Regular oil changes

[jsta281]

First let me say this is not an argument that anyone deviate from the oil change intervals recommended by Nautique, and perhaps this is directed more at the more modern engines, with that said rhis is more of a question, and that is why is it that oil changes are recommended as frequently as they are? I ask because it seems that at least in the newer boats temps over 170 are pretty rare, most people do not spend their boating time at 6500 rpm, and I don't see any other conditions (ie excessive A/F ratios) that would suggest that the oil is breaking down or becoming more saturated with particulates then in a regular vehicle application.

So what is it about boating that requires such frequent changing of the oil?

[scottb7]

I was thinking of extending past the 50 hour suggested interval. I don't where it is but somewhere on this site is the data which turned me back into a believer at the 50 hour mark. I think they proved it to me and I am pretty picky about the data.

That being said I don't buy too expensive of filters, and I go with $13 gallon rotella t. So at $20 an oil change it is pretty cheap. And I have it down to about 20 minutes. Loosen the filter, slide plastic bag over the filter unscrew. No mess, done, new one on. Attach hand drain pump to remote drain plug, pump into gallon size windshield washer or other container, no mess done. Refill.

The data is on the site somewhere...Maybe someone will point you to it.

[core-rider]

If you're trying to justify this by comparing to a car it's not even close to the same. Because of the transmission under normal driving your car engine may only see 2000-2500 RPM and even then that is only before up shifting to another gear. Cruising around more around 1000-1500.

Your boat on the other hand will see higher RPMs and sustained higher RPMs probably around 3000-4000, which will create more stress on your oil. 50 hours doesn't seem like much but in that time the oil is put through a lot.

Even if you're paying someone to service it, $50-100 is cheap insurance IMHO compared to the potential engine damage you could cause costing much more in the long run.


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[jsta281]

If you're trying to justify this by comparing to a car it's not even close to the same. Because of the transmission under normal driving your car engine may only see 2000-2500 RPM and even then that is only before up shifting to another gear. Cruising around more around 1000-1500.

Your boat on the other hand will see higher RPMs and sustained higher RPMs probably around 3000-4000, which will create more stress on your oil. 50 hours doesn't seem like much but in that time the oil is put through a lot.

Even if you're paying someone to service it, $50-100 is cheap insurance IMHO compared to the potential engine damage you could cause costing much more in the long run.


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Ya I am not really complaining or even suggesting it is "overkill" and even if it is I will still do it (I did it in my race car knowing it was overkill). However, It's hard for me to believe that even with a lot more load on average then a car it would be "dangerous" to go farther between changes. Maybe the question is what is 50 hrs equivilant to in miles? I just see clean air, good A/F and low temps as being good for long oil life. Just curious if there is some specific reason, something unique to boating that requires it.

[DanielC]

One thing unique to a boat is the cooling stops when you shut off the engine. It kind of does, in a car, but even with a car engine shut down, there is probably some convection flow going on between the engine and radiator, in the cooling system. Hot air in the engine compartment can also flow out from cracks in the hood, grill opening, and under the car.

A boat engine is in a closed box. Almost no air flows into, or out of the motor box, with the engine shut off. Same thing with cooling water. If the engine is not turning, the raw water pump is not turning, and any water circulating by convection does not go throught a radiator. Long story short, a boat engine soaks in it own heat. This cooks the oil. The higher the oil temp, the quicker it breaks down.

Another reason to change the oil regularly is as the engine is running, the oil gets contaminated by combustion byproducts. Every engine uses oil. Some engine use oil quicker than the comtaminates build up, that engine apparently uses oil. Other engines may not use oil as quick as other stuff gets in to the oil, and that engine will appear to not use oil, but rest assured, oil is being used up, and being replaced by something not as good at lubricating an engine.

By the way, I have bought made in the USA, Motorcraft FL1-A oil filters at Walmart, for less than $4.00 each.

[DanielC]

If you let the oil drain overnight, you get more dirty oil out of the engine. You may have to put more oil in, but the oil will stay clean longer. Opening the engine hatch, when you stop the engine, will also allow some heat to escape, and the oil will not heat up as much, and that will allow the to remain "cleaner" longer.

[nyryan2001]

Jsta- Indmar has proven research regular motor oil starts to break down as early as 30hrs when ran hard. 30hrs proven. There is nothing to dispute with what they showed. RPMs on boat V8s are at least x 2 what you see in your truck.

knowing this is a fact, I run full synthetics changed every 50hrs.

perhaps someone can post up the link.

[Nautiquehunter]

I average 200+ hours a year that's 5 oil changes . I use Mobil 1 15w505 qts for $24.00 at wall mart. For filters I go to eBay Motors I buy the K&N at about 4-5 dollars but all brands are available I buy them in volume 6-10 at a time since I change so often and all three on my inboards use the same filter. Make sure you are getting free shipping before you buy or it will not be a good deal.
I start the oil change the night before and let it drain over night . I do go with the 50 hour changes even though I think its overkill especially since I use Synthetic oil.

[jonsquatch]

I haven't seen the K&N for that in the size I need (HP-3001) closer to 13 and the Royal Purple 30-8A is 12 where the Motorcraft FL1A is just under 5. However I get the specified original equipment PCM R077001 for just under 9 so I figure why not just use that one? It seems pretty well made and while I don't know who makes it I haven't seen anyone complain about it.

[dfoster]

If you really want to check on your oil, you should do a set of oil tests. How you use your boat, the oil that you select, and what has happened to it in the past make your engine unique.

Go to someone like Blackstone Labs, and get at least two tests at the 50 hour change mark. That will give you a baseline. Then you can stretch it out if you really want and see what the difference is. This will also help you get a baseline for your engine and they will tell you when all of a sudden some metal level is increasing and it shows cam wear or coolant leakage. If you are going to stretch out your oil change intervals, that is the only way I would do it and feel confident that I am getting the data needed.

I would guess you could easily stretch out the 50 hour mark with good synthetics and by treating your engine nice... but it really is just a guess without data.