Can a 5W-40 Synthetic handle HARD Marine Use?

[Ryan00TJ]

http://theoildrop.server101.com/ubb/ultimatebb.php?ubb=get_topic;f=3;t=000853#000000

Above is the link for my last UOA on my boat. Undoubtedly there is gonna be some amount of fuel dilution in a hard run rich jetted Marine SBC. There's really no way of getting around it. The oil sheared to a 20W and wear was worse than I expected. Last summer I ran 7.25qts straight Schaeffer 15w40 blend and it ran better than ever. I forgot to grab a sample upon draining it for a UOA. This spring I was out of 15w40 and bought Rotella T 5W-40 Synthetic. I've ran it once so far for about 4 hours yesterday and it ran great. I'm just wondering if the 5W-40 can handle the abuse, fuel dilution and maybe 60-75 hour drain intervals. Opinions?

 

[nickmckinney]

I looked at that link, next time the motor is gone through check the rod bearings for visible copper where the rod end is. Are you getting black "pepper" specs on the plugs? Might have some pre-ignition (high copper and lead). Can you get LL100 Avgas? Thats what the big boys here are running in the boats, smells good, and costs only $2.99 a gallon. You have to jet up about 5% richer or so as the specific gravity is less, but man its a poor man's race gas down here, effective octane a bit over 100 and leaded just right to to save that exhaust valve.

Oh yeah, the oil question, definately use either 5W40 or 15W40 and the super deep filter for the mid 70's truck if you can fit it. IMHO - I would use the 15W40 and change it twice as often, get a Mityvac 7000 suction pump to suck the pan dry easily if you don't already have one. You have a flat bottom oil pan on this motor? How much oil does this thing hold?

On another note - I just pulled apart a nitrous 460 that ovaled the rod big ends by 0.003", frickin amazing the bearings didn't spin!

 

[Pablo]

I really would be tempted to keep it at 50 hrs, and then do an analysis with the Rotella.

 

[Geoff]

Good question. I like Rotella Syn and have thought about using it in our boat too, but have always used Mobil1 15w-50.

Mercury Marine would void your warranty using a multi-vis 30 weight. They prefer straight 40 or their 25w-40 blend. I think probably the HDEO oils can take it. I would do a UOA at 50 hrs. Go with Amsoil's 15w40 if Rotella doesn't work out.

Volva makes a straight 30 synthetic that is recommended for their GM based engines. It could be an option if you can find it.

Can't wait to see the results!

 

[454MAG]

Ryan, I have had great luck running M1 15-50 in my SBC and BBC powered boats. I put about 400 hard hours on a built SBC w m1 15-50 in a 20 ft formula. This motor never saw less than 4200 rpm cruising and was usually 4800-5200. It was a built bowtie block, forged crank, balanced ,etc. The 15-50 holds its viscosity very well when hot. I still had 15psi oil press at idle after a 1 hour run just under the rev limiter with the oil temp in the 290 deg range. I sold the boat still running strong. I have put over 300 hrs on my 454 magnum in a 242 formula which is a heavy boat. I cruise btwn 4200 and 4800 rpms spinning a 23p Mirage. After 40 hrs the oil is still clean looking. Any way I would not run a dino in a boat over 20 hrs. good luck

Ted

 

[Ryan00TJ]

Thanks guys for your help. With my large oil cooler the oil never really gets too hot, over 210 so the oil pressure should stay nice and high. I think if the oil starts to shear the oil pressure will begin to drop at WOT and hot idle so I will keep a close eye on the OP gauge. I'm gonna dump the Rotella T Syn at 50 hrs and pull a UOA.

nick, So far after 3 yrs no signs of preignition runing Exxon 93 octane and 89 octane. My local marina only carries 89 so if I need 93 I have to pull the boat and head into town. I wish 100AV gas was available here. There is a 105 or so octane available but it's like $4.50 a gallon and I can't pull that on a college budget. I'm running a Mororso 7qt Deep sump pan and Melling high flow oil pump, Wix 51773 oil filter which holds 1qt itself. I've got a Mityvac so it's easy to pull a sample or change the oil.

454Mag, Sounds like you really put that 20' Formula threw the paces!

Mobil 1 EP 15W-50 sounds like a good choice to consider for next summer.

I wish I would have remembered to pull an UOA of the Schaeffer's 15w40. I ran it close to 60 hours, and it looked very good and held excellent oil pressure at WOT @ idle at the end of the season. Ohhh well.

 

[Ryan00TJ]

1FMF, I would require some type of compensation$
for getting your boat ready. My own about kicked my *** !

 

[1 FMF]

since you got your boat in already, why don't you come up here and clean mine and fix my starter so I can get mine in.

I have fresh mobil 15-50 in the engine now, from winterizing last fall, and will run that for maybe 20 hours and change midseason to probably delvac 5w40 (truck/suv) since it's now available. Search the uoa's for my member #, I have a few uoa's on my 3.0L. It has a fuel dilution problem, and I ski with the boat so it's almost always 3500-4200 all the time. I guess that can be considered severe use. Will have to wait though till end of summer for the uoa on the 5w-40 though.