to be a high viscosity index synthetic base, will rely heavily on viscosity index improvers to perform at varying temps. A good quality synthetic will be devoid of viscosity index improvers and this be a shear stable oil. However, the BBC is a low shearing engine design and as such something else, probably temperature is to blame, not the oil itself, beyond it being an antiquated straight weight.

Redline synthetic is one of the most shear stable on the market and uses zero VII's. And regarding running straight weight, DO NOT DO IT! Straight weight oils are for racing only where a pan heater is used. They will only exacerbate wear in a marine Performace engine. With all of the quality synthetic multi grades, straight weights are 60's tech and should remain there. Just remember guys, not all "synthetics" are created equal regarding VII's.

A great article regarding VII's : http://www.machinerylubrication.com/...ndex-improvers

And I think Mike is spot on regarding your oil foam being possibly the culprit of windage. Modern motor oil doesn't tend to foam unless heavily contaminated with another fluid, or mechanical stirring, or windage is present. Please Note* Oil aeration(ie foaming) has been well documented to cause large increases in fluid temperatures. Food for thought. It might be the issue or a contributing factor, but it does happen.

In closing, I suppose the real question to ask is, do you need some fancy oil to cure an issue that's likely related solely to your oil t stat/ or crank windage causing excessive temps? Definitely move away from a straight weight, however any conventional oil in the 40wt range (multi grade) ie 10w-40,15w-40..will suffice. Let us know if the parts ordered cure your ills.

True an over full crank case in any engine will get aerated and foam due to interference with the recp. assembly. A problem none the less. but maybe not his re: high oil temps. 20w-50 v-twin Mobil is a good example of a stout product that stands up well in our marine conditions.

Yes actually oil aeration can cause a spike in oil temps. Very common issue in racing!

Just an FYI. I've been running vr1 40wt in my motor all summer. Needed to do an oil change and got a heck of a deal from an OSO member on 20w50 Bradd Penn. I have a 16qt system so an oil change can be pricey that's why I bought the Bradd Penn. Went from 60 to 70psi at idle and 75 to 90 at WOT. Oil pan temp went from 250 WOT to 220. I wouldn't believe it unless I seen it with my own eyes. Deal or no deal I think I know what oil ill be using from now on. And the nice thing with the green oil is I can actually read the dipstick.

I think we are stroking ourselves until we get some true temp readings at wide open throttle. This is when his oil pressure issue happens. Temperature can have a direct impact on the oil pressure. Most BBC engines Ive seen, hold a pretty consistant oil pressure from 3000-6000RPM, when the temperature is steady. When my oil is 120*, and i get up on plane at 3000RPM, my oil pressure is in the 90's. Once it gets up to 190-200 degrees, its in the 70's at 3000 and 5500rpm. If you are getting say, 250* at wot, I can see it losing some oil pressure, compared to what it is at 185*.

The stock oil cooler is probably a 2x17 or 2x21 case. On a 700HP engine, I'd be running a 3x18 style cooler. A stock 2x17 cooler, is ok for a 400-500HP engine. At cruise speeds, you are well within the limits of the cooler, at wot, probably not so much.

Also, the stock fittings merc used on those cooler applications, suck as far as oil flow. The idea of an oil thermostat is to help maintain a steady oil temperature in all conditions. In our cars, we run say a 195* stat. We see 195* on our temp gauge. Now, remove the stock radiator on your tow rig, and install a radiator from a honda civic. I dont care what temp thermostat you install, its gonna exceed 195* temp.

Thanks guys for all the input. Here is my plan of attack:
1. I bought some Kendall (13 qts.) GT1 20-50 Wt oil and will use a Merc racing oil filter to change to after the Oil Thermostat change out.
2. I will go Mystic and pick up my new oil thremostat and sender for install this week
3. I confirmed with "Chris" Merc. Racing yesterday, (Nice guy by the way, we talked about 15 minutes about my oil issue) that I do in fact have a 12 Qt oil pan. There is a misprint in the Merc racing HP500 BD owners manual that I have that states its a 9 qt oil pan. I have attached a pic.of oil pan
4. I do have standard HP500 bulldog oil cooler that is 2x17"
5. I'm thinking about relocating my Oil temp sendor to the Oil pan, you can see in the pic of the 2nd boss available in the pan for that install. The other 1 is used for my oil drain hose.
6. Ensure that my Oil thremostat pad has a good ground.

Besides the oil gauge not working I don`t see any issues with the readings you posted.
Oil pressure is good.
Oil temp at 185* is fine
Drops when running hard= normal (oil heats up, gets thinner , oil pressure drops, mine drops to 50psi)
Drops after hard run @ idle =normal (mines drops to 20psi after a hard run with spring oilers)
Goes back up with some throttle= normal
You have 85* at the cooler.. unless the water you boat in is that temp looks like oil is running thru the cooler.

So besides the gauge I dont see what you`re worried about.

To test mine I take the sender out and drop it in some boiling water along with a thermometer and check against the gauge.( use an alligator clip to ground it)

+++1

I think the concern is the fact the oil pressure is dropping while being at wide open throttle, along with unknown temps at wide open throttle. I agree 185 is just fine at cruise. Ive seen boats cruise with oil temps that were just fine. However at full kill almost bury the oil temp gauge at 300 degrees at full throttle thanks to a lean tune up and the pistons glowing red. Few seconds later a rod cap let go and put a rod thru the oil pan on this particular setup.

If im running along at 4000rpm with my oil temp gauge showing 190, and oil pressure at say 70psi, when i nail it to 5600rpm for a few miles, oil temp goes to 210, oil pressure stays at 70psi or better. I personally do not want to see my oil pressure drop when i advance the throttles to a higher rpm. A properly setup oil system should not lose pressure as rpm increases. Just my opinion. At 5500rpm, you should have the same, if not more pressure than you do at 4000rpm.

Pic was off but the orig 500 bulldog pan baffle set up was hard core . When merc charges 2k just for a cast pan I like to feel every inch nook and cranny . With the large lines right bypass valves in block orig cooler I've seen them support major boosted hp . Long shot and outside the box but maybe something in the cooler ? You running a sea strainer ? Those tall decks dont like dist seal issues down by the lifter galley area but yea be weary of foaming ,maybe run a t from your sender , and get ready for science .

Not every one has your machine work and assembly workmanship Mild Thunder!
Im still surprised your oil pressure don`t drop a bit as the oil gets hotter/thinnner.