synthetic oil

Anybody out there use synthetic oil? I heard it doesn't work well in marine engines, because it does not cling to things. Your boat is not used as much as an auto, so you will have more dry starts. Any thoughts?? What brand and weight??

I have a 257 Carrera Cat with a blown aluminum Donovan and i have always used Red Line 40 weight synthetic oil.In my opinion its the best oil.I also use one bottle of Prolong engine treatment when i do an oil change.Prolong sticks to all the metal parts when sitting for long periods.When i do fire it up after sitting i always pull the kill switch until i see oil pressure.Hope that helps.

I own a StingRay 230SX 502MAG, and I use a Synthetic Blend, sort of a compromise. I also throw in a quart of PTFE additive to ensure good coating during shutdown time. I like AAEN's idea about the kill switch after prolong downtime. That's what is neat about this forum sight, you continue to learn things...

The only blend i've seen is Valvoline, Castol, or Pennzoil. I have a 5.8 liter ford that recommends sae 30, sae 40 or 20-40, 20-50. What weight or brand is good? Where do you find the PTFE??
[This message has been edited by moomba (edited November 28, 2000).]

Your weight would depend on the operating environment. Mine is always spring-fall temps so straight 40W is the way IAW most owners manuals. If straight 40W in not available then 20-40W is an acceptable alternative again according to most owners manuals. There's been debate about the effectiveness of Synthetics in marine applications and that's mostly warranty generated concern. The fear is one would get a hold of a cheap generic brand oil with certain impurities and cause damage, hence the warranty concern. Stick with quality name brand (i.e. spend the xtra buck) like the ones you mentioned, I use Castrol, and you will be fine. Oh, by the way. I'm a stickler. I change oil in my 502MAG every 25 hours. That will help as well. PTFE is the active ingredient in SLICK-50. There are now numerous brands containing this for a reasonable price...
[This message has been edited by StingRay (edited November 30, 2000).]

I too am a believer in syn. oils. I have talked with engine builder Gary Grimes in Atlanta and he reccomends syn oils. His biggest pitch was changeing oil frequently. I have a 540 ci @ 680 hp. Gary told me to change every 25 hrs if running hard and 35 if not. This may sound frequent and cost is high (I have a 14 qt oil pan) but how many hours do you put on a boat in a year. I consider my boating to be high for my location (SC) but I only put 150 hrs a season on my boat. To me this is cheap insurance for what the cost of a motor is to replace or rebuild. I have done some reading on additives. I have a gallon of prolong in my garage sitting. Have you ever seen the sluge build up when heating some of these additives? Not a pretty site! I reccomend: Save your money on the additives and change your oil and filter more often. The best set up is an oil prime system. This set-up will pump oil through your motor with out turning the engine over. $250 The least you can do if you have a kill switch is turn the motor over until you see oil pressure. The bad thing is you are still moving dry parts until the oil gets to them. The motor is turning more freely with the kill switch disengaged.

I talked to a sales/engineer?? at a oil refinery about this and he said that there is much more load on a boat motor than a car. When you push a boat hull thru (not over) the water, it is like pulling a trailer with no wheels on land with your truck. When you back off the acelerator, it stops very fast. That is an indication that there is a huge load. He said a 10-30 synthetic oil is made from 10 weight oil , then adding polymers to it to thicken it up. When the oil breaks down due to the load, you are left with a 10 weight. He recommended straight weights. You can not find a straight weight synthetic oil.
[This message has been edited by moomba (edited December 15, 2000).]
[This message has been edited by moomba (edited December 15, 2000).]
[This message has been edited by moomba (edited December 15, 2000).]

I've used Mobil 1 w/Prolong for a while in my cars. When I got the boat, I started looking into oils a little more since I run hard keeping up with the big blocks and boats stress the motors way more anyway.
Now I'm using Royal Purple Racing 41 which is a straight 40 wt. and their gear oil in the outdrive. Can't be happier and after running it a while, I picked up another mph. Our '92 Checkmate Persuader 219, 350 Mag had 159 hrs. on it when we got it in June, '99 and has 355 hrs now so it can't be attributed to break-in. Oil is clean and pressure runs 60 psi. They also make SAE weighted oils, grease, stc. Look at their graph comparing the Mobil 1/Prolong combo to theirs. If it's to be believed, wow.
http://www.royalpurple.com/
I liked the kill switch tip also. Thanks Carrera Cat.
Scott, "Black Beauty" http://www.CriminalElement.com