454 oil temp question
 

just purchased a used boat with twin 454's one engine's oil pressure drops 20 lbs lower than the other engine when in neutral @ 2800 rpm's, installed temp gage at same location as temp senders for alarm and pressure gages, the temperature never gets above 100 deg's even after eng temp get to 140 deg, raw water cooled, the oil filter gets hot about 110 deg, any help would be appreicated

Thanks Tom

Are you sure the gauges are good and the senders match the type of gauge(brand).. If i remember right some gauges, like gaffrig, required the use of a gaffrig sender.

Are you saying you put the temp sender in the oil filter housing and thats where you saw 110 deg?

oil temp
 

the temp probe is installed in the same location as the alarm and pressure gage senders, I took the filter temp with a temp gun, both engines have the same senders and gages
thanks

Don't quote me on this because I'm not sure but shouldn't the oil temp sender be installed in the pan? I doubt that the sender can tell the difference between oil temp and block or metal temp being that close to it? Am I wrong?

You can take readings at the filter housing, but temps are usually higher there than what the sender would read if it were in the pan.

Why are you reving engines to 2800rpms in neutral to start with??????? Free reving is very hard on the engines.

Oil temp should be taken from the pan. The location you have it does not work, nor will the filter location. If you only had 100* oil temp, you would have all kinds of moisture in the oil and it would be milky. Get a point and shoot infrared temp gun and point it at the oil pan.

I don't like to measure oil temp in the pan because it takes the oil cooler out of the equation. For example, lets say the oil in the pan is at 250*. If you have a small oil cooler, then the engine may be seeing oil that is 230*. Now if you have a larger cooler, the engine may be getting oil that is only 190*. You want to know what the engine is seeing for oil temps.

The biggest key is to be sure that you have the oil temp sender in the flow of oil. If it is put in a dead end oil passage, it willnot give a correct reading. In a Gen VI block, the best place is just above the stock oil filter pad. That will put it in the flow of oil just as it enters the engine.
I would install some temp. oil pressure gauges to be sure the pressure readings are correct and then go from there.
Eddie

oil temp
 

thanks for the replies but I still have questions about the temp, this is a 32 ft fishing boat, max speed about 35mph, oil temperature is 115 degs. reading with a temperature gun on the bottom of the oil pan, do I need to bypass the oil cooler to get the temperature up and if so what should the temp. be

these engines are stock, remains with less than 300 hrs, the oil pressure sensor is located above the oil filter adapter area, there are no ports in the distributor or pan area for connections
Thanks for the help
Tom

I would bypass the coolers. That can be done easily and see what you get for temps. I realize the importance of external coolers however in many marine applications especially with stock engines they can be overkill. A lot of the older boats Merc didn't even have coolers. I have 13 plate coolers in my TRS 496's however they are thermo controlled as well as overkill. Running to low of oil temps are hard on an engine. Also free reving is OK to a degree. 2,000 o 2,500 rpm is where your engine runs with the least amount of strain.

I really cannot understand how you can really have 115* oil temps. That is so extremely low, thats its almost unheard of. How cold is the water in the lake??????

If you're looking for help in sizing the cooler give us a call. with some conversation and data gathering we may be able to size your cooler for you. I'm with Griff. I don't understand how you're getting 115 oil temps so I'm looking for a little more information. When you figure a standard auto engine is 160-190, it doesn't make sense. And oil that cool is simply bad for your engine. It's like it's always starting.


Russ
www.mrcool.us

Get Russ,
Can you email me a price on a 13 plate cooler. I need another one. I bought one from you earlier this past summer. The other one I had I am a little leary of.
This is for a TRS bell housing. I can't remember off hand if it's port or starboard?
[email protected]
Thanks,
John

Are you sure the temp gun is not set to Celcius???????

I didn't think of that. That would make perfect sense. Good call.

John: Quote is in your box. Gave you 10% off (deal for Feb OSO pals). They're in stock.

Russ :-)

Thanks,
I'll take care of it this week.
much appreciated.

John

that 100 deg oil temp is wrong...something not right there..unless you are only running for 10 mins...

Grif hit it. 115C is 239F. Just needs to press the button on the unit to convert to F.