Observations of Spark Plugs when using WI with OMP converted to 2 cycle oil
10-04-11, 04:35 PM
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Eye In The Sky
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Observations of Spark Plugs when using WI with OMP converted to 2 cycle oil
Plugs are NGK R6725-9 leading and R6725-10 trailing.
WI comes on at 7 psi boost and is maximized at 325 ccm at16 psi boost.
Oil and filter were changed before my 2200 mile round trip from Houston Tx. to Deals Gap N.C. for 2011 DGRR.
Engine oil has been Royal Purple 5W-30 since 1999. 2 cycle oil was Pennzoil Synthetic Marine Premium Plus 2-cycle. The trip was mostly fast cruising with boosting.
A short while after the trip, I was very surprised as spark plugs were dirtier than anytime that I have seen them. They were dark brown with a lot of carbon buildup.
Cleaning the plugs with my spark plug blaster was about the same as before conversion. Seems like the RP oil normal Mazda injection in city driving was burning cleaner that the Pennzoil 2 cycle cruising on a long trip.
Note: my colder plugs will run darker that the stock 7 & 9 plugs for cruising.
After a while, the engine oil and filter were changed again along with switching to my other set of plugs. The 2 cycle oil was drained and changed to Amsoil Interceptor.
1100 miles later “today” I pulled the plugs again. They were noticeable cleaner with light carbon buildup. Color was medium brown. The 1100 miles was city driving with boosting.
Surprisingly, the plugs were easier to clean with the spark plug blaster as the deposits came off easier.
The Amsoil Interceptor oil is definitely superior to cheaper oil.
WI comes on at 7 psi boost and is maximized at 325 ccm at16 psi boost.
Oil and filter were changed before my 2200 mile round trip from Houston Tx. to Deals Gap N.C. for 2011 DGRR.
Engine oil has been Royal Purple 5W-30 since 1999. 2 cycle oil was Pennzoil Synthetic Marine Premium Plus 2-cycle. The trip was mostly fast cruising with boosting.
A short while after the trip, I was very surprised as spark plugs were dirtier than anytime that I have seen them. They were dark brown with a lot of carbon buildup.
Cleaning the plugs with my spark plug blaster was about the same as before conversion. Seems like the RP oil normal Mazda injection in city driving was burning cleaner that the Pennzoil 2 cycle cruising on a long trip.
Note: my colder plugs will run darker that the stock 7 & 9 plugs for cruising.
After a while, the engine oil and filter were changed again along with switching to my other set of plugs. The 2 cycle oil was drained and changed to Amsoil Interceptor.
1100 miles later “today” I pulled the plugs again. They were noticeable cleaner with light carbon buildup. Color was medium brown. The 1100 miles was city driving with boosting.
Surprisingly, the plugs were easier to clean with the spark plug blaster as the deposits came off easier.
The Amsoil Interceptor oil is definitely superior to cheaper oil.
10-04-11, 06:21 PM
#2
Arrogant Wankeler
Most of the marine 2 stroke oils seem to be rubbish, even when rated & OEM approved for DI 2 strokes they smoke & foul in a rotary. A good synthetic motorbike 2 stroke oil seems to be teh best bet, although i use a cheap castrol oil with long plug life and they come out quite clean at 100:1 premix.
10-04-11, 06:25 PM
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Eye In The Sky
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Since mine is DI and not premix, maybe someone should start a premix thread.
The Interceptor oil is listed for engines with power valves to keep them clean from carbon buildup.
Amsoil responded to my inquiry recently saying it is their cleanest burning oil.
The Interceptor oil is listed for engines with power valves to keep them clean from carbon buildup.
Amsoil responded to my inquiry recently saying it is their cleanest burning oil.
10-04-11, 09:03 PM
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Eye In The Sky
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Just over 52,000 miles.
8 Feb. 2011 compression test with modern digital tester.
Front Leading: 126.12/123.67/123.67
Rear Leading: 121.22/116.33/116.33
8 Feb. 2011 compression test with modern digital tester.
Front Leading: 126.12/123.67/123.67
Rear Leading: 121.22/116.33/116.33
10-04-11, 11:05 PM
#6
I have been reading some literature on carbon buildup. This is from a published paper written by a Siemens engineer. It covers buildup of deposits in a combustion chamber and in all the intake-related systems. It's not a rotary-specific paper but it describes a lot of the trends and basic causes of deposits.
You can see that oil chemistry, engine running temperatures, and heatsoak conditions play a big role. Another interesting point that I wasn't aware of is in the second image shown above. It explains that carbon builds to a stable level and can pretty much stabilize at that level.
So here's something to ponder--if water injection cools surfaces, and low/low enough temperatures actually contribute to carbon buildup, you would think that in some cases it could actually cause a problem. However the intermittent nature of water injection, as well as its intermittent use and probably abrasive nature (scrubbing in a way) are probably why a cleaning effect has been observed.
You can see that oil chemistry, engine running temperatures, and heatsoak conditions play a big role. Another interesting point that I wasn't aware of is in the second image shown above. It explains that carbon builds to a stable level and can pretty much stabilize at that level.
So here's something to ponder--if water injection cools surfaces, and low/low enough temperatures actually contribute to carbon buildup, you would think that in some cases it could actually cause a problem. However the intermittent nature of water injection, as well as its intermittent use and probably abrasive nature (scrubbing in a way) are probably why a cleaning effect has been observed.
10-05-11, 08:35 AM
#7
Racing Rotary Since 1983
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very interesting and glad to see your plugs are back to a proper color which is light brown rather than black...
Cam Worth and i were talking premix recently and he made the point that "outboard/marine" 2 cycle oil is designed to run at lower temps and is not the right stuff for our engines.
howard
Cam Worth and i were talking premix recently and he made the point that "outboard/marine" 2 cycle oil is designed to run at lower temps and is not the right stuff for our engines.
howard
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10-05-11, 09:26 AM
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Fixed the wheelhop
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Thats the only 2-cycle Ive used for years...damn
It seems like the 2-cycle is either a few bucks a qt or $8-10 a qt for racing oils. Is the Valvoline 2-cycle any good? Or basically do I need to start buying the good stuff? Redline, Amsoil, Royal Purple?
It seems like the 2-cycle is either a few bucks a qt or $8-10 a qt for racing oils. Is the Valvoline 2-cycle any good? Or basically do I need to start buying the good stuff? Redline, Amsoil, Royal Purple?
10-05-11, 04:50 PM
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T67, did I say 7?
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The trip was mostly fast cruising with boosting.
A short while after the trip, I was very surprised as spark plugs were dirtier than 1100 miles later “today” I pulled the plugs again. They were noticeable cleaner with light carbon buildup. Color was medium brown. The 1100 miles was city driving with boosting.
Surprisingly, the plugs were easier to clean with the spark plug blaster as the deposits came off easier.
The Amsoil Interceptor oil is definitely superior to cheaper oil.
A short while after the trip, I was very surprised as spark plugs were dirtier than 1100 miles later “today” I pulled the plugs again. They were noticeable cleaner with light carbon buildup. Color was medium brown. The 1100 miles was city driving with boosting.
Surprisingly, the plugs were easier to clean with the spark plug blaster as the deposits came off easier.
The Amsoil Interceptor oil is definitely superior to cheaper oil.
Fast highway speeds mean lower water and intake temps. Most city driving is the opposite.
The great thing about most syn oils, they tend to offer a wide temp range.
In other words, they burn better if you live up north, or in the south. Or if your engine runs at 180*f or 240*f.
We could go on for hours on this subject (2-stroke oils), but it comes down to each engine, and how it is built and tuned.
I use Motul 800 2t in all my 2-strokes, and have been for the last 8 years. Is this the best oil on the market? Don't know, but so far it's the best I have seen.
So, when I went to premix on the rotor motor, I stayed with 800 2t and this works for my application.
10-05-11, 06:44 PM
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Eye In The Sky
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For 99% of my city driving temperature deviation does not apply. I have been retired since 2007 so rarely drive in stop and go traffic.
My Koyo "N" pass radiator runs between 83C and 85C between winter and summer. Stop and go rarely and barely affects it.
Only my FMIC air temps vary from stop and go and cruising but my "Air Temp Vs Inj" table is linear and not stock.
My Koyo "N" pass radiator runs between 83C and 85C between winter and summer. Stop and go rarely and barely affects it.
Only my FMIC air temps vary from stop and go and cruising but my "Air Temp Vs Inj" table is linear and not stock.
10-06-11, 12:33 PM
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So here's something to ponder--if water injection cools surfaces, and low/low enough temperatures actually contribute to carbon buildup, you would think that in some cases it could actually cause a problem. However the intermittent nature of water injection, as well as its intermittent use and probably abrasive nature (scrubbing in a way) are probably why a cleaning effect has been observed.
this is also why its not really worth worrying about carbon build up, it can only build up so far, and the cure is just to push the pedal on the right down, and leave it there. temp goes up, carbon comes off. if you've ever taken apart an engine that was really used hard, there won't be much carbon in it.
premix; i've been using valvoline in the P port, and in DD conditions, it doesn't burn it stays liquid. the engine very definitely wants less premix at less load. anyways, @full throttle is DOES burn, and of course there is enough heat to burn it all out of the exhaust too, so lap 1 is a smokescreen, but after that its fine, and the plugs look great
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