I agree the benefit of synthetics over conventional is less (around 2% improvement according to the study) than just using the correct viscosity (5.5% improvement) in terms of MPG. Friction modifiers provided about the same benefit (2.5%) as synthetic oil alone. These values are all at 20% load according to the study (page 562). A 2% improvement over a 10,000 mile oil change (@ 35MPG and $3.50/gal) is equal to $20. You've sold me on going synthetic.

I respect your observation that oil consumption increased in your car, and mpg reduced, for the period that you used synthetic oil.

 

In the early days of synthetic oil there were a lot of complaints from people that had problems from oil leaks.. I have no idea where I read that the problem was solved by adding regular mineral oil to the synthetic to solve the problem but I do know it was on a site that sold synthetic oil. They also said there is no longer a 100% synthetic oil being sold for automotive use... I need to say that the worse case of valve stem leakage I have ever seen was on a Honda 4 valve single cylinder XR 350 dirt bike that I raced on in the 80s... Other guys that rode and worked on 4 stroke Hondas all told me that they had problems with them also to the extent that the enclosed cam chain would not receive enough oil to stay lubricated and would wear out... We weren't even using synthetic oil in those things back then... I got hooked on Amsoil when I was riding a Harley that I was always tearing down and throwing $100 bills into so I could keep up with younger guys riding Hondas... The inside of that engine never had any kind of buildup discoloration or scoring like every other Harley I had been into seemed to always had and was considered normal.. I had to go to 10W30 Mobile1 to see if it would eliminate oil blow by when on full boost and it did help a lot... I think that the oil was bringing down the octane of the air fuel mixture since I am getting quite a bit more ignition advance and the exhaust fumes no longer reek of unburned gasoline as they had before... Also the fuel mileage is much better, there is more power and the CEL stays off most of the time unless I have to drive in heavy traffic on very hot days.

 

Mr. Mahout, I have a lot of respect for you but I have to disagree on the some of the cars with bad seals. Usually when you build a motor your using the best parts. Bad valve seals or valves is like the coil problems but it depends on what you do.

Moly tests is a subject to interpretation but they would not have a paper that says what it does if it is not true. There was a time that moly was the cause of sludge but that is old news.

 

I just did mine last week, I used the oil drain bolt with the car tilting back so as much oil could be drained as possible. I also replaced the filter so all the oil was removed as well. I put in a full 4 quarts. I checked the level today a week later and it read just at the maximum level dot.

 

I have no idea what your disagreeing with but I will offer one piece of advice:
Aways check the source of a proposal; if they stand to benefit from the presentation back up and investigate very carefully and thoroughly.

 

I agree and usually do investigate. I have had problems running synthetic oil with oil consumption in my last 2 Honda's and 1 van I still have. Talking to Tuners the first thing they do is replace the oil seals and valves before they add power boosters. Most people its just a nuisance but never gets bad enough to be considered a problem but that dont mean there is not a problem. Most conventional oil has synthetic parts added to it. So far 2 oil changes on dealer oil and no oil consumption at 19000 miles.

Moly pistons http://www.motor.com/magazine/pdfs/032008_07.pdf

 

I'm curious about 2 things:
1. how did you break-in your engines?
2. whose synthetic oil did you use?
There's been more than a hundred Hondas here over 34 years and only those with high mileage had oil leakage past seals; some did past damaged rings. Almost all ran on Mobil 1. I can make the same claim about Toyotas, Nissans, and Mitsubishi as well. Even Suzuki.
Any time you go with forced induction we use Viton seals for the high temperature capability. Yes, costly, but virtually foolproof in high temp and rpm.

As for anti-friction and anti-wear coatings on pistons they are more ceramics than simple molybdenum sulfide suspended in various fluids. They've been used in NASCAR and virtually all racing for decades. F1 is probably the most advanced tho NASCAR won't be far behind. I've long held that duPont's sponsorship of Hendrick was a sure path to better antifriction lubricants and surface polishes (think different polishes drivers and 'passenger's sides could make a difference? its a vertical wing and faster velocity creates negative pressure and don't think todays F1 and NASCAR teams haven't worked on that.)
We send any parts that we are preping for competition out to people that are skilled in that process. They won't let you in on their formulations for proprietary reasons so I haven't verified their components but I don't expect molybdenum sulfide to be the only anti-friction component. Or if its there at all. Take a look at one of those pistons or cylinder head coatings (mostly anti-heat transfer types) with a magnifying glass. Interesting. See any visible particulates?

 

Both Honda's after the first oil change around 5000 miles. I used M1 0w20,5w20. I really liked the 0w20 but was hard to find and the dealer would not use it after 2005.

I have nothing against synthetics, but learned about POAs. I will leave it at that and will take your advice and do better investigating.