concours
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Magnets.
Magnets are your friend.
scavenge pump flow rate
- Thread starter Tom Vachon
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Magnets are your friend.
Richard Tool
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You bet - got’em everywhere now including one suspended in the ES2 oil tank .
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OK, looks like the plots came thru so i’ll make some comments for them now.
Sorry, looks like they came thru in backwards order. The 3rd one shows oz/min vs pump and engine rpm at 66 to 68degF with 20W-50 for both the scavenge and lube pumps.
Note that just before 1000 pump rpm the scavenge pump flows less than the lube pump, despite its 60% greater capacity. And by 3150 engine rpm the difference is quite a bit and growing. But, as can be seen in the 2nd plot with oil temp up a bit to the 85-95 deg F range, the scavenge pump stays well ahead of the lube pump sll thru my test rpm range. The warmer oil decreases the oil viscosity a lot so the scavenge pump can draw up the sump oil thru the inlet passages without requiring as much suction/vacuum as is required for the more viscous room temp oil. Cooler temps and that 3/16” diameter passge from the sump really limits the scavenge pump by causing it to suck air in place of the thicker oil, thus cavitating with lots of visible aeration of the oil. Fortunately the oil warms up quickly after the engine fires.
The first plot shows lube oil pressure vs rpm. For reference the press relief valve on the bike opens from 45 to 55psi. Theres two pair of plots, each pair with a measured and a predicted line. The lower two were done with a 4’ length of 1/4” ID tube for outlet restriction and the upper pair was done with a 6’ length of 1/4” ID tube for restriction. I have no idea how soon the lube pressure is controlled by the relief valve, probably fairly early. But i was making these plots mainly to see how closely the formula could predict the measured values. As u can see its pretty close, esp considering my budget setup. And it verifies how sensitive the resistance to flow is to pipe diameter.
Bottom line for me is the lapping of the old pump improved it 40%, but the new pump was far better still. At cruising rpm it supplies lube oil at about one quart per minute and the saxvange pumpis well ahead of it. Would have liked to run bench testing at realistic running temps but thats just not worth the extra effort for me. Im happy with the room temp data and it easily shows the big difference between an old, a lapped, and a new pump.
btw, in the formula on the plot; p= psi, Q=flow rate, n = dynamic viscosity, L=pipe length, and r=pipe inner radius
Cheers, TomV
Sorry, looks like they came thru in backwards order. The 3rd one shows oz/min vs pump and engine rpm at 66 to 68degF with 20W-50 for both the scavenge and lube pumps.
Note that just before 1000 pump rpm the scavenge pump flows less than the lube pump, despite its 60% greater capacity. And by 3150 engine rpm the difference is quite a bit and growing. But, as can be seen in the 2nd plot with oil temp up a bit to the 85-95 deg F range, the scavenge pump stays well ahead of the lube pump sll thru my test rpm range. The warmer oil decreases the oil viscosity a lot so the scavenge pump can draw up the sump oil thru the inlet passages without requiring as much suction/vacuum as is required for the more viscous room temp oil. Cooler temps and that 3/16” diameter passge from the sump really limits the scavenge pump by causing it to suck air in place of the thicker oil, thus cavitating with lots of visible aeration of the oil. Fortunately the oil warms up quickly after the engine fires.
The first plot shows lube oil pressure vs rpm. For reference the press relief valve on the bike opens from 45 to 55psi. Theres two pair of plots, each pair with a measured and a predicted line. The lower two were done with a 4’ length of 1/4” ID tube for outlet restriction and the upper pair was done with a 6’ length of 1/4” ID tube for restriction. I have no idea how soon the lube pressure is controlled by the relief valve, probably fairly early. But i was making these plots mainly to see how closely the formula could predict the measured values. As u can see its pretty close, esp considering my budget setup. And it verifies how sensitive the resistance to flow is to pipe diameter.
Bottom line for me is the lapping of the old pump improved it 40%, but the new pump was far better still. At cruising rpm it supplies lube oil at about one quart per minute and the saxvange pumpis well ahead of it. Would have liked to run bench testing at realistic running temps but thats just not worth the extra effort for me. Im happy with the room temp data and it easily shows the big difference between an old, a lapped, and a new pump.
btw, in the formula on the plot; p= psi, Q=flow rate, n = dynamic viscosity, L=pipe length, and r=pipe inner radius
Cheers, TomV
Richard Tool
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Thanks Tom - all very enlightening.
Thanks for sharing all your oil pump testing data.
You made a comment above regarding higher temp testing and the challenges it presents, so wanted to inform that a very close approximation of the hi temp testing can in fact be performed at room temperature (RT). If you had the 20W-50 wt oil at full operating temp (100C/212F) it would have a viscosity in the range of 16-22 cSt. So, if one had a test fluid having a viscosity in this same range at RT, you could repeat your same tests at RT and simulate very closely how the hot 20W-50 motor oil would pump.
The table below shows SAE viscosity of several motor oil grades, thus provides a bit more info to quantify the differences between a range of SAE motor oil grades. The information source is linked below the table.
https://www.machinerylubrication.com/Read/23788/motor-oil-viscosity
I have prepared blends of common motor oil and WD-40 to create the low viscosity test fluids referred to above, as shown in the plot below. A blend containing ~ 40 wt% WD-40 in a 5W-20 motor oil would provide a test fluid having a viscosity very similar to 50 wt motor oil at 100C.
I’ve used the above described low viscosity test fluid (blend of motor oil and WD-40) several times to evaluate oil pumps from different marques. It is truly astounding how different the collected test streams may look when comparing a RT 20W-50 to a 20 cSt blend. More specifically, the RT motor oil tends to resemble a highly frothed beaker of yellow foam vs the almost bubble-free low viscosity test fluid. Regardless of the results one gets, this approach provides a realistic means of getting much closer to the actual oil pumping and scavenging rates of an engine at full operating temperature.
SteveA
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So I run a 1min 25 sec (2km) lap at an average 5500rpm, with 3 litres of oil in the tank!
How many laps does it take to run the whole tank of oil through the pumps?
Perhaps more seriously, I warm the engine at 2500rpm, how long does it take to warm the oil?, assuming the oil would need to pass through a minimum two or maybe three times?
How many laps does it take to run the whole tank of oil through the pumps?
Perhaps more seriously, I warm the engine at 2500rpm, how long does it take to warm the oil?, assuming the oil would need to pass through a minimum two or maybe three times?
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Great idea and info! I was thinking of trying a very low vis oil like auto trans fluid but this is much better. My only ques at this point is whether u hav to be concerned anout the WD evaporating quickly away from the blend.?
Temp and vis are so key to it all and im still waiting on the Castrol/BP people to give me the official vis of 20w-50 at 68 deg F. I used the vis for Mobile Special 20w-50 at 68degF for my calc cuz i could get a good estimate of it.
Have u bench tested a Norton Com pump with a blend?
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Well, i dont hav and cant find lube pump flow rate at eng rpm of 5500 and operating temp.
If i take a guess at extrapolating from my 30oz/min at 3150 rpm i would say about 45 oz/min. So thats 1.3 liter/ min so it would take about 1.6 laps to run 3 liters thru. thats just a guess. Somebody needs to give us the flow rate at 5500 rpm and at or near the correct temp.
As far as how long to warm up …thats a tougher ques than it appears, and i think u should just maesure the oil temp on the bike.
Great questions tho. Im interested to see whatmore of the replies will be.
SteveA
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If the bike had a traditional tank it would already have a temp sender in it. But it's harder to rig one on an oil in frame machine.
I have ordered temp gauges to fit under the spark plugs to monitor head temperature. It will tell me something! Then I will have to work out what that something means
Oil lubricates and oil cools. Oil flow rate may be more important to cooling than oil pressure, which is important to lubrication.
Back in the day Norton (works) and BSA (privateers) ran high volume pumps external to the cases or with visible external case mods. Classic race rules regulate against external modification of the type that Jim Comstock has implemented for his heavy duty road motors.
Seems to me it would be better to run the whole reservoir full of oil through the motor say every minute! As long as it was able to transfer significant heat out on the way (Coolers).
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Ive never raced one or had any gages on my Commando. But just looking at the basics, once the press relief vlv is set at a pressure of say 50 psi, it only lets the pump supply so much flow of a given oil viscosity. Could do more flow of thinner oil or less flow of thicker oil, but its a tradeoff. More flow gives more cooling, more viscous oil maintains oil films to prevent metal on metal in main brgs, piston skirts, etc.If the bike had a traditional tank it would already have a temp sender in it. But it's harder to rig one on an oil in frame machine.
I have ordered temp gauges to fit under the spark plugs to monitor head temperature. It will tell me something! Then I will have to work out what that something means
Oil lubricates and oil cools. Oil flow rate may be more important to cooling than oil pressure, which is important to lubrication.
Back in the day Norton (works) and BSA (privateers) ran high volume pumps external to the cases or with visible external case mods. Classic race rules regulate against external modification of the type that Jim Comstock has implemented for his heavy duty road motors.
Seems to me it would be better to run the whole reservoir full of oil through the motor say every minute! As long as it was able to transfer significant heat out on the way (Coolers).
So this leads me to ask if one could get by with shimming up the press relief vlv a bit to let it run at higher pressure and have more flow and or more viscosity.
Bear in mind that as soon as the relief vlv is controlling pressure it is bypassing some oil back to sump and keeping it from all the critical areas that need it.
But of course a bigger pump and a cooler would be best. But within the confines of an externally stock bike, for racing, i would shim the relief vlv and somehow determine the best weight of oil to run. Cheers, TomV
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The oil from the relief valve is sent back to the inlet side of the feed pump except the 850 Mk3 or pre-Mk3 fitted with a Mk3 (or modified pre-Mk3) timing cover.
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yea, unless u had the AMR mod.. But either way some of the oil doesnt go to lube vital parts but is just recirculated. But i dont know how much of the time and what percent of flow gets bypassed. Dont want to beat it to death but need to know more about it becuz u dont want to increase flow just to blow all the increase over the relief. Guys that hav press gages on their bikes should know, after oil warmed up, what rpm theyre over 45 psi oil press. Book says it opens at 45 psi.
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As I said "(or modified pre-Mk3) timing cover."
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Ah, yea, sorry. I didnt bother with my reading. glasses….
I would not be concerned about evaporation unless you expect to leave the solution out in the open with large surface area exposed for prolonged periods of time. If you are concerned, you could always pour a bit out in a small dia vessel that remained open, and watch it over time to see if a volume change occurs. Since there is such a large volume fraction of WD-40 present, if it were in fact evaporating, one would easily note the change in volume.
I have not tested with a Norton pump, but certainly hope that might be in your future activities. I'm quite certain that Jim Comstock would have answers to most of the questions posed here, however, he has not been posting for some time now, so we'll have to suffer along without his input.
BERT
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From my brief and hopefully enduring observation of this machine, the oil returning to the tank appears to have the viscosity of anything between a frothy latte and maple syrup, depending on temperature of the engine. The main thing is that the oil reaches the furthest points in the system as it is designed to do. It amazes me that a tiny oil pump like this can deliver like it does under sometimes harsh conditions. Thanks for your research efforts.
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zThe difference in viscosity between room temp and 100deg C is roughly a factor of 30!! So im even more curious how the blend would perform on my bench.
Thks for your suggestion and data, and im going shopping tomorrow for some Fleet and Farm Resolute 5w-20 and more WD40.
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WZ,
I want to get the same oil for my blend but my local Fleet and Farm has nothing called Resolute. They do have a full syn 5w-20 and a syn blend Premium 5w-20.
Could it be that Resolute was terminated? If so which should i use?
Thks, Tom
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