Oil pressure

[Mike Wattam <101714.1343@domain.elided>]

Bruce

The best thing about oil guages is, the Stag doesn't normally have one!

I don't, because;
1.  they are something else to worry about
2.  they are never accurate
3.  oil pressure is of hardly any consequence
4.  They don't measure oil flow
5.  oil pressure is controlled by the relief valve, more than the bearings

It is possible to have very high oil pressure but no oil flow through the
bearings, leading to failure.

Conversely, nil oil pressure may mean there is plenty of oil going through
the (sloppy but not failed) bearings.

If the bearings are worn out, you'll hear them.  Because the camshaft
chambers are fed by oil bled from the main bearings, if the bearings are
worn out the camshafts don't get fed oil, so noise rapidly develops.

I can more or less guaranteee that if you take off the oil pump and strip
out the pressure relief valve, you will find it is not correctly or fully
seated in the housing, and has badly worn on one side.  This causes poor
oil pressure idling when hot in particular and has caused many to strip
their Stags unnecessarily, rebuilt with new bearings and then found no
change in the oil pressure.

The spring used in later Stag oil pump relief valves is a terrible design
with about one third of its length being coil-bound.  It helps the valve
stick in its housing and has almost no movement, the spring rate is also
very high.  Re-engineered springs give a good consistent oil pressure at
all engine speeds and the valve does not stick.

So, what I am saying is don't worry about the oil pressure unless you have
other symptoms.  If you must still worry, look at the oil pump pressure
relief valve.

Mike Wattam
Triumph Stag Register