What causes ring sticking? I've read on the net it is from oil getting hot, then the ring scrapping the walls and the varnish stick in the ring and groove. Also, i've read this comes from the viscosity improvers shearing and sticking. So, why would we not use straight weight 30 or 40 in our boat engines instead of a Pennzoil or Chevron conventional 15w40?
what causes ring sticking
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If I owned a covered motor ski boat with light valve springs and a hydraulic flat tappet , or roller tappet hydraulic cam , myself I would use a straight wt if I chose a dino . Idle time out of the no-wake zones ect would be a non issue for me in terms of warm up .
Some of those flash points get up near 500F .
A motorcycle can crush those polymers used in HDEO 15w40's just like Godzilla crushed Tokyo
Boat engines tend to get fuel in them . Gasoline type fuel . I don't want gasoline jacking with the plastic polymers either .
Straight grades would be a win win for me at least .
Boat engines tend to get fuel in them . Gasoline type fuel . I don't want gasoline jacking with the plastic polymers either .
Straight grades would be a win win for me at least .
It's my understanding that VII are actually more tolerant of gasoline than the rest of the package.
Well very few straight weights are available with good additive package outside of a few speciality products. Modern HDEO's are tested to reduce ring sticking and will handle more fuel,soot,varnish and loads then most single weight oils. Running an oil with now VII in the form of polymers is even better! Synthetics can greatly reduce the problems associated with conventional oils and ring fouling.
Fixing what ever is causeing the oil consuption would also help. The more oil an engine burns dureing operation the greater the problem. If it has worn rings, valve guides, valve seals ect..... no oil is going to help it!
Fixing what ever is causeing the oil consuption would also help. The more oil an engine burns dureing operation the greater the problem. If it has worn rings, valve guides, valve seals ect..... no oil is going to help it!
Operating the engine at a easy on the engine rpm is one of the causes of ring sticking .Cat engine has a bit of informatiom on their web site. Cat recommends single grade oils for that kind of use . In your recreation boat that won't be a problem if the rpms vary and at 80% + rpms the rings move alot in the groves which helps keeps them clean.
What are boat engines? They are car engines that are modified for marine use. The st. weight and multi's have been discussed a lot here. The reason a lot of us are going 15w40 is that they are indeed HDEO's. These type oils are known for their resistance to fuel dilution and have a strong additive package, which is agreed by all, a MUST for boat engines given their living conditions. Also, boat engines run a lot cooler than car engines, so your not going to have to really worry about flash points. Fuel dilution will burn off as long as you actually "drive" the boat. Some of the problems with st. weights is oil pressure, especially for us 4 banger owners. Using a 40 weight oil will tend to keep the oil pressure at it's design maximum, with little room for more. Also with a multi, it gives you more protection when your running the boat cooler. Most thermostats on at least Mercruisers are at 160F, I think. Takes a while to build up that temperature. I like to think that with the multi that I'm using, I got protection until the engine is running for a while and the thermostat is doing what it's suppose to do.
Boat engine water temps are cooler. But the oil can easily go up to 260-300 after a hard run. Ask anyone who has an oil temp guage. At these temps, a 15w40 will break down. This is why BBC recommend straight 40w. I think someone had a thread about whay to run in his BBC in this section.
As long as weather is about 55 F or higher when you start the engine cold, and would also depend whether you are using a monograde 30, 40, and especially 50. I've seen on Castrol bottles for 30HD and 40HD print that says do not use below 40F, I think was for 30HD, and i think 60F for 40HD. I fish into October and November, and is very common for temps to get below 40F, especially those 5am trips. So definitely no monograde oils for me.
My old man religiously runs monograde 30 oil in 1976 307 chevy's in his boat. And he had to have the head worked over for a leaking exhaust valve seal last season or the year before. The boat needs new motors in general because they're so old and not that well maintained, but I know most of his valvetrain problems are from running monograde 30 oil in < 50F temps. The oil doesn't flow well when cold and increases startup wear, especially on the top end. And the engine that just had the problems was the one that was rebuilt around 1990. He has all kinds of problems every season
With 15w40 oils, they are going to flow much better at all temps, especially when cold. My '89 F250 with a 7.3L diesel starts with no problems at 5F and I run 15w40 in that, and have a used oil analysis in the diesel used oil analysis section to prove it. I don't think with today's technology invested in motor oils that any name brand SJ-SL oil is going to cause any problems with shearing and ring sticking... when used within reason, ie don't run a conventional 10w30 in a boat engine for 200 hours.
Don't forget mercruiser's 25w-40 oil. That's multiviscosity and what they expicity recommend/require. So even they, who for the longest time only said monograde conventional oils, is now on the multiviscosity bandwagon. And from what I hear they now have a synthetic blend version, so they're jumping on that bandwagon too. I'd be willing to bet the reason why it's a 25w-40 instead of a 15w40 is whoever Merc is using to produce the oil doesn't have the technology & know how like Exxon-Mobil or chevron does in blending and formulating oils, or it's a monetary issue in cost of base oils and additives and "acceptable" performance versus profit margins.
As far as I know, "ring sticking" is just the term describing carbon buildup on the rings preventing them from sealing and giving good compression. For 4-stroke engine it can be caused by oil breakdown at high temps or contaminants in the oil in general forming deposits at cold or high temps. In the case of 2-strokes, the oil is not burning clean enough and leaves deposits. High ash oils for this reason are avoided because of this.
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