A
different spring will do nothing at idle with a hot engine. The oil pressure is
really a function of how much volume the pump can flow/and oil flow allowed. A
gear type pump is a positive displacement type pump. If there is no flow at all,
then either the pump has to stop turning or something has to burst to relieve
the pressure. If there is no restriction to flow, then there is 0 pressure.
Since cold oil does not flow easily, the relief valve is there so that excess
pressure can be relieved. When the pressure overcomes the spring pressure, the
valve will lower allowing oil flow through the relief port. This ensure
adequate flow. I've seen attempts at modifying the spring and using a rod
to hold the plunger up all the way. The rod resulted in shearing the tang
off the oil pump shaft. If the engine is loaded with gook, it is possible
that the plunger is not seating fully causing the valve to always leak. This
will cause low pressure problems at idle. So will a worn
pump.
Dennis
The oil on light at idle, is a common
problem in T1 engines. An oil booster
spring has been used to boost
the oil pressure back up to what is needed to
get more life out of the
engine.
The stock pump puts out 150 to 200 psi. The stock spring
is set to relieve
this pressure and allow only @10 psi per 1000 rpms or
about 40 psi at 4000
rpms (the ACTUAL psi might vary according to VW
specs, I do not have them in
front of me).
Adding the booster
spring helps to make up for the increased clearances due
to worn bearings.
I do not recommend using the spring as a substitute for a
rebuild,
but to get some more life out of the engine as you PREPARE for a
rebuild
in the future.
I would also not drive push the engine hard.
Bug Pack, Empi and several other makers have them. They are for
a T1 engine,
but should work in a WBX engine. The spring is about an
inch longer than a
stock spring. I will be putting one in an engine
that I have been working on
for a friend in the next few days.
**I
would ADD an oil pressure gauge to keep a check on the pressure during
running, so IF the pressure drops (with the spring) you can save the
engine.
My friends pressure, when hot drops to 23 psi at @3500
rpms. He has new rod
bearings (his old were worn out) We did a top
end rebuild, but did not crack
the case so I suspect that the mains are
worn and this is where the pressure
is lost. I will report back on
the results of the pressure increase later.
**The use of a
counterweighted crank eliminates this bearing wear because the
harmonic
vibrations that cause the wear are neutralized. The crank, because
it has two center offset journals, wants to FLEX in the center.
Adding
counterweights eliminates the crank flexing and the bearing
wear.
*This is one, if not the most important, modification I made to
improving the
life of my engine.
Robert