Dipstick Accuracy & Oil Level

[Daryl Gatenby <Daryl.Gatenby@domain.elided>]

I noticed on one occasion that the dipstick retaining tube on my engine was
slightly bent (as a result of something coming in contact with it when the
engine was being removed I suspect). I applied pressure to the tube in the
direction required to straighten it and noticed that it had some up and down
movement. I think the retaining tube relies upon an interference fit to
secure it in the block. It moved downward about an eighth of an inch and
stayed there. So I suspect the dipstick itself goes further down into the
sump cavity these days and therefore shows the oil level as being slightly
higher than it really is.   

I was once told that one of the dangers of overfilling an engine with oil
was that if the level was too high the crank can thrash around in the oil in
the sump and aerate it. If this were a problem, I can't see it easily
happening to a standard Stag engine. The oil level would have to be really
high before the crank would contact the oil in the sump. Not long ago I had
the dipstick reading 3/4 over the high tide mark and didn't notice any
problems during operation.

I think also that there may be a benefit in having a higher than normal oil
level. 

Like some of you I have noticed that during heavy braking the oil pressure
takes a dive momentarily. This is most likely as a result of the oil pickup
running dry while most of the oil rushes towards the front of the oil pan.
Whether this fluctuation is detrimental to the engine's longevity was a
matter debated on this list not so long ago I recall. In any event I can't
see the phenomena as being beneficial. I'm not sure what quantity of oil
equates to 3/4 inch on the dipstick but I suspect it may be 0.5 - 1.0 litre.
I noticed that having the extra oil, presumably mostly in the sump during
operation, seemed to alleviate the surge factor during hard braking. 

I don't recommend it as a fix to this problem though. It is an untested
theory based on simple anecdotal observation.   

Daryl