Low Oil Temps ...
 

Having Issues with oils temps getting up over 200* during normal cruiseing ..... 496 MIV motors with external KE 212* Thermostats and 3x18 HP style merc coolers ... Normal cruise 3000-4000 rpm the temps get up to 170-180 ... I did some testing this past weekend bypassed the cooler on one motor and Temps came up good .... Temps got around 230 and I assume would continue to go up if I had pressed on .. I am having milk issues in the top end but after the test run the oil cleaned right up ...

What are my options ? Should I bypass the water thru the coolers with an adjustable valve or bypass the oil around the coolers ? I have no doubt that if I go WOT for 10 miles things will be fine but the Norm would be a 1 hour cruise to the local watering hole @ 3500-4000 rpm and temps be where they need to be ....m

offthefront
Optimum oil temp for any oil according to SAE is 220 degrees. When I test the engine on my dyno we have a ball valve controling the water supply to the oil cooler to be able to control the temp as we would look for it in the boat or car. I would only worry if the temp climbed over 240-260 with conventional oil we've even run marine racing engines at 280 degrees with synthetic oil for a complete season with no bearing or oil related damage at all. Keiths system is one of the best on the market you may also want to contact them I'm sure you'll get the same reply. Best of luck Sincerely Laz Mesa
www.mesaracingengines.com

Thanks Laz ... I'm thinking the water will be the best to bypass around the cooler.... its just confusing why the Thermostat will not do the job it is designed to do .. maintain a min of 212* ....m

I put an oil thermostat on my motor. Keeps the oil temps right where they should be.

http://www.racerpartswholesale.com/mocal.htm

It's an inexpensive, nicely constructed piece that looks to have good flow charactaristics. Even when it's open, some oil goes through your cooler, but when it heats up and closes, all the oil goes through your cooler with little or no restriction from the thermostat.

Dave ... I have a thermostat ..for some reason not doing what is designed to do ....m

http://www.keitheickert.com/detail~ID~1035.aspx

Try a new sender.

I put new gauges on my boat not long after a motor rebuild. I noticed with the new gauges i didn't get very high oil temperature... the highest I saw was a bit over 200° after a solid 10+ minutes at WOT. So I added a thermostat at the end of the season.

After I put the thermostat on mine, I noticed I still didn't get the temperature coming up to where it should be, even though I was getting a slightly higher temp reading with the thermostat. So I went and got one of those infrared thermometer things for about $20 at harbor freight. Sure enough, the temp at the oil filter was getting up to right where it should be. A new sender fixed the problem. Not sure if the old one was crapped out or just not matched to the new gauges, but a new sender did the trick either way.

Nwe Guages .. new senders ....checked the gauge reading with infarred the other day ....match ......

Hmm. I'm all out of ideas.

Is there a chance your thermostats aren't functioning properly? I don't know how you'd really check that.

Has this always been a problem? Are the motors stock except the oversized oil coolers?

I'm not sure exactly how that thermostat functions, but if the oil coolers are drastically oversized and the thermostat doesn't close off flow to the oil cooler at low temperatures (which is how mine function) maybe enough oil is flowing through the cooler even at low temperatures that it will just naturally prevent the oil from warming up until you run the piss out of it.

I'd say you hit the nail on the head. The other determining factor is oil quantity. Do you have a big oil pan? If you have a large quantity of oil, it stands to reason that it will take longer to heat up. With say a 14 qt. oil pan and an HP6 oil filter, you could have close to 18-20 qts of oil in the whole system. It will take a looooong time to heat up this much oil. However, you will need it to keep the temp managable when you stand on it for extended periods.
I had a similar problem in the past and after talking with Mike at CP Performance, he told that they had switched manufacturers of the thermostat. If you have an older (2 or more years) one, you may want to change the thermostat. They also changed up the design a little on the oil coolers with built in thermostats. They used to leak enough oil past the thermo. that it would never heat up. I don't know if they changed the design of the unit you have, but it may be worth a call to CP and speak with Mike (ext 17). Hope this helps, Eddie.

Eddie thanks for a responce ... these are standard 8 quart merc pans ...the thermostats were new in aug. ..seems they are open all the time ... I have check gauge readings and they are dead on with infarred ... Also the milk went away when when I bypassed the cooler So I think my readings are pretty close ....m

496 MIV's ~550-600HP ..... motors are new builds since oct and still chasing gremlins ... I find it hard to believe both stats are bad ...m

Talked to Mike at CP and he thinks the cooler might be oversized ....hmmmm ...again I would think the Thermosat should bypass the cooler as needed ... He Agreed that maybe ajustable water bypass around the cooler might work ...Sounds like a thermosat to me ......m

Hi Offthefront,

Where are you taking the temp readings; remote filter housings or the pan?

we tapped the blank port on the thermostat ...seen in the pic ..its in direct flow of the oil coming from the block ( thru filter first .. The milkshake on the bottom of the breathers is evidence the oil is too cool ...m

I had the same problem. My cooler was to large, after scratching my head for a week and didn't want to change the cooler to a smaller unit I bought one of these about $45.00 from Summit Racing installed it on the existing cooler and walla it 's been working for 2 years now and no problems. When oil temperature exceeds 180°F the thermostatic valve closes, allowing 95% flow through the oil cooler. At temperatures below 180°F the valve is open, with 90% of the oil bypassing the cooler. The remaining 10% of the oil flows through the cooler, maintaining constant system pressure, preventing air pockets and eliminating cold oil shock. Flows up to 20 gallons per minute (GPM). Rated to 200 p.s.i. Thermostat mounting kits containing four brass fittings, four stainless steel hose clamps and two nylon tie mounts are sold separately. http://www.perma-cool.com/Catalog/Cat_page14.html

that unit keeps the oil below 200* ....it needs to be above 200* .........

Hers one that opens at 200 degrees. If that helps.
http://www.racerpartswholesale.com/d...hermostats.pdf

I Ran the boat today with a water bypass installed around the oil cooler and pretty much no change ... I installed the valve in the bypass line and maybe it need to be in the main line feeding the cooler... However ... Ran at 3200 for about 3-4 miles (after a 10 min idle zone) and both temps come up to about 160 (oil)and then ran 4000 for about 4 miles and temps did come up to 180's... actually the motor without the bypass ran a little warmer on oil temps ... both water and oil ...motor with the water thermostat runs about 150-160 (water) at 4000rpm and the one without runs 140-150(water) ... I guess the bottom line is you need to run it hard to get the oil temps up ... It could be worse and be too hot .... The water line from the pump to the cooler is 1.25 and the bypass is 1". maybe a valve in the 1.25" after the bypass to restrict more flow to the cooler might work better but the whole bypass Idea is an abortion (plumbing wise)...... m

Good Argument for the Rev Limiter (wife) to get the revs up ....:D

Wonder why you temp came up on the first bypass test in the first thred and not on this test? Weird

The first test bypassed the oil around the cooler ...no oil thru the cooler ... Second test bypassed the water around the cooler ....but not totally ..just a shunt around the cooler with 1.25" water line intact ....it was a 1" bypas with a 3/4" gate valve ... Since then I bypassed the other motor with a 1.25" line with a 1.25" ball Valve ....better results but not there yet ... next will be the 1.25" bypass with ball valves in the Bypass AND the water Supply leaving the Oil cooler so I can Throttle back water thru the cooler .... I think that might do it ...m

I see now, OK. That should do it, let us know Thanks K.C,