Effect Of Oil Ratio Tests Gordon Jennings 1978

[iconic558]

I keep hearing of this test and finally found it today.

 

What no one ever seems to mention (or I've missed) is how old this test is, published in 1978, although that may not be any cause for concern, but what is, is the use of Castor Bean oil, not mineral based oil.

 

I used to be an automotive test engineer and then went onto pure combustion research and a few of things from this report really bug me, all from the comfort of my armchair & not really knowing jack s**t about 2 stroke R&D. I was compression and spark ignition 4 cycle only ..or dirty diesels and gasolene's, sorry petrols outside of work.

 

OK, any test such as this, and this is a real biggie should have been an A, B, A test to have any meaning (such as 20:1, 30:1, 15:1 then back 20:1 again). There is no mention of barometric corrections which can cause errors both positive and negative and few other bits and bobs that may have been edited out for all I know but the author has gone to long lengths to go over the test methodlogy. If I made a mistake then I appologise up front, there's a lot of work gone into that report that much is evident.

 

Also, another biggie, the oil used is castor bean oil so it follows that it can't be assumed that it's relevent to petroleum based oils, be they mineral, para synthetics or synthetics, we like to compare apples with apples when testing things, keeps the anoraks happy.

 

Somewhere there is a Castrol or Shell test report (someone told me about it in the mid-90's at either Castrol Sunbury or Shell Chester) that shows issues arising from using too much oil in the ratio for mineral oils. I was doing enduro's at the time so it caught my attention.

From memory it was something to with having to work the engine so hard to produce enough torque due to poor combustion that it caused elevated piston crown/cylinder head temperatures etc going on to cause hot seizures. All of that sounds counter intuitive, but hey, these guys do know a thing or two about oil....not forgetting this would go against the all important internet conspiracy theory of "they want us to use to more oil so they can sell more so they would say that wouldnt they...ohh"

 

Anyway up, best bet is simple, run an SWM and don't worry, our Rotax lumps don't seem to be oil ratio sensitive from what I hear, and, my owners manual from back in late 70's states 50:1 on pure dinosaur oil....so all hail and kiss the toe's of the mighty & tough as old boots Rotax mill.

 

enjoy, if you like the smell of napalm castor bean oil in the morning....and it's even more fire on the "what oil for my bike and what ratio"....

 

 

http://www.bridgestonemotorcycle.com/documents/oilpremix6.pdf

Edited November 15, 2016 by iconic558

[shakennstirred]

Interesting read.

I like the bit were it says they changed the needle position and mains jets, so many people forget about doing this with there old 70s n 80s bikes,

when they start running at 50:1 or 60:1 when the manufactures jetted it for say 20:1. Its going to run rich on the fuel/air

 

In the case of my Beamish Suzuki's 20:1, you now start running it at 50:1 or higher, it runs to rich on the fuel/air.

I fitted a better flowing 2 stage filter on mine and opened the airbox a little more to get the fuel/air mix right.

She is running great and carbaration is just about spot on, very crisp and just pulls clean though the revs.

 

Had a go on a Beamish that was running around 70:1 with the stock jetting airbox etc and it was terrible

was bogging down and wouldn't pull clean though the revs and was hard work to ride.

 

 

Edited November 15, 2016 by shakennstirred

[brownie001]

Nice reading. Shows that back in the 70's a lot was undertaken and understood.

If you Google about a bit, you can find some more recent test's regarding premix oil ratios.

 

I personally like this companies attitude and products. http://www.maximausa.com/powersports/

 

There are some pretty conclusive tech papers and videos to be found there.

 

I have no personal interest in the company whatsoever.

[iconic558]

I've just got myself some Ipone strawberry scented ready to in the next fill.

I'm not sure if strawberries give a performance advantage, but if nothing else it's one of my '5 a day'

[iconic558]

Apple of my eye
Nice pear of...
Maybe strawberry is simply safer....

Bought a lemon
Feel a right plum
Grapes...hemorrhoids.....and sour
Oranges...errm sexual connotations
Pineapple meetings
Blow a raspberry


Have I missed any?

Edited November 16, 2016 by iconic558

[metisse]

I run my leaf blower with a drip or two of Castrol R in the petrol... just reminds me of what I'd rather be doing......

[iconic558]

I ran my Suzuki GT250A 1976 on Spry Crisp 'n Dry over a couple months back in 1982 when I so skint...tweaked up the CCI auto-injection and no problems at all...other than it smelt like greasy spoon cafe behind me....I can't believe I took the chance, things were soooo much easier back then .

 

Edited November 16, 2016 by iconic558

[shakennstirred]

I've just got myself some Ipone strawberry scented ready to in the next fill.

I'm not sure if strawberries give a performance advantage, but if nothing else it's one of my '5 a day'

I have the Putoline TT trial oil that's meant to be strawberry scented and to be honest I cant smell it.

It just smells like an ordinary two stroke oil .  

[suzuki250]

I ran my Suzuki GT250A 1976 on Spry Crisp 'n Dry over a couple months back in 1982 when I so skint...tweaked up the CCI auto-injection and no problems at all...other than it smelt like greasy spoon cafe behind me....I can't believe I took the chance, things were soooo much easier back then .

 

That's nothing. I was so skint once, I had to cook my chips in two stroke oil...

[iconic558]

I have the Putoline TT trial oil that's meant to be strawberry scented and to be honest I cant smell it.

It just smells like an ordinary two stroke oil .

I've heard that of the Putoline oil, but the Ipone is meant to smell of strawberry milkshakes.....I'll chime back when using it

[shakennstirred]

I've heard that of the Putoline oil, but the Ipone is meant to smell of strawberry milkshakes.....I'll chime back when using it

Not that im bothered it doesnt.

i had the bottle given me.

[feetupfun]

A friend in the 1970s ran his almost-new Suzuki Waterbottle (GT750) on straight petrol (with the oil injection system not functioning) for a few weeks of riding to work. He pulled the cylinders off expecting carnage but the top ends were still perfect

[dadof2]

From Jennings "the results can be given in a single, brief sentence: "Engine output and piston cleanness improves as premix oil content is increased." 

The above is a point I have made several times on this forum only to be criticised by quite a few. Graham Bell (another well renowned tuner) also favours a rich oil to fuel ratio.

The proper answer for trials bikes is a pumped oil system like the early TY Yams had. This gives the near correct ratio for all running conditions, pre mix never can.