Synthetic oil for 4-strokes?

[alpapale]

Re: Synthetic oil for 4-strokes?

Hey Dunk,<br /><br />I've been think out this winterization point you made a few posts back, and I have a question. As far as winterizing why would'nt you just use Fogging oil regardless of what type of oil you leave in the crankcase for the winter? You're not suggesting that the oil in my crank is going to evaporate?

 

[ODDD1]

Re: Synthetic oil for 4-strokes?

Walter, the #1 thing with 4stroke O/B winterizing is stabilizing the fuel....the mercs I have worked with are prone to carb gumming....the passages in these carbs are VERY small...one spec of crap and you are down a cylinder....

 

[ODDD1]

Re: Synthetic oil for 4-strokes?

Jeese, I forgot the other half of what i was gonna say...I agree sythetics give aditional protection above and beyond a fossil oil...but I have 2 problems with it....in my area people dont put alot of hours on a boat, 30 hours a season is average....will mineral oils protect as well in that peroid of time with 'average' use ? I think so...<br />The second is packaging....most sythetics are a very thin base stock oil...usually a 5w or a 10w....alot of 4 stroke motors get used for trolling ALL day and end up with fuel contamination in the oil...on the great lakes we commonly see trolling motors that 'make oil'...even the 10w40 that is spec'ed is not adequate...a 25w40 however will keep the oil pressure light on the dashboard off...<br />I like synthetics with heavier base weights..some even spec'ed as a straight weight oil..like a 30w are usually sold as a'race oil' and not easy to find...and the price will make you reconsider...

 

[alpapale]

Re: Synthetic oil for 4-strokes?

Hey ODDD1,<br /><br />What about a 5w-50 synthetic, like Castrol's Syntec which can be readily found (sometimes on sale)?<br /><br />Also, In my Volvo-penta engine manual, synthetic oil is recommended for the higher displacement and I believe optional for the smaller motors. Interestingly enough, I think it's a straight 30w. (I'll check on this)I know the lower unit oil they spec. is synthetic, how do you feel about synthetic in the lower unit?<br /><br />One more question: What about a carb'ed I/o motors when it come to winterizing; do you still fog the motor? It scares me to think about sucking oil through the carb and those "thin passages". I know when I fogged my old two stroke O.B. it was a "B" to get started in the spring.<br /><br />Thanks.

 

[ODDD1]

Re: Synthetic oil for 4-strokes?

the 5w 50 you are thinkin about is still a 5w base stock...I think is too thin...<br />the larger displacement volvos [7.4 liter an up] use an oil cooler to regulate oil temps [and viscosity].....the inline and small block motors do NOT....so when you come off plane and idle with a hot motor, you may not see ANY oil pressure...a screaming nightmare for the warrantee dept., even if nothing is wrong with the motor...hence the different recommendations....<br /> sythetic /synthetic blend gear oils are a godsend...I use them exclusively..if you have a SX or newer drive you should be useing it<br />for fogging you should use afogging oil that doesn't gum up...some I have seen turn into tar if left 6 months...personally, I like merc's 'storage seal' is nice stuff....

 

[Big Four]

Re: Synthetic oil for 4-strokes?

alpapale, The crancase on a 4 stroke is sealed compared to a 2 stroke. The fuel/oil mix does not pass through the Crankcase on a 4 stroke like a 2 stroke. So it doesn't matter what you fog it with the fogging oil never sees the crankshaft.<br /><br /> Yes my concern would be the crankshaft. If the last coating of syn oil dry's/evaporates off the crank and bearings over the winter storage rust could develop. I think if I was winterizing a 4 stroke OB I would change the oil to dino for the winter, run the fogging oil then change it back to syn to run with the next spring. It would be an excellent way to flush the crankcase of engine once a year. <br /><br /> Remember the engines he was talking about are 2 stroke engines so the we're talking watered(fuel) down Syn oil compared to the straight stuff in a 4 stroke crank. The fact still remains they don't have the rusting problems with regular 2 stroke oils even watered(fuel) down.

 

[alpapale]

Re: Synthetic oil for 4-strokes?

What you guys say about multi-viscosity oils is correct for non-synthetic oils. They add polymers to the thinner stock oils which prevent them from thinning out under higher temps. They do-not add polymers to synthetics! The oil itself has a much higher useable temperature range. Check out this article called "more than you ever wanted to know about motor oil" .. http://www.rconcepts.com/beard/dragnet/drag/oilinfo.html. I think it's a well-written unbiased article (with actual data)

 

[alpapale]

Re: Synthetic oil for 4-strokes?

As per my previous post:<br />the bulletin board included the period in the link http://www.rconcepts.com/beard/dragnet/drag/oilinfo.html this link works!<br /><br />Happy boating!

 

[alpapale]

Re: Synthetic oil for 4-strokes?

At the risk of beating this topic to death, I've learned that Volvo-Penta reccommends (in their 2001 maintence manuals) the use of "dura-lube" which is a 30w synthetic. I've also learned that they fill the crankcases of new motors with dino oil to allow them to brake in. Apparently (according to the dealer)the synthetic is not a good oil for break-in because it reduces friction so well that the rings can't seat properly. So what does that say about the long-term effects of synthetic oil vs dino-oil in normal use? ...(We already covered the abnormal conditions, i.e. overheating)<br /><br />Happy boating!

 

[Liam]

Re: Synthetic oil for 4-strokes?

People, If synthetic oils were to evaporate over time, in the winter, would you not expect them to evaporate much quicker in summerttime with the engine running at top speed and heat? Synthetic engine oils are not like WD-40 which uses an evaporative solvent to carry the oil.<br /><br />Hope this helps,<br /><br />Liam

 

[ODDD1]

Re: Synthetic oil for 4-strokes?

Yer right Liam...be kinda funny to see all the quarts of syn with loose caps evaporate jes sittin on the store shelves....

 

[Salmonator]

Re: Synthetic oil for 4-strokes?

fwiw, I had a newer 8 horse Honda and tried some Mobile Delvac 1 syn (5w40) that I had leftover after filling my Dodge diesel. I used this as my troller and it didn't take long before the plugs started fouling regularly and I noticed I was getting fuel build up in the oil as the level was rising. Went back to castrol 10w40 and the problem went away... Joe

 

[alpapale]

Re: Synthetic oil for 4-strokes?

Joe,<br /><br />Can't even begin to explain why this could have happened, except maybe you over-filled the crank?

 

[Liam]

Re: Synthetic oil for 4-strokes?

Lighter weight oils can seep through the piston rings fouling the plugs. The opposite happens if you carb float sticks open. You end up with gas in your oil.<br /><br />Liam

 

[Salmonator]

Re: Synthetic oil for 4-strokes?

Alpa, it wasn't overfilled. I'm guessing with the plugs fouling, maybe the cylinders were running pretty wet with gas and maybe that's where I was getting the seep into the crank case? All I know is that my honda didn't like that 5w... Joe

 

[alpapale]

Re: Synthetic oil for 4-strokes?

Salmonator,<br /><br />The interesting thing is that the two oils are very similar in viscosity, that is they are essentially both a 40w at operating temperatures. The 5w- acts only like a 5w at freezing tempertures, then takes on the properties of a heavier oil when its warms up. The 10w does the same, except it starts as a 10w at freezing, etc. If, in fact your problem is related to viscosity, (and I really don't belive that to be the case) then the same 5w-40 in a non-synthetic formuation would have caused the same problem.<br /><br />I still have a hard time blaming your problem on the fact that is was a synthetc. However one posibility is that if you have new rings not broken in and seated. Then possibly the synthetic does'nt burn as easily during combustion and hence your fouled plugs and subsequent gassing. As I stated in a previous post, the synthetics reduce friction so well you can't use them to break in a motor as the rings will not seat properly. How may hours do you have on this motor?<br /><br />Good luck--happy boating!

 

[Salmonator]

Re: Synthetic oil for 4-strokes?

The motor had about 40 hours on it when I switched to the Delvac 1. Many of those hours were in cold water (39 to 50) but not freezing temps. Your suggestion as to the synthetic not burning as well makes sense. All I know is that 10w40 castrol made it all better.... Joe

 

[AV8R]

Re: Synthetic oil for 4-strokes?

With 17 years of aviation maintenance under my belt in an industry which has been using synthetics for some time, and money typically not being a consideration, I definitely do NOT recommend synthetics to my customers. Internal engine condition on those using synthetics is usually worse than those using fossil fuels. This is not proven, only an observation. Perhaps those who run synthetic oils are more abusive to their enignes. Many factors could affect this, AND boat engines and aircraft engines are radically different. Just thought I'd add my 2 cents.