>>Steve,
>> good thing I stopped by my machine shop this morning. I just happen
>>to be working on the mod for the pressure relief valve and I wanted to
>>find out what the stock pring pressure was on the valve. I thought it
>>would be somewhat high, since it seemed to take a little effort to push
>>in the plunger. Not so, on both the valves I tested the PSI was less
>>than 10 lbs. One was around 8 lbs PSI & the other was 6. The plungers
>>on both move freely, with no sticky feeling.
>> It is my understanding that when the pressure gets too high the
>>plunger moves in, opening the large hole on the side of the valve,
>>allowing the excess pressure to dump. I would suggest, as a test of a
>>faulty valve, plugging the valve hole with a bolt and then testing the
>>oil pressure. If it reads much lower then you know the valve is the
>>problem. If not, then it's somewhere else.
>>
>>Christopher
The spring rate will be measured in lbs/kg/gr per inch/cm/mm, not lbs per
psi.
The spring rate seems low beacuase the 2d area of the piston is also a first
order term, and since the piston is small, it doesnt need a huge spring to
back up the oil pressure.
If the valve is supposed to dump at 50 PSI, and the pistons area is
.100 sqr inch, it will need only 5 lbs of force to move the piston to the
dump hole in order to give a net dump pressure of 50 psi.
The spring rate is not so important, but the pressure that is required
to move the psiton to the edge of the dump hole is.
In this way, an ajustable backstop on the outside of the spring, allows
a variable force to be applied on the piston, and thus even the stock
spring can be used to generated higher PSI then the stock non-adjustable
oil pressure dump unit.
See T.J.s web page in the technical tips for more information on this mod.
Now for Steve Sage's problem,
I doubt this is a pressure dump valve related problem as this is the
opposite
mode of failure compared to the norm.
I think the best information yet on this subject comes from his statement
about the oil spraying from the filter after the engine was shut down.
I think this is key. This simply should not happen unless the engine is
running when you loosen the filter.
This suggests a very restrictive element inline with the oil supply.
This could be a bad filter, or could have something to to with the
OEM oil cooler base.
The oil cooler base has a pressure differencing valve in it that is supposed
to limit the amount of flow that goes through the cooler.
Perhaps it has malfuncioned and/or the cooler is somehow clogged.
I would remove the stock oil cooler for good measure and see if the problem
went away. Since the OEM cooler is not a great design anyhow, I would
install a full flow oil cooler, and never worry again.
$.02++
jarrid
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