mcrsr

is there any problem w/ running a hi volume pump w/ the stock 6 quart pan on a mark4 mercruiser bbc?? originally i was running a stock pump and cooler, and after 3 minutes at wot oil pressure would start to drop, so i pulled the engine, installed a much bigger oil cooler and a hi volume pump but haven't run the boat yet-has anyone done this??

fbh-velocity

If you have a standard 330 it has 8 qt oil pan. You can run a high volume oil pump but you will push the load on distributor gear and normally there is no need for more than standard pump. If your problem is that the oil is running warm the high vol pump will not solve your problem. What oil are you using? Have you tjek your oil cooler, if it is blocked on waterside you won´t have full cooling capacity

mcrsr

motor was originally 330 hp, i rebuilt the engines using speed pro pistons, comp cams, large oval port heads and performer intakes and spin them 5000, both motors were doing the same thing, oil psi at 5000 would start at 45 and gradually drop to 35 before i backed off, if you cruise at 3500 the oil pres stays at 45 psi, and the oil cooler on the engine is about 3 inches long-it is a combo oil/power steering cooler- i replaced it w/ a marine power cooler that is about 8" long(almost 3x larger), i notice now running the engine on the shop floor that my oil psi is 70- i just am concerned about pumping the pan dry

1BIGJIM

iTrader: (1)

Is that a Pachanga in your picture(aviator)?

fbh-velocity

I dont think you can run the pan dry, make sure your oil level is between the marks on the oilpin. If your oil pressure is fluctuating on reading when you WOT it could be a indicator for low oil in pan.
Many engines has bin build with hi vol oilpump with no problem.

RLW

Am I reading this correctly? A 3" long oil cooler?
What are your oil temps?

MESABALANCING

I think you need to research the problem a bit more the std pump is fine for 99% of the applications out there it seems to me with the cooler you're running your temp is rising excessively get a mech gauge and check the oil temp and if you're going to run the high vol pump make sure you have the adequate amount of oil in the pan after you start the engine and get the cooler ,lines and filter full that's going to be around 8-9 qts depending how long a lines you have optimum oil temp is 220 degrees at wot don't try to get it lower that's were the oil needs to work your temps now should be much higher and the oil press if all the bearings and clearances are good is going to be 55-60 with std vol and 65-80 with a high vol. If you need a good cooler call Fred at Trick Marine he's got the best quality and prices anywhere. Best of luck Laz Mesa

mcrsr

its a 32 pachanga, gps speed is 70, the stock merc cooler assy is about 2.5" in diameter, the length of the cooler between the oil side is about 2.5",same w/ the power steering side, i just purchased the marine power cooler which is 3x the size of the stock cooler, so it should cure the problem,also, i was running castrol 20w50 prior to this, and was wondering if i should switch to 10w40, oil capacity seems to be 6 quarts, i used a primer before i fired it so i know dry capacity(according to the dipstick) to be 6 quarts

1BIGJIM

iTrader: (1)

MCRSR,
You have one engine with a 70MPH GPS?

I have the 22' and am having a hell of a time to breaking 75MPH with a 496 with 500HP.

I spun a bearing on a new reubuild and the machine shop thought I might be running out of oil also. Who knows I changed back to stock pump and stroked the engine and all has been fine.

mcrsr

no, it is twin engine, the boat is fully loaded,w/ a/c, and dive gear,etc, also, the stock speedo is generous by about 7-8 mph,i can almost pin it at 80!!! did you have a 330 and if so what is your oil capacity???? what are you using for a prop?? what outdrive??