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Thread: What 2 stroke oil yall runnin?

  1. #31
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    Lower cylinder wall temps would increase the viscosity of the oil on the walls, which might allow the oil concentration to be a bit lower to have the same effect.

    But OTOH I'm doubting that would be a big difference. Cylinder wall and pistion temps are a lot higher in air cooled engines than outboards and that is one of the key differences between the oils that are rated for air cooled and water cooled applications. So air cooled oils have more bright stock and therefore hold viscosity to a higher temp so that they don't stick rings of have scuffing near the exhaust ports at those higher temps. They are like grapefruit and oranges, they are both a bit different, but they are both citrus and there's a lot of similarity too.

    I'd still figure that the percentages where best power is attained is probably in the same general area, not up at 32:1 and certainly not at 50:1, and probably not down at 10:1 either. If the manufacturer told Tim they ran power and durability at 16:1 that was from their experience, so we have 2 data points in the same vicinity. Like I said, every engine is going to be a bit different. Some might like a bit more oil to seal, others might need a bit less, and it's going to change with viscosity of the oil you are using, the temperatures you are running, the clearances of that specific engine... It goes on an on.

    We aren't trying to nail a specific number for any specific or all engines, I just want to get in the ball park and find home plate, not specific blade of grass.

  2. #32
    Sam Cullis Mark75H's Avatar
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    I would like to thank all that have contributed the fantastic information on this thread!

    This is without a doubt the best 2 stroke oil thread I have ever seen.
    Since 1925, about 150 different racing outboards have been made.


  3. #33
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    Excellent indeed!

    Having been in the marine business for 40 years (OMG am I getting old), I've got to say the engines, oils, props, everything has gotten way better. My Super 10's ran 16:1, later models on 25:1, and Merc was transitioning to 50:1 at that time (1972). We weren't sure if the earlier models should be run on leaner oils, even though oil suppliers said you could. Plug fouling was certain reality with magnetos, so we tempted fate and tested. I remember stock outboard guys swearing they went faster on 50:1. Not sure about that, but plug fowling and smoke was greatly reduced, then disappeared when Thunderbolt ignition was introduced. Heck, they even ran stone cold surface gap plugs and still idled without fouling!

    The point I'd like to make is the oils have improved dramatically over the years, so you can get away with leaner ratios - even with basic production oils such as TCW3. As Yellowjacket, Zul8tr, Sam, and others have pointed out, there is no single best oil for every engine and/or application. It's great to test new products so long as good reasoning goes into the change and careful notes are taken.

    Too many times the product of many hours work was reduced to rubble because of unknown consequences for a new products. Example: A cam wiped lobes and spread metal throughout a new engine running the just released super-duper Mobil 1 synthetic in an OHC engine in 1982. Only after complaining to the Mobil techs directly did I learn the oil had not been tested in OHC's! Thankfully, better research & test methods, and the power of the internet help communicate problem products.

    Thanks to all for sharing. Please keep it coming!

    Tim

  4. #34
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    For those of you that have "Iron Fist" turn to page 296 and read about port clogging in the MK75 endurance event. It says ports were closing off while running at 4500 RPM with oil of the day (not specified) and white gas (non-leaded marine fuel for outboards in the early days). TCW3 (and other later oils) do not build carbon in racing applicatoins (my experience).

    Tim

  5. #35
    Team Member zul8tr's Avatar
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    Water cooled has more efficient heat transfer if the cooling chambers are properly designed and especially outboards with a constant supply of lake temp water. Air cooled can have dead spots behind cylinder and inbetween 2 cylinderes. My experience with air cooled is they definately run hotter and need to be clearanced properly for expansion.

  6. #36
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    I read an article a couple of years ago concerning two stroke oils. Ash was one of the subjects discussed and Pennsoil of all brands produced the least amount of ash. Another thing discussed was the difference between oils for water cooled and air cooled engines. I don't remember the exact terminology but air cooled engine oil is formulated so that the oil drops out of suspension at a higher flash point than water cooled engines due to the higher running temperatures of air cooled engines thereby getting to all areas of the engine before it drops out. I think it also talked about air cooled oils requiring a higher temperature to burn thus being able to lubricate cylinder walls at a higher temperature. This is the best that I can recall reading, but there are definite differences between the two. I also wonder about 2 stroke oil now being marketed for all 2 stroke engines. I would touch that stuff with a 10 foot pole if what I have read is true. I ran my Yamato last year on Mercury oil and this year on Red Line. I haven't looked inside yet but didn't see any differences in performance.
    kk

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    "Ash" sure was the problem back then, when I first started yanking the starter handle on my KG-7. The best oils were LOADED with ash and fouled up the works in short order.

    For that matter, 4 stroke oils weren't that much better. The old Ford Y-bock V-8s (243 to 312 cubes) weren't that bad an engine, but the oils available back then were not up to the way they oiled there rocker arms. The result was scored parts and whipped main bearings after metal particles (crappy oilfliters as well) contaminated the oil. Modern oils have sure come a long way.

    Any old Ford V-8 lovers out there?

    Jeff

    PS: A well set up Ford 312 would whip the best equipped Chevy 283 every time.

  8. #38
    Team Member zul8tr's Avatar
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    Agreed on the 312 and the 283. I had a 312 Auto with 4 bbl Carter in a 57 Ford Fairlane 2 door no pillar, white with crome and gold trim and black interior, nice car and a good runner. Had a race with a 57 Chev going across Texas on my way from Calif to Fla. He could not stay with the Ford in any gear.

  9. #39
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    Right! I recall several, spirited street races between by buddy's 57 Chevy and my sister-in-law's 57 Ford. The Ford cleaned house!

    Jeff

  10. #40
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    Quote Originally Posted by Fastjeff57 View Post
    "Ash" sure was the problem back then, when I first started yanking the starter handle on my KG-7. The best oils were LOADED with ash and fouled up the works in short order.

    For that matter, 4 stroke oils weren't that much better. The old Ford Y-bock V-8s (243 to 312 cubes) weren't that bad an engine, but the oils available back then were not up to the way they oiled there rocker arms. The result was scored parts and whipped main bearings after metal particles (crappy oilfliters as well) contaminated the oil. Modern oils have sure come a long way.

    Any old Ford V-8 lovers out there?

    Jeff

    PS: A well set up Ford 312 would whip the best equipped Chevy 283 every time.
    We had a 1958 352 that broke valve springs all the time. It wasn't that oil couldn't get to the rockers, it couldn't get out and sludged up in the valve covers preventing oil flow. Then the springs would overheat and break. The 383 Dodge my dad bought to replace his first and only FoMoCo could suck the headlights out of that Ford.

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