oil pressure relief system
- Thread starter 750nort
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750nort said:
It is to make sure that there is anough pressure to drive oil to where it needs to go. Sometime the spring gets weak then so does the oil pressure. There are shims available to go under the spring to boost its effectiveness and there fore boost oil pressure. If I am not mistaken, it think works against the return.
If the spring is over shimmed or the plunger is sticking then I guess it may over oil but I have not heard of that before.
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750nort said:
Basically, the OPRV is there to prevent the oil pressure from rising above a certain pre-set limit-especially when the engine oil is cold.
pvisseriii said:
The OPRV is on the feed side not return.
750nort said:
The usual place to connect a test gauge would be at the rocker feed connection in the timing cover.
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Why do you think the head is being over oiled?
There may be other reasons why the head is over oiling, such as the rocker spindles fitted with the flats facing in the wrong direction, a blocked oil drain gallery or problems with the inlet valve stem oil seals.
There may be other reasons why the head is over oiling, such as the rocker spindles fitted with the flats facing in the wrong direction, a blocked oil drain gallery or problems with the inlet valve stem oil seals.
pvisseriii said:
It's been my experience the only time the OPRV is in operation is at startup, until the oil gets to operating temperature. When the oil is cold, oil pressure from the pump can be extremely high. The OPRV then dumps off the excess pressure. As L.A.B. pointed out, it only limits oil pressure, it will not increase the actual pressure the pump is making. At operating temperature the stock Norton oil pump, as a rule of thumb, puts out ≈10 psi per 1,000 rpm. Shimming the OPRV will NOT increase that pressure. Hot oil pressure at idle can be very low, less than 5 psi.
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Dave, why would a straight 50 weight oil return to the tank any better than a lighter weight oil, as you seem to be saying with your comparison statement?
Also, since people say that most engine "damage" occurs at startup, and since a straight 50 weight flows and gets to moving parts initially more slowly than a lighter weight oil, why do you choose a heavier oil?
Would not a 20-50 be the best choice, the 20 for cold start and better flow, and still the 50 for running hot?
Not doubting or questioning you, just would like to hear your rationale for a straight 50.
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yeah an oil thread! (your to late dave!)!:shock:
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DogT said:
Both the feed and scavenge pumps are positive displacement. In theory, whether you start cold with 50wt or 20/50wt should not make a significant difference in terms of what reports to the crankcase, but I see the differences being that with a more viscous oil the volume reporting to the journals is generally less and more goes to by pass. This represents reduced flow to the journals.
My hunch is that the more viscous oil is slower at being picked up and hangs longer in the crankcase (on surfaces) delaying pick up by the scavenge pump.
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Be aware that Norton issued a notice for the reasons they so soon stopped installing pressure gauges. Comnoz or me needs to come up with a hand crank adjustable pressure relief to suit the various oils and riding conditions : ) I'm putting a gauge on Peel of course to see how thin of oil she can still make pressure with. Muliti grade should help lower initial cold pressure and still show some pressure on hwy. The neatest gauges I've seen run up through the steering stem with gauge front and center.
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I put a oil pressure sending unit on my 850 and hooked it up to the red idiot light in the head light. The light goes out in one kick every time. I run 50wt. oil. I always felt that I would rather know I have oil pressure than knowing my alt. is charging! After it's up to running temp and idling I've never had the light ever come on or flicker it just gives me peace of mind. The worst can happen without that stupid Warning light Assimillator is a dead battery and have to call for a pickup. But if your oil pressure fails your done also but it's very costly.
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