Rebel_Heart

Have any of you oil gurus done a test on Neo motor oils? I was specifically considering the P40 conventional oil. Currently using Valvoline 40w.

minxguy

High TBN numbers have nothing to do with storage.

It is a number on a scale that is used to deal with acid neutralization from combustion in diesel engines.

The acid was formed due to the sulfer in the fuel, but due to low sulfer diesel fuel now, this number is not as important as it was 15 years ago.

If your hanging your hat on a TBN number, times have changed.

Ken

apollard

True, TBN has little effect in storage.

But TBN is applicable to gasoline engines, as both sulfuric, nitric and organic acids are formed from combustion gases and water - in any internal combustion engine. It is true that the previous higher sulfer content created more acid, but the issue has not gone away. That is why "extended change" oils have higher TBN to start.

minxguy

I agre the issue has not gone away, but with low sulfer fuels, both gas and diesel, it is much less of an issue.

Besides, when you store you engine, you should have fresh oil in it and there should be almost no contamination in it.

Yes "extended change" oils have a higher TBN, but does anybody really change the oils at the extended interval?

I would guess the majority of the people on ths board would say no.

Ken

Mariah212Z

High TBN is going increase the amount of additive the oil has left to neutralize acids. When your boat is stored the oil sits on the engines bearings and this is were excessive acids can take a toll on the bearings surfaces. The high TBN is insurance that over time the additive content level is still high enough for proper acid/soot control.

Acid neutralization also takes place in gasoline engines.

Amsoil 15W40 Marine Diesel has a high TBN number of 12 which is even higher than most synthetic oils which are usually around 9. This high TBN gives this oil a higher drain interval. This gives the oil a longer acid fight control within the motor.

I don't were hats.

minxguy

I guess you didn't read my last post.

Ken

Hematite

That's exactly what I was thinking!!!

sleek1

Anyone try the Amsoil Z-Rod 20-50 yet? Advertised for long lay ups with more antioxidants and corrosion inhibitors. Not sure if it's a class IV synthetic?

outriggers

Anyone use it? Comments? I see my local Autozone stocks it.

On Time

What an incredible thread! All these years boating (about 30) I've used manufacturer recommendations only and I see a lot of other possibilities now!

Not that manuf recs are necessarily bad. Lets start with Mercury. How many Mercury oils are there?

At least three...
1 Original 25W-40
2 Blended semi synthethic 25W-40
3 Full synthetic 20W-40

Which one would be the best for 500/525EFI engines? I heard the most recent full synthetic Mercury oil has less antiwear additives (Zn, P) because of catalytic converter issues. Well, most of us don't have cats and want the best oil.

What about AMSoil Dominator 15W-50, Bob Teague's current racing choice? He runs 525's. They change oil after every race. Can you use this for 20-25 hours for average to hard recreational use?

Thanks, Andy