Reed Jensen

Dang Dannysixpack... you got me... I didn't know you were running a "ring-ding..ding..ding " two stroke...

MACDAD260

Watch your oil pressure when you bring the motor down to an idle after a hard run. If it stays close to where it is when running at high rpm then you are OK. If it drops to 10psi or less when you bring it down then your temp is too high.

On my mine, the pressure drops to 10-15 psi at idle if the temp gets to about 240 running Mobil-1 15W50. Anything less than that and the pressure stays up. I put on a 3" X 12" oil cooler this year and so far it doesn't get above 235* and the pressure is good when coming down to an idle. Good luck.

DannySixPack

Sounds ideal.

RLW

Andrew,
What are you running for an oil cooler?
I am assuming a crossover instead of a recirculation pump.
Does the crossover have a bypass?
Are you using a T-Stat?
Russ

R Addiction

Stock 502 mag with (Gil exhaust) runs 200-210 normal cruise, then 220-230 when I'm out showin' somebody who's boss!!

OldSchool

I'm running 502's (na) with crossovers, no thermostats. If I keep it around 3500 rpm's, my temps are 220-oil and 130-water. Last weekend we ran real hard for about 30 minutes (4500-5000 rpm's) and the oil got up to 260 and the water temp was about 165. When we let off, the temps went back to normal within 3-4 minutes.

Is that OK/normal?

DannySixPack

Sounds Ideal.

If you were going to run hard consistantly and for many hours (or many 1/2) sessions at a time, i'd look into an oil cooler. 260 is well within 'safe' ranges, especially when it dropped back down in a few minutes.

The trick with oil is you have to get it 'hot enough'. If it never gets above boiling (point of water) you'll never burn off the condesates and acids. If it gets too hot, it will gum up the works (after it cools down). If you put in an oil cooler without thermostats, with the usage you describe, most of the operation time would not go above boiling and that would not be good.

someone earlier described to observe the behaviour of the oil pressure when you go back to idle. This is a good idea as it really shows you when you've warmed up the motor enough for the pressure relief valves to come into play (which is warm enough).

-when the motor is cold, the oil pressures are high.
-when the coolant reaches normal operating temps but you drop to idle and the oil pressure is still on the high side, you still haven't warmed up the motor all the way.
-When the coolant is normal and the oil press drops significantly at idle, the motor is warm.
-When the coolant is normal and the oil press drops dangerously low at idle, it's time to think about better oil or a cooler

just general rules of thumb. If you have an oil temp gauge you don't need to guess. Get the oil to at least 215-220 before you put the boat away, if it goes way too hot too often, put in a cooler (with t-stats).

ActiveFun

Russ,
Hi. The Motor was just rebuilt. The oil pressure is 60 lbs at idle and up to 70lbs running. The oil cooler I have a Merc part # 816482T. Its for the Merc 800's. There is no T-stat and the water temp never budges over 100. The oil sender is on the port side of the block down just above the oil pan. Should the sender be at the top by the filter?? Currently where the oil temp sender usually goes on the oil filter bracket I have a oil pressure switch which is connected to my electric fuel pump. This way, if the pump doesnt sense oil pressure, the motor will shut down. The engine runs perfect. I just cant figure out while the oil temp is reading high. We checked the temp with a laser at the filter and it was the same as the guage, But I only did that at idle when the oil temp was low and never checked the temp with a laser when the guage was reading 240.
Thanks