Excessive 'Mayonnaise' in oil

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For years like a lot of owners here, I've suffered with this, the result of too many cold runs and not getting the oil hot enough. That I understand and for most of last year the small 100cc catch bottle collects only water from the tank breather, about 50cc every 200 miles. There is rarely oil or Mayo' in it. However, having pulled the one way breather off to clean after a fast 100 mile each way in lower temps (15-16c/60F) it and the breather were full of oily sludge. 3500 miles this year and have never seen such a mess. Since I'm going to treat her to new rings the top end will be apart and I'm thinking is it worth going further and doing the JC mod to add a lower drain hole in the timing case? Or am I deluding myself that if I reduce the timing side oil volume that might have an effect on what the breather is ejecting.
I have 850 cases on a 750, one way breather and tank venting to that catch bottle. Any thoughts?
 
Gooday Keith,

I have Commando's just open to the atmosphere and with a reed valve. I have never experienced what you describe in summer or winter, long or short trips.

Maybe it does not get cold enough here.
 
Wow thats different.. Change the oil n filter plus the oil tank to eliminate water... find some cheap "OK" oil and flush the engine (to op temp) with a sacrificial filter or 2 and same again x 2..... this will get the moisture out of the motor.... If your worried about the cost of 10ltrs of oil and a cuppla filters then stick with mayo

If it shows signs of mayo after several flushes then there is an input of moisture from somewhere..........

"Excessive" mayo............ There should be none!!!!! IMO...........
 
If you are stripping the engine that will allow a clean sheet after thorough internal cleaning, I think in severe cases moisture might burn off but there will still be sludge left dependent on the geographical climate.
Condensation can start in storage, fresh oil after a good run prior to long storage helps,the oil tank cleaned out might be a quick test.
I don't think you can truly flush it away with oil changes, more regular oil changes than normal after the system is cleaned is something else.
 
I forgot to ask, I wonder if a dry sump engine is more susceptible with external oil storage (in climates that promote condensation)
 
Thanks gents. I've no problem with flushing and cleaning, that would be done anyway. I was more interested in whether lowering the timing case oil level might have an effect. I'm not even sure why I asked but maybe someone will have an opinion on that. The bike has done over 39,000 miles in my ownership and its always been a bit of an issue, just not as bad.
 
There are posts on drilling lower holes in the timing side engine case but forget if that was combined with the Jim Comstock type reed valve unit.
Someone will post up.
 
I thought the milky oil was to do with combustion .not air/water drawn into the system?




Time Warp said:
If you are stripping the engine that will allow a clean sheet after thorough internal cleaning, I think in severe cases moisture might burn off but there will still be sludge left dependent on the geographical climate.
Condensation can start in storage, fresh oil after a good run prior to long storage helps,the oil tank cleaned out might be a quick test.
I don't think you can truly flush it away with oil changes, more regular oil changes than normal after the system is cleaned is something else.
 
I doubt that drilling the lower hole in the timing chest will help with condensation in the oil.

The water in the oil comes from exhaust gas that leaks past the rings on the power stroke. Exhaust gas contains 1 gallon of water [in vapor form] for every gallon of gas burned. It is a byproduct of combustion and has very little to do with ambient humidity.

If the crankcases and breather are not above 212 degrees F. then there will be condensation of this vapor. Short trips and cold temperatures that keep the engine below the boiling point will make more "mayonnaise".

More leakage past worn rings will also cause more water vapor in the crankcase. Jim
 
That explains why you see so much water vapour coming out of tailpipes on cold mornings and warmups. Didn't know there was so much water involved. :shock:
 
comnoz said:
I doubt that drilling the lower hole in the timing chest will help with condensation in the oil.

The water in the oil comes from exhaust gas that leaks past the rings on the power stroke. Exhaust gas contains 1 gallon of water [in vapor form] for every gallon of gas burned. It is a byproduct of combustion and has very little to do with ambient humidity.

If the crankcases and breather are not above 212 degrees F. then there will be condensation of this vapor. Short trips and cold temperatures that keep the engine below the boiling point will make more "mayonnaise".

More leakage past worn rings will also cause more water vapor in the crankcase. Jim
I am open to all and anything to gain knowledge.
I must say I have never heard of a water content in exhaust gas. How can that be ? Water in fire? I think the reason behind the mayo is simply cool riding conditions and not trips long enough to dry up the condensation. My MK3 with no special crankcase breather will spot the garage floor with a quarter size drop of whitish oil mix from the tank vent in cool weather but just barely sometimes a drop of oil when the weather is warm. There is never any H2o/oil mix evident in the tank. This oil tank vent is the one that used to go to a separator for the carbs and air box and now just down to the ground.
 
I doubt that drilling the lower hole in the timing chest will help with condensation in the oil.
I think I was expecting that! My logic was excessive oil getting churned to a foam in the timing case and passing up the breather along with moisture. It was just an exceptional amount this time after a longish and pretty hard run. Ambient temps were down but the engine was working hard. I have certainly noticed compression is down when cold, hence the re-ring thoughts. When the engine is hot it is hard to kick over, not tight but will certainly support my 180 lbs for a minute or two. So if ambient temp has little to do with the vapour content then it is just the lower engine temps in cold conditions that contribute to water not evaporating? Thanks Jim.
 
From Wilcopedia

"In complete combustion, the reactant burns in oxygen, producing a limited number of products. When a hydrocarbon burns in oxygen, the reaction will primarily yield carbon dioxide and water. "

A gallon of gasoline weighs 6.3 pounds and is comprised of 87% Carbon (C) and 13% Hydrogen (H). When you burn gasoline, a chemical reaction occurs, using Oxygen from the atmosphere. The Hydrogen and the Carbon separate, then recombine with Oxygen from the atmosphere to form H2O, or water, and CO2, or Carbon dioxide.
 
OK but still, blowby would have to be really excessive for enough exhaust and hence the water vapor by-product of it, to get into the case and actually get churned up to cause mayo, would it not? I still think it's a matter of an oil tank cooling and creating simple condensation. I re-read the op and it seems that in that oiltank vent catch is where the mayo is, not the engine proper.
 
Biscuit said:
OK but still, blowby would have to be really excessive for enough exhaust and hence the water vapor by-product of it, to get into the case and actually get churned up to cause mayo, would it not? I still think it's a matter of an oil tank cooling and creating simple condensation. I re-read the op and it seems that in that oiltank vent catch is where the mayo is, not the engine proper.

The air from the crankcase is 99% blowby -ie burned exhaust gas. Sure -when it enters a cool oil tank then that is where the water is going to condense out.

If you can't believe there is that much moisture coming out of your crankcase vent then warm up your engine and point the vent hose at a chunk of cold steel or a cold mirror. The water drops will form immediately -just like it does if you hold it behind the tailpipe. Jim
 
How much H2O or water is produced from a gallon of fuel:

A H2O molecule has two Hydrogen atoms (atomic weight 1) and one oxygen atom (atomic weight of 16 each). Each Hydrogen atom has a weight of 1, and the oxygen atom has a weight of 16, giving each single molecule of H20 an atomic weight of 18 (2 from Hydrogen and 16 from oxygen).

Therefore, to calculate the amount of H2O produced from a gallon of gasoline, the weight of the Hydrogen in the gasoline is multiplied by 18/2 or 9.

Since gasoline is about 87% carbon and 13% hydrogen by weight, the Hydrogen in a gallon of gasoline weighs 0.8 pounds (6.3 lbs. x .13). We can then multiply the weight of the Hydrogen (0.8 pounds) by 9,

>>>which equals 7 pounds of H2O or water and water vapor.
One US gallon of water weights about 8 lbs.

One US gallon of gas weighs 6.3 pounds<<<<
 
So those crankcase vent gases exiting are just full of water vapors and nasty blow -by/combustion gasses too. Why vent them back into the oil tank at all , to be recirculated by being absorbed back into the oil ? Seems a catch can with vents to outside air a good option ,no pollution control laws in mind here. :|
 
All piston ring engines have significant blow by with combustion moisture so a universal issue in any engine not run up to full operating temperature often enough to evaporate out most the water. Mayonnaise is poor lube, heat carrier and corrosion protection. This is reason for thermostatics on oil coolers and even special covers sold for cold weather protection. Hope we can learn why this particular Cdo is making sandwich spread.

Most the references I see say gasoline weights 6.5+ lb/gal.
 
In Keith1069's original post he said that regularly there was 50cc of water in a catch bottle that he needed to empty every 200mi, and on one occasion after two fast back to back 100mi rides the 100cc catch bottle and a one way crank case vent valve was full of sludgy white stuff, "a mess". The post ends with "any thoughts?".
We've done a lot of math regarding the source of water in crank cases and I'll certainly acknowledge that there is, but regardless the question is how to get rid of it. Keith, you seem to be accomplishing that. The crankcase and attending vapor is getting drawn out of the crankcase just fine, as far as I can tell. The issue, it seems is the collection of spew at the valve and catch bottle. So my thoughts on this is just get rid of both. Apparently that is where the vapor is condensing. As I mentioned a few posts back I merely run my tank vent down towards the ground and get very, very little in the way of oil drops. And in colder weather just a we bit of mix. This I may add is evident after an overnight park not whilst running. Nothing on the rear tire or any other parts of the bike either. That's all I got.
 
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