HammerDown
07-18-2002, 07:13 PM
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WHAT ABOUT SYNTHETIC OIL?
Question: I would like to know if it is okay to run synthetic oil in a boat engine? I have read many different answers to this question, but would appreciate your professional opinion. I am running a stock 502 Magnum MPI and have always used Mercury's oil in it. I use Valvoline SynPower synthetic in my tow vehicle, but don't want to put synthetic oil in my boat without knowing if it is okay. If it is okay, what brand do you recommend?
Answer: This is a widely debated topic. Of course, the synthetic oil manufacturers would want you to believe that their products are going to increase your engine life. I have used a few synthetic oils with pretty good success, including Red Line, Mobil 1, and Amsoil to name a few.
In racing applications, I have done testing by using two different types of oil in each engine in the same boat. After the race, when the engine was disassembled, there was evidence that the synthetic oil was slightly superior in the competition environment. The same results have not been observed in the recreational marine engines, though.
More recently, I have noticed that engines with roller lifters used in the pleasure-boat environment have exhibited undesirable wear patterns when synthetic oil is used. Specifically, because the oil is more "slippery," it appears that the rollers are sliding on the cam instead of rolling. This results in flat spots on the rollers and increased wear on the cam lobe. This problem only seems to present itself with lower valve-spring tension applications typically used with hydraulic roller cams. In race applications, with solid roller setups where 250 or more pounds of spring pressure exists when the valve is on the seat, there seems to be enough pressure to keep the roller on the lifter rolling on the cam instead of sliding.
Depending on your climate and the water temperature you typically operate your boat in, the viscosity of your oil should be selected accordingly. I believe that a straight grade SAE 40 oil is the most suitable for the majority of the performance marine engines. SAE 30 would be better for cooler climates. For extreme performance and supercharged engines, SAE 50 is suggested. Most synthetics are a multi-viscosity oil. Fuel dilution of the oil and contamination as a result of increased moisture in the crankcase seems to affect the multi-viscosity oils faster.
The most important thing is that you change your engine oil regularly and use a good quality oil. I think an oil change every 25 to 50 hours is a good idea. The higher performance your engine is, the more often the oil and filter should be changed. I use Kendall SAE 40 in all the pleasure boats in our Southern California climate, and SAE 50 in the hot rods.
I have found the synthetic oils are always superior in gear boxes, blower gear cases, and stern drives. Red Line's 80-140, and Amsoil's 80-90W, to name a couple, seem to provide extra protection in Bravo drives. If you are a reader that has a Casale V-drive in your boat, put synthetic oil in it. You will be surprised how much cooler it operates.
*The question was asked from a reader of Power Boat Mag.(not me) The answer was given by Mr. Gary Teague. (Teague on Tech)
*I always did like Kendall products...HammerDown
[ July 18, 2002, 08:15 PM: Message edited by: HammerDown ]
WHAT ABOUT SYNTHETIC OIL?
Question: I would like to know if it is okay to run synthetic oil in a boat engine? I have read many different answers to this question, but would appreciate your professional opinion. I am running a stock 502 Magnum MPI and have always used Mercury's oil in it. I use Valvoline SynPower synthetic in my tow vehicle, but don't want to put synthetic oil in my boat without knowing if it is okay. If it is okay, what brand do you recommend?
Answer: This is a widely debated topic. Of course, the synthetic oil manufacturers would want you to believe that their products are going to increase your engine life. I have used a few synthetic oils with pretty good success, including Red Line, Mobil 1, and Amsoil to name a few.
In racing applications, I have done testing by using two different types of oil in each engine in the same boat. After the race, when the engine was disassembled, there was evidence that the synthetic oil was slightly superior in the competition environment. The same results have not been observed in the recreational marine engines, though.
More recently, I have noticed that engines with roller lifters used in the pleasure-boat environment have exhibited undesirable wear patterns when synthetic oil is used. Specifically, because the oil is more "slippery," it appears that the rollers are sliding on the cam instead of rolling. This results in flat spots on the rollers and increased wear on the cam lobe. This problem only seems to present itself with lower valve-spring tension applications typically used with hydraulic roller cams. In race applications, with solid roller setups where 250 or more pounds of spring pressure exists when the valve is on the seat, there seems to be enough pressure to keep the roller on the lifter rolling on the cam instead of sliding.
Depending on your climate and the water temperature you typically operate your boat in, the viscosity of your oil should be selected accordingly. I believe that a straight grade SAE 40 oil is the most suitable for the majority of the performance marine engines. SAE 30 would be better for cooler climates. For extreme performance and supercharged engines, SAE 50 is suggested. Most synthetics are a multi-viscosity oil. Fuel dilution of the oil and contamination as a result of increased moisture in the crankcase seems to affect the multi-viscosity oils faster.
The most important thing is that you change your engine oil regularly and use a good quality oil. I think an oil change every 25 to 50 hours is a good idea. The higher performance your engine is, the more often the oil and filter should be changed. I use Kendall SAE 40 in all the pleasure boats in our Southern California climate, and SAE 50 in the hot rods.
I have found the synthetic oils are always superior in gear boxes, blower gear cases, and stern drives. Red Line's 80-140, and Amsoil's 80-90W, to name a couple, seem to provide extra protection in Bravo drives. If you are a reader that has a Casale V-drive in your boat, put synthetic oil in it. You will be surprised how much cooler it operates.
*The question was asked from a reader of Power Boat Mag.(not me) The answer was given by Mr. Gary Teague. (Teague on Tech)
*I always did like Kendall products...HammerDown
[ July 18, 2002, 08:15 PM: Message edited by: HammerDown ]