best oil to use
 

I know this thread has probably been hashed out multiple times.
509 Mag MPI with a vortec.

I currently am running the mobile 1 15w50. Is this just fine or should I be using something like VR1 racing oil with more ZDDP?
Also thoughts on straight 50 weight for summer in florida.

E

Oil of choice here at OSO is:
Mobil 1 15-W50
and
Valvoline VR1 20W50

So, you have that going for you and really no fights over oil here in say last 5-8yrs or more ?

Amsoil Racing 15w-50 is also a good choice.

thanks for the replies...seems i'm already using good oil.

Diamond performance-I was curious about amsoil. I run there marine gear lube in my bravo.

E

I run straight Slick 50 with a ZMax/Lucas oil treatment stack. Top off with some Motor Honey as needed. :bananalove:

I know a guy that was running 5W30 in his warmed over 500 EFI's because "that's what the builder told me to run". You can't make this stuff up. And no, the builder didn't tell him to run 5W30. He couldn't find 20W50 on the shelf of the brand he was told to use so he just went with 5W30.

I've been running straight HD 40W in Texas for years with no issues. Seems to help keep oil press up when oil gets hot (i.e. 220+ degs)
As for the brand to use, everyone has their own opinion. I personally have never seen an eng fail solely due to wrong brand of oil. IMHO, once past break-in, just pick your favorite flavor and stick with it.

IMO the most important thing to get right first is the correct grade (weight) for the climate you operate in. As an example it pi**es me off no end to see that the dealer/service shop for my pop's car uses 5-30w coz they buy it cheapo in 100 gallon drums when the owners manual clearly calls for 20-50w in my climate .

I thought Griff said NO MORE OIL threads..........:band::party-smiley-048::party-smiley-048::funnypost:

I thought it was the guy from Iran ? :)

They maybe toast soon, glad the Pres didnt reach for the button

Was running Castrol 20W50 until a fellow OSO guy recommended Brad Penn straight 50 (never start motor if I need a jacket). It is different, the 20W50 shows more psi then the straight 50 at idle and higher rpm.

You need to read the report from Mercury after they did a tear down on Teagues motors after a season of racing. No measurable wear after a full racing season running Amsoil.

Conventional Valvoline VR1 20W50.

Used it for years.

I switched to Mobil 1 15-50 & Mobil 1 Filters & I dont have the fluctuations with pressures & temps like I had with others...

Alot of guys assume they need this or that based on bearing clearance. Oh, its a big block, well than it must need a straight 50. IMO, it has more to do with the temperatures youre operating in. I dont think ANYONE needs an engine oil that has 220 centistokes at 100* of oil temp. Of course theres the argument for viscosity modifiers shearing, and breaking down, etc.

Lets say you run 210* of oil temp running hard. Maybe the 15w50,20w50, 25w50 might be fine. Lets say your buddy only runs 150* oil temp in his engine. that 50 grade might be too viscous of an oil for him. a 40wt might be better. Then theres the guy who maybe runs 250* oil temp. He may want to run a 60wt.

Interestingly, the Amsoil straight 60 synthetic, is actually thinner cold, than a straight 50wt , and not much thicker than a 20w50 VR1. So one might say, that guy running straight 60 is a moron, and he's pumping syrup thru his engine, but that would be a bar room assumption.

Could you explain this table
Thanks

Just a generic comparison of viscosities among a few oils and grades. Higher the number, the more viscous the oil is. You can see that at operating temp, the viscosities arent drastically different. However, at 100* F, it varies a ton. Big difference between straight 50 and 15w50 at 100*, not so much at 210*

Viscosity = the resistance to flow, the reason the multi viscosity oils were developed, I ran straight 50 in a drag car but would not in a boat

I think when we are talking bearing clearance vs oil weights, it assumes we are all running the same oil temps. If we feel say, 20 centistokes id fine at 212*, 6000rpm balls out, why do we need 200 centistokes when idling out of the harbor ?

That chart pretty much sums up my thoughts. Even if you had large clearances, you may consider a 40wt oil if your oil runs cold, or, maybe a 60wt if it runs hot

And more cushion for the pushin :drool1:

Has anyone used?

Driven Racing Oil MR50 is high performance marine oil with the extra that your engine needs. MR50 performance motor oil is more than extra anti-wear protection--it's a defense against moisture! Driven Racing Oil motor oil blends an advanced synthetic formula with a high zinc content, plus rust and corrosion inhibitors, to deliver the right protection for your high-output marine engine for both boating season and winter storage. Protect aggressive cam profiles, guard against rust, and defend against ethanol blended fuel with the right oil--Driven Racing Oil MR50 marine high performance oil.

So larger clearances equals viscous oil, adds up. So now what are typical merc clearances?

A bit off topic in regards to oil grades and brands, but I took note of the oil pressure on the 485hp 6.4L in my Challenger. 0w40 Pennzoil synthetic, all readings taken at idle in gear.

60*=55psi
100*=53psi
125*=48psi
150*=42psi
175*=34psi
200*=29psi

I see alot of guys complaining of low oil pressure at idle after a run in the boats. usually they want to go to a heavier weight oil to solve the problem. While it may help, often its because they are simply getting the oil too hot. You take a big block thats custom built, chances are its gonna have fairly loose clearances. When that oil gets hot, as in 220, 230, 240* plus, even a 50wt oil is gonna be pretty dam thin. Thin oil, loose clearances, its gonna be bleeding out internally at idle from the mains. You knock that oil temp down from 230* to say, 180, theres a good chance you'll find 10 or more psi at idle after a hard run.

Agree, changed my oil cooler out 3 times before I got it barely down below 200* (going in) cruising

Been running Amsoil 15w50 racing oil for 9 years and my oil cooler is small for my hp and when running wide open I'm running oil temps around 280. Talked to the Amsoil tech and they said it's not a problem, and based on how clean the oil comes out at the end of the season, I have to agree. When I drop to an idle after a hard run pressure drops to 15-20psi. By the time I get from the beginning of the no wake zone to the mouth of the river (about 200 yards) my oil temps are below 200 and the pressure is back to 40-50psi. My oil pressure is super stable, I boat in very cold water from 35 degrees up to 80 and my oil pressure doesn't vary much from cold start to 200. Best part is when I'm out on the lake in mid to late October when it's 40-50 degrees out it doesn't start any harder than when it's 90 out. I did a partial tear down a while back to do an inspection and everything looked new after a couple hundred hours of running.

recommended motor oil
 

I use the manual, the recommended oil weight for merc is a 40 weight, multi viscosity or straight 40 weight. The chart also shows, your good for a straight weight in hotter weather. The ambient temp in AZ, is 110 on average.
Vr1 40 it is.

https://cimg8.ibsrv.net/gimg/www.off...4dea14724b.png

Well thank you ThisIsLivin,
i've been looking a whole lot for someone that has been running higher oil temps with success.

I believe in running warmer than "normal" just to keep the oil drier from moisture..... and also to get rid of the remote oil adaptor, 3 hoses, remote filter mount, and of course the oil cooler. I want things simple and dependable, all that stuff gone. Less weight, more room, and less leak potential, more oil flow probably.

But my temps when i temporarily bypassed the cooler last summer ran 280 at cruising just under WOT, 4500 or so for a few minutes in 90 degree weather here on the Gulf Coast. So was nervious to do this but apparently you've had good success. I feel better now trying it. Haha.

I've got twin 1998 502MPI's on a 32ft Sutphen modified only with advanced upper end timing to 36 degrees and Eddie Marine exhaust. These two things added 6-7 mph.

By the way i did just talk to a mechanic that took apart an old 305 on a cruiser that ran without an oil cooler for years probably at 3/4 or more throttle and 275plus oil temps. said the cleanest motor he's taken apart.