so when i change the oil in my 12a i get more out than i put in, i always use castrol gtx, in the 4.5 l jugs, but the old oil doesnt fit into back into the new jug, its always got almost an extra litre, the car doesnt consume any coolant, and the carb is tuned well by a wideband, whats getting into my oil??????

 

That's... really hard to picture. Considering the engine consumes a little oil by design, you should see a net loss, plus any oil added between changes.

Does the old oil look normal coming out? Not really frothy/chunky/milky?

 

Fuel dilution.

 

+1.

 

There's only three choices: Water, fuel, or a miracle.

If the oil doesn't look contaminated by water (all lung-buttery and such), then it's gotta be fuel. Quite a lot, if it's one quart for five. Probably flammable as hell.

 

+2

My fpr was set at 3.5 psi when I was having the same problem, I lower the psi to 3 and problem solved! That is with the nikki and open exaust.

 

Is it hot when you drain it? I don't know how much, but it will expand when it gets warm, and it's cold when it goes in.

 

Thermal coefficient on motor oil's probably not anywhere near 0.2, though. Probably a couple orders of magnitude below that.

 

fuel dilution is likely it, oil has a faint smell of gas though i would expect strong fuel smell when diluted?
so what can i do to reduce or solve this?? or is this stuck oil control ring(s) that require rebuild

 

sorry i didnt mention. weber ida 48 with no oil injection/ never top up have never needed to no consumption, and changed every 4/5k km
I premix 2stroke, so no consumtion there, i have a pcv plumbed into the lower intake manifold for crank case ventilation and it keeps the fill cap clean and dry no lung butter, when draining its basically fine just thin considering i start with 20/50

 

that would mean that it was running rich, but i'm tunned and monitored with a wideband o^2 (aem)and it barely ever gets below 10.0 afr and when it does its only a bounce for a second otherwise its tuned 11.5/14 afr's, i have heard of fuel dilution of oil happening with prolonged operation at afr's (less than)<10.0 but i solved that issue a long time ago and its still diluting

 

11.5 is still kinda rich, and b how fresh is the motor?

 

so i switched up the idle jet, the range is about 12.5/15 for afr's now, and changed the oil, and double checked the level at just a hair over full, now to see if these afr's makes a difference.

the motor is still strong with compression, about 110psi all round, at about 70k km(almost 45k miles) on this rebuild, starts like a charm hot or cold,

j9fd3s'
what mixtures do you keep around having an ida,