Oil usage

[Tdm]

Try dropping the amount of oil you put into the sump.
Just because an engine has a top mark on it's dipstick doesn't mean the engine has to have that amount swilling amount in the sump. It's well known that any internal compression in the engine (there's always some, it's just a big pump with the pistons thrashing back and fore splashing the oil around) will get forced out of convenient passageways in the engine or burnt unnoticed.
Try allowing the oil to drop to the halfway position on the dipstick and then monitor it...oh, it doesn't necessarily mean the engines need rework either, I have worked in Truck dealerships (various marques with different models) and new vehicles will often do the same.
Micky

Micky could you expand on the statement I have highlighted in red please. I have always used the top mark on the dipstick when filling up, are you now saying that by reducing the level of oil the air/space above is greater and therefore not compressed as much and as such there is a lesser force on the oil being circulated, and less chance that it will be forced out of any weak points?,
or have I misinterpreted what you are saying. I am interested because at present I have had a few more oil lossage problems than previously, and which I am trying to eliminate.

[Lingen]

TDM.
Butting in rudely, but there is no "Compression" occurring in the crank case unless the breather system is blocked. On the contrary, there should be a slight vacuum in there. That is why the engine tends to stall at tick over if you remove the oil filler cap, as air is drawn in to the carburettors via the crank case breather hoses, and weakens the air/fuel mixture.
Mike.

[Motorsport Micky]

TDM.
Butting in rudely, but there is no "Compression" occurring in the crank case unless the breather system is blocked. On the contrary, there should be a slight vacuum in there. That is why the engine tends to stall at tick over if you remove the oil filler cap, as air is drawn in to the carburettors via the crank case breather hoses, and weakens the air/fuel mixture.
Mike.

As much as you'd like to think so you'll certainly find a positive compression on engines at various times in their lives, as you point out one of the major source of oil leaks on engines, and certainly on TRs are a breather system which has the PCV valve which has a restriction in it.
However to pick up on TDMs post above the spinning crankshaft and pumping pistons create an oil mist within the crankcase which at various times is under vacuum and then compression, rear crank oil seals are favourite places for oil leaks because the compression available even if only intermittently "ratchets" the oil contained in the mist caused by excess oil, along the crankshaft and out through the seal.
As I pointed out this happens even upon new engines (not all) and it's a well known instruction to the drivers by dealerships "to only fill to mid position of the dipstick markings". It's perfectly acceptable, the engine still has adequate lubrication (otherwise it would only have a "must fill to here" instruction) with drivers filling at short intervals.
With the advent of electric gauges for oil level assessment on vehicles seemingly this oil usage condition has increased. After visiting customers and watching how the drivers checked their trucks in the mornings we found certain instances where they would start their trucks and move it onto the fuel pumps and then check their oil gauges after the truck had been fuelled. Not surprisingly over a week the build up of oil then trapped within the block instead of the sump led to considerable overfilling and consequent seal blowing or oils being burnt off. The motto being "there is no instruction so simple that a dimwit driver can not screw up "!

It may be that running with a lower sump level of oil has no affect and there is a condition that requires an engineering solution, but just as an overfull header tank on a radiator or the radiator itself will often cause a water spillage, I would always reduce the level of the fluids to help determine what is happening within the engine.

Micky

[Tdm]

Thank you Micky for your detailled reply.
I have discovered a small oil leak from one of the rear Inlet Manifokd ports since I last posted.

I have some old "Dirko" sealant that I am going to apply around the port in question tomorrow to see if it stops my current leak or not?

Fiiting the Weber Carburretor last November has caused a few anomolies? but the car does seem to run better and is far more responsive than it was before.

At least it gives a man getting on in years something to keep him occupied!

Apart from enjoying the Sunshine and cheap price of Beer & Food, working on the Stag still gives me something to look foreward to each day.