I've asked about everything for my '68 SS, so here is a boat question. My MasterCraft tournament water ski boat has an LT-1 (factory option). In boat form with a NorthStar ignition, it is rated at 328 hp. It is really nice to have EFI in a boat, it's as smooth as a big electric motor.

I have run Mobil 1 10-30 for over 500 hrs, but the manufacturer is saying the engine really wants a conventional 20-50. In a boat, it isn't uncommon to run wide open for extended periods, making the engine see all 328 HP. A car never sees a duty cycle like that. But with 20-50 in it, it runs 60 psi at idle, and over 80 PSI at WOT. I think part of that high oil pressure is because the engine runs about 170 degrees max, and the oil doesn't thin much.

Anyone think this is too high a pressure for a modern, precision manufactured engine?

I just got back from the lake today and hitched a ride from a fellow that had a Dovis (spelling not right?). Anyways it had two BBC 502's though he just had one running. Now I did notice the oil pressure was high on his boat as well as the water temps being low compared to the street driven beasts. I guess always having a fresh supply of water really allows you to keep 'em cool. I don't think it would be much of a problem. Hell, I would rather have high oil pressure than low oil pressure. Just keep an eye on those gaskets though.

gibbons, all I can think of to justify using the heavy oil, is that the operating temp of the marine motors is lower than ideal for the best wear, i.e., you've seen those charts giving better engine wear at higher op temps ( to a point).

So, yeah, for a "land" mill running at an ideal 200, its too heavy ( just swapped my 20-50 out - too much pressure), but maybe for those lower temps.

??? Guessing. Hell, I'd run 10-30 Mobil 1 anyway.



------------------
Gene #62gold/ACES
67 SS396/(427L88) (http://www.chevelles.com/showroom/chaas00.jpg)

Try this stuff,
http://www.amsoil.com/products/tro.html

Mike
www.synthetic-oil.com (http://www.synthetic-oil.com)


[This message has been edited by elcamino (edited 08-20-2000).]

I'd use the Mobil 1, it has proven itself time and time again to be superior to conventional oil. The marine duty cylcle is just another reason to use it. High viscosity conventional oils are like tunnel rams and straight axle front ends...we know better now.