1986 454 Crusaders, Synthetic?

[Phishin]

A few months ago, my brother purchased a 1986 Tiara 3600 Open. It's got 980 hours on each motor.

From what I've been told by the previous 2 owners (we are now the third owners), she's been on a steady diet of Mercruiser 25w40. I don't see much tarnish/gunk at all inside the filler caps. And since the oil was changed every fall, each OCI (27 oil changes on this boat) typically only had 30 hours on it...so I wouldn't expect much dirt either.

The Mercruiser 25w-40 oil has 1600ppm zinc from what I can find. But LOW detergency, and low boron and zero moly. Pretty bland stuff.

I'm responsible for maintaining this boat, and since finding BITOG, I'm having a hard time putting this Mercruiser oil back in her this fall.

Of course, it makes better sense to run a Dino SL/SM rated HDEO like Rotella, Delo, etc. But would you recommend a synthetic to clean up the internals a bit and keep this boat running at tip-top shape? Amsoil makes a decent Marine oil. What about running something like Pennzoil Ultra 5w40? Or even Red Line? I'm a little leary about running an ester based oil in a marine environment though.

Stick with the HDEO dino oil or run a synthetic? My brother knows nothing about engines and but runs synthetic in everything he owns. The price of the oil is of zero consideration for him. So, if price is to be ignored, what would you run?

 

[Rand]

keep using the marine oil. Boat usage is nothing like car usage.

but main reason!
you wont be blamed for any failures.

 

[bullwinkle]

I run Delvac 1300 15W40 in my Mercruiser 350 Magnum in my '88 25 ft. Chaparral, seems to work as well or better than the big $$$ Merc oil.

 

[Doog]

I have used the 25w40 for over 25 years. OCI is 40-50 hours. Never a hiccup. Never an oil burner. Forget the synthetic for any engine pre-1994. You will do fine with the 25w40 but if you insist on changing then I would try Brad Penn 20w50 racing or Valvoline VR1 20w50. BTW I was always able to get the 25w40 for under $5/qt at WalMart.

 

[Doog]

Originally Posted By: Phishin

From what I've been told by the previous 2 owners (we are now the third owners), she's been on a steady diet of Mercruiser 25w40. I don't see much tarnish/gunk at all inside the filler caps. And since the oil was changed every fall, each OCI (27 oil changes on this boat) typically only had 30 hours on it...so I wouldn't expect much dirt either.


So? why change?

 

[Phishin]

Originally Posted By: Doog

So? why change?


Because I want to run the best oil in her. Just because this Mercruiser oil has done well and has always been used, doesn't mean it's the best oil for the job.

I was just looking for opinions. See what others think. I doubt I keep the Mercruiser oil boat though.

 

[danthaman1980]

You want a NMMA FC-W certified oil in those engines. I'd use Quicksilver 25W40 Synthetic Blend - it might be the best oil in that application (not the full synthetic - it has lower levels of phos and zinc to allow for use with catalytic converters)

Diesel or automotive oil will work, but marine oil is purpose-built for marine engines.

 

[Phishin]

Originally Posted By: danthaman1980
You want a NMMA FC-W certified oil in those engines.


From what I've read, the only qualification that is required for NMMA FC-W is a corrosion test that any oil would pass. Probably even olive oil and Baby Oil.

I under the load these engine put on the oil is not like a car/truck. These engines also run cooler than a car/truck. So, I understand that I need a sheer resistant oil. No problem there.

The last thing I want to run is Quicksilver or MerCruiser oil. I just can't pull myself to do it. I'm sure there is nothing wrong with these oils, but there is something about re-labelled oil that is a huge turn off. I'd rather run a Pennzoil, Mobil 1, Valvoline, etc. brand oil in anything I own.

I like the idea of VR1 20w50. Not a bad selection.

A lot of people run straight 30 or 40 weight oils in these engines. So, what would be wrong with running M1 0w40 in these things, since it's gonna shear down to 0w-30 anyways....

 

[Doog]

Originally Posted By: Phishin
Originally Posted By: danthaman1980
You want a NMMA FC-W certified oil in those engines.


From what I've read, the only qualification that is required for NMMA FC-W is a corrosion test that any oil would pass. Probably even olive oil and Baby Oil.


Marine oils cling onto the surfaces all winter while that boat sits in the yard. Automotive or a 0wXX will not. If you want a name brand then get Pennzoil Marine 40w. Remember your start up temps are over 50F anyway. Plus you don't start a boat and then hit the throttle when cold as well. 99% of people let them sit for 5 minutes before take off to reduce chance of a stall in the marina.

 

[Doog]

Originally Posted By: Phishin

The last thing I want to run is Quicksilver or MerCruiser oil. I just can't pull myself to do it. I'm sure there is nothing wrong with these oils, but there is something about re-labelled oil that is a huge turn off.

Mercruiser Quicksilver oil is not "re-labeled" they are private labeled which is different. Those Crusader engines are private labeled GM big blocks sold to Crusader Marine. Same as Mercury Marine. Mercury specs Quicksilver oil (usually by Citgo or Mobil) to their spec. So, you are not buying "Supertech" like at Walmart.

 

[Doog]

Originally Posted By: Phishin
Originally Posted By: Doog

So? why change?


Because I want to run the best oil in her. Just because this Mercruiser oil has done well and has always been used, doesn't mean it's the best oil for the job.

I was just looking for opinions. See what others think. I doubt I keep the Mercruiser oil boat though.


I could line up 10 boat mechanics with over 300 years of experience who would tell you to continue with it.

 

[hemitom]

I used to run the quicksiver 25w40 never an issue, i also ran 15w40 with no problems .In Canada at the time i think it was blened by shell, if i remember correctly it was blended with little or no VI improvers.

 

[hattaresguy]

Any 15w40 will be fine too.

Marine engines don't wear out from oil, so whatever you use doesn't really matter.

 

[RTexasF]

Considering the age of those engines and the hours on them I think you could end up dealing with excessive oil consumption going with a full synthetic.....at least for the first few changes. Fiddling with what has worked well since 1986 is pointless to my way of thinking, leave well enough alone and quit trying to reinvent the wheel.

 

[Silverado12]

In your situation, I would continue using Merc oil, since it's served well over the years. I personally use Delo 15W-40 in my 20' Chaparral 4.3.

 

[Phishin]

Ok, Ok, Ok. I'll leave the lying dog alone.

I guess the Mercruiser oil might go back in her then.

So far this year, the boat's been ran for 3 hours. 3-5k RPM's the entire time, except for warming her up in the marina for a few minutes....and neither engine has used a drop of oil.

 

[Tuffy1760]

I'd go with a marine grade, maybe pennzoil, RP or amz...

 

[paulswagelock]

I have posted a few UOA results here. The Mercruiser 25w40 has sheered to a 20 wt in every analysis I ran, in multiple boats, after 50 hrs of use. These are well maintained mid 2000 year v8 engines. Now, the wear metals were not terrible even though it sheered, but I have seen the same or better results with Rotella and Delo 15w40 in the same boats. Half the cost, similar results. Simple choice for me.

 

[hattaresguy]

Those are good motors btw, they are good at burning gas. We used to run my grandfathers Chris Craft 315 Commander across LIS for lunch at just about the stops which was about 40GPHish.

Used to take about 70 gallons to get lunch and back, I love doing lunch runs!

What does the 36 burn at WOT?

How are the risers? That's what kills marine motors, not oil.

 

[terminaldegree]

I'd keep using what it has been using, or maybe straight 30 or 15w-40 Dino. I would not switch to syn, but that's just my opinion. On a boat this age and size you will have a lot of other maintenance and repair issues that will be far more important and expensive than oil selection. Are the carbs working well? Fuel filters and water separators changed? Cooling water impellers changed annually? Any leaks from anything mechanical/stuffing box? Load test batteries? Shafts in good alignment? Seawater strainers cleaned? etc, etc.

We joke in our family that we breathe a sigh of relief every year the compressors on the refrigerators and a/c fire up after the winter layup... whew, dodged a big bill for another year!