Oil pressure gauge off the dial

Thanks.

dynodave said:

Regular oil pump flow is out the front where the crankshaft lines up. Oil pump flow is measured on the VA meter on the right. There are no other outlets from the timing cover gallery except the Lab 0-100PSI gauge on top.
This was a bit of engineering and machining to make this set up but it's not rocket science either.

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How did you simulate the consumption rate of the crankshaft and valve gear as under normal circumstances the OPRV would never have to cope with full output from the oil pump?

L.A.B. said:

Thanks.
How did you simulate the consumption rate of the crankshaft and valve gear as under normal circumstances the OPRV would never have to cope with full output from the oil pump?

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If you see the black knob on the crank output outlet, that is a fine needle valve where, at any rpm, I can restrict the flow rate on the flow meter and see the back pressure on the gauge. If I set, typically 40 psi, then the tightness of the pump is indicated by the flow rate. A garbage pump has significant internal cavitation loss, there is much less for flow to the engine.
Having tested two NEW pumps it is quite eye opening to see how bad worn out pumps can be...even if the shop manual end clearance job is done. The other three wear paths are not addressed...

I have seen a good percentage that are quite good and would reuse then in a fresh engine. I also have a box of garbage pumps.
So far I don't sell them on ebay.

Besides the needle valve, you might see the shut off valve. It is mainly used to check the OPV function for cracking pressure and pressure moderation above cracking pressure.

When doing a oil pump test alone, I shut off the OPV circuit by pulling the flowmeter connector off the opv outlet.

dynodave said:

If you see the black knob on the crank output outlet, that is a fine needle valve where, at any rpm, I can restrict the flow rate on the flow meter and see the back pressure on the gauge. If I set, typically 40 psi, then the tightness of the pump is indicated by the flow rate. A garbage pump has significant internal cavitation loss, there is much less for flow to the engine.
Having tested two NEW pumps it is quite eye opening to see how bad worn out pumps can be...even if the shop manual end clearance job is done. The other three wear paths are not addressed...
I have seen a good percentage that are quite good and would reuse then in a fresh engine. I also have a box of garbage pumps.
So far I don't sell them on ebay.

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Yes, but what I was asking is that unless the 'loss' rate through the crankshaft and valve gear is taken into consideration then the oil pressure readings taken are likely to be abnormally high.

If, for instance, the total output of the oil pump is simply directed to the OPRV with none going to the crankshaft and valve gear then under those conditions readings can reach "160psi cold" if the OPRV isn't capable of venting that quantity of cold oil.

Totally with you...if you notice the red color, it is ATF. The fluid has to be about the same centistoke rate of hot oil or I would have to put a engine oil heater and controller in the oil tank to get realistic pressure and flow rate simulation. ATF is much more user friendly. I could not see my fingers constantly working in a 160-180F oil environment. AND I already knew that 50W will make 160+psi at 15deg F when you blip the throttle...LOL Hard to start too!
I still have to be careful with the ATF and can easily peg the 100psi gauge with unnatural valve setting and engine/pump speeds.

Is that gauge set up one of John's? Why dont you email him and ask if he can help, he seems like a decent guy.
But agree with the banjo approach. All my OP gauge setups use either that
or an AN-3 fitting and hose on both ends.

dynodave said:

I still have to be careful with the ATF and can easily peg the 100psi gauge with unnatural valve setting and engine/pump speeds.

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Unnatural valve setting was my point that the flow rate from the crankshaft and valve gear at a particular RPM needs to be known and the valve set accordingly to bleed off that quantity of oil to get an accurate pressure reading hot or cold, thick or thin oil.

If that isn't done then as I see it, the pressure readings are not being taken under normal operating conditions.

Edit:

dynodave said:

AND I already knew that 50W will make 160+psi at 15deg F when you blip the throttle...LOL Hard to start too!

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I've done similar using SAE 50 after lapping the pump at around 10 deg. C (50F) but didn't get anything like the same result.

L.A.B. said:

but didn't get anything like the same result.

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same result AS ???

For a whole series of pump flow charts based on temperatures and viscosity and RPM would be thick like a dictonary.
I would love to see the book report that the norton twin pump gets...LOL

A club guy had big bucks engine NHT hybrid rebuilds ($3000) done by a cycle repair shop where the old original pump was reused. The engine lasted less than 400 miles then the rod bearing/crankshaft died. I tested that pump and it yielded very poor performance in a simple comparison to a new pump.
Two more club guys were also doing their atlas engines over and had me test their pumps BEFORE the engines went back together. Again measurably low flow at 40psi. something like 30% flow of a new pump. They bought new pumps.

I even own one lightly used pump that tested better than a new AN pump.
75-90 % flow compared to new is common enough and is often considered OK to reuse.
I've had my test machine for maybe 10 years and have learned a lot testing dozens of both 3 and 6 start pumps. However I have no desire to sell a testing service.
My testing standard is now 40psi with ATF at 68-70 deg F. Even after running the machine for a while, a 5 deg fluid temp rise affects the flow measurement. So viscosity going from 15 deg F up to 50 deg F is huge (300%or more) and up to 160-180 must be astronomical and is way above the capability of my machine or my academic interest.

Great info Dave. Thanks

Is not the question then "Is it pressure or flow that matters most?"

dynodave said:

same result AS ???

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As in, the oil pressure reading increased to the point where the OPRV kicked in sharply and higher revs hardly increased the pressure beyond that, making no more than about 60-65 psi, nowhere near "160 psi", which hopefully, can be seen in the rather poor quality video I took at the time.

dynodave said:

For a whole series of pump flow charts based on temperatures and viscosity and RPM would be thick like a dictonary.

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dynodave said:

I would love to see the book report that the norton twin pump gets...LOL

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Maybe so, but as I see it, unless the bleed valve is set to a known rate of crank and valve gear drainage at a particular RPM then psi figures seem meaningless as it's not testing under normal operating conditions. If, for instance, the 'bleed' valve is closed then all the oil has to pass through the OPRV which, under normal circumstances wouldn't happen as I'm sure the majority would flow out of the big ends regardless of viscosity or temperature so the pressure readings would then be abnormally high.

Classic Cycle Repair said:

Yes, I have an idea as to why that has happened. In respect of the gauge not returning, there is a (somewhat unlikely) possibility of a blockage not allowing pressure to release, and as you mentioned the gauge may have been damaged, so is merely "jammed".
As far as the gauge hitting 100 psi, it may be as simple as you have more than 100 psi of oil pressure (on cold start-up). With thick oil, cool temperatures, a new (or at least top condition) oil pump, and plenty of shims in the OPRV, that pressure is obtainable, especially if the rpm are not kept in check.

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Where is your shop? I may visit if I am close..tnx

Onder said:

Is not the question then "Is it pressure or flow that matters most?"

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Unfortunately the physics of engines is not single dimensioned A or B, but their realizing their interaction is when understanding happens.
The volume of flow is what lubes and cools the rod bearings or prevents rocker shaft galling. If the machined tolerance is to big there may be flow but the pump can't deliver enough to cool the rod bearings. As the bearings deform/melt the material is squeezed out the side of the rod and will close the rod/crank gap. The pressure goes way up but there is little to no flow/no cooling. The driver thinks the pressure was "great" until the knocking started. Finally the rod lets go if you don't shut it down first.

I look as the OPV as the crank seal saver. When in mid 90's I pit crewed for a friend, his commando inverted the crank end seal on the straight at Mosport-Canada. Luckily he saw it on the oil pressure gauge.

When I was 20 and had my 1970 roadster heading north of Utica NY going toward Watertown, laid down on the tank and cranked it to 115 "indicated". Satisfied, throttle shut down and I sat up for the air brake and at 105 "indicated" it went POW.
Engine blew and locked up rear wheel. No oil pressure gauge but I'm fairly sure it was a oil starvation from the "S" oil tank possibly a failure to scavenge the sump. I'll never know for sure. I was eventually able to grab the clutch then the speedo popped back up to 55mph. 1/2 the tire tread and 3 sets of cords were gone! thump thump thump.
You and I both know "indicated" is not true speed.

L.A.B. said:

As in, the oil pressure reading increased to the point where the OPRV kicked in sharply and higher revs hardly increased the pressure beyond that, making no more than about 60-65 psi, nowhere near "160 psi", which hopefully, can be seen in the rather poor quality video I took at the time.

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could not see video?

google motor oil viscosity and look at the 20/50 viscosity at 160f/70c, 50f/10c and 15f/-9c. You probably wont find 50W.
It is HUGE the difference in viscosity at 15f. The crank/rods and rockers AND including OPV and the passages can no way vent all the flow if you raise the RPMs. The total clearance is fixed for the engine machine parts despite it is rotating. While the pump gives an ever increasing flow. The OPV tries to dump the excess pressure/flow but with the abnormal cold high viscosity it can not cope and the pressure skyrockets. Put winter oil and it returns to vent normally. When the oil is up to normal running temp the OPV is not activated. Idle will often yield sub 5psi readings. At moderate back road speeds 40psi is very common. Highway blasts heat the oil/lower the viscosity therefore the pressure typically does not go up much, if at all despite the higher RPMs .

dynodave said:

could not see video?

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Try it now.

dynodave said:

google motor oil viscosity and look at the 20/50 viscosity at 160f/70c, 50f/10c and 15f/-9c. You probably wont find 50W.

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I wouldn't expect to find SAE 50 as it isn't 'winter' oil at least not for a Commando so starting one up at 15 deg. f with what is a 'summer' oil is outside what could be considered normal operating conditions.

dynodave said:

The OPV tries to dump the excess pressure/flow but with the abnormal cold high viscosity it can not cope and the pressure skyrockets. Put winter oil and it returns to vent normally.

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Precisely, because with a winter oil the system is once again operating under normal conditions.

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