Talk Morgan Forums Morgan Sports Cars Morgan Three Wheeler & Super 3 Oil level,

You are probably correct Calum. And it is probably hastening the demise of the wimpy battery.

There are only three routes (the hoses) for oil to drain back into the engine after shut down, plus whatever oil drains back from various places in the engine such as the rocker boxes and cam chest.

Looking at the hoses first:

Because the return line terminates above the tank oil level, drain back from that line is limited to the < 1/10 liter capacity of that hose. (I'm using 30" hose lengths here to estimate. I believe the actual length is shorter)

The maximum amount of oil that could return via the smaller vent hose would be something like .05 liter, and that hose terminates above the oil level in the tank also.

So that leaves the primary culprits as the oil feed line (routing through the oil pump) and the drain back from other parts of the engine. Without knowing how much oil is present in the non sump parts of the engine during normal running, it's anyones' guess as to how to apportion their respective contributions.

Obviously the combined amount is substantial, based on forum posts. And I agree with Callums conjecture on wet sumping making for harder cranking.

BTW-I cycle the key 2-3 times with 2-3 second pauses between cycles before cranking if the car has been standing for some days, and that really seems to help starting. My conjecture, as yet unproven, is that the fuel system provides an extra amount of fuel on power up, and the multiple key cycles provide multiple enrichments.

I noticed that the oil level rises a bit when the oil is really hot and has expanded.
Therefore I check the oil after a long drive when the engine has really warmed up immediately after switching off the engine.

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Maybe I took things too easy but I have no degree in rocket science so I filled up ½ liter of oil whenever the level was below the bottom indicator. Could have been all wrong but my M3W survived several years and plenty of miles with that philosophy.
As far as I remember never needed more than a liter per year, milage 3 - 5000km/year.

So long as you have run it for a very short period before you check it you should be fine. The two markers can be thought of as the upper and lower marks on a normal dipstick to anywhere, so anywhere in between covering the bottom on und under the top one should be fine. Dont let it run for too long as you will get a froth of bubbles on the top which makes judging the level difficult. ITs just air from the scavenger pump and they come out eventually!

Indeed. I believe each time the key is turned to on, the fuel pump runs for a few seconds then shuts-off. As far as I can tell, this is ECU timer-driven and has nothing to do with fuel rail pressure. If you leave the ignition on, engine not running, the pump will not run again that key cycle. Had a devil of a time sorting an electrical problem to my pump until someone mentioned this behavior to me! By the time I could get my meter on the pump leads, the ECU had turned off the power...