Clark Nicholls wrote:>
> This conversation is the first I've heard of a commercially available kit to
> take oil directly from the block oil galleries to the head!
>
> About 15 years ago I used this technique to get oil up there for a 1975
> Spitfire that was running dry in the rocker area. I just rigged it up with
> copper tubing from a block oil gallery plug to the head plug. As it turned
> out, it was dry due to the head gasket having gone bad. Replading that
> restored oil circulation to the head and the tubing was removed.
>
> I missed much of this discussion: is there a consensus that the amount of oil
> normally recieved in the head is not adequate?
Basically, yes. I was trying to instill a note of caution into the discussions
because if you're not careful you can
over-correct for this inadequacy and bleed too much oil away from the
crankshaft. The reason for the problem is
that the rocker shaft is the very last thing that gets oil from the pump and so
it is fed at very low pressure. As
the engine wears, oil pressure gradually drops and the rockers get less oil.
It's debatable just how much they do
need anyway, but it is crucial that the crankshaft is not starved.
As you rightly have pointed out there are other possible causes of this
problem, another being the build up of
sludge in the oil which can block the narrower oil passages. I believe this is
a problem with the low pressure oil
feeds to the hydraulic tappets on the Rover/Buick V8 engine, but we Triumphites
needn't worry ourselves with
that.
I have also heard it said that on the 2000/2.5 saloon/estate models this is
aggravated by the weird angle at which
the engine is mounted such that the rocker shaft runs noticeably uphill. The
suggestion is that in this case the
front rockers get less than the rear ones.
Phil
From: Phil Willson
Electronic Engineering
Queen Mary and Westfield College
London E1 4NS
Tel +44 (0)171 975 5338
Fax +44 (0)181 981 0259
email p.j.willson@qmw.ac.uk
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