So for the first few moments of a Holden six-cylinder engine running, should the filter bypass valve (in the pump) be open? So should oil theoretically be bypassing the filter until the galleries are adequately primed?
202 delayed oil pressure on startup
Started by
_mick74lh_
, Aug 10 2012 04:15 PM
51 replies to this topic
#27
_torbirdie_
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Posted 14 August 2012 - 10:56 PM
So for the first few moments of a Holden six-cylinder engine running, should the filter bypass valve (in the pump) be open? So should oil theoretically be bypassing the filter until the galleries are adequately primed?
as far as I understand the bypass on the oil pump is to protect the pump.......and it simply passes the oil back to the sump, not to the top of the motor.
S pack claims the filters for Holden sixes dont have the relief valve, he maybe right, but whether any aftermarket filters that fit the six dont have them? dont know.
The oil pump bypass would trigger only at high rpm with cold oil or at even lower rpm if you are using something heavier than 20W, at idle unlikely. Either way, it would show up on the oil pressure gauge as being high. Also as afaik the pump bypass is not really a bypass, just a relief and still passes oil through the filter to the top of the motor even when the relief is triggered
#28
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Posted 14 August 2012 - 11:02 PM
so your the prick stealing all our filters out of the sea containersI used to work for Donaldson filters lol.
For most of our applications, as long as it has an ADV, it will be fine, we dont need (nor really want) the micron filtration that some of those higher specced filters provide.
p.s. I ran donaldson filters for a while.... they are great when they are freeeeee!
#29
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Posted 14 August 2012 - 11:45 PM
as far as I understand the bypass on the oil pump is to protect the pump.......and it simply passes the oil back to the sump, not to the top of the motor.
S pack claims the filters for Holden sixes dont have the relief valve, he maybe right, but whether any aftermarket filters that fit the six dont have them? dont know.
The oil pump bypass would trigger only at high rpm with cold oil or at even lower rpm if you are using something heavier than 20W, at idle unlikely. Either way, it would show up on the oil pressure gauge as being high. Also as afaik the pump bypass is not really a bypass, just a relief and still passes oil through the filter to the top of the motor even when the relief is triggered
The three brands of filters that I have only ever used on my engines are AC Delco, Ryco and Valvoline and none of them have built in bypass valves.
The Holden oil pumps have two bypass valves.
One is the filter bypass valve which, as the name suggests, bypasses the filter if the filter is unable to flow sufficient quantities of oil to the engine, ie: a clogged filter or the oil is too thick to pass through the filter fast enough.
In both cases the filter bypass valve will open if the pressure on the pump side of the filter is 9 - 11 psi higher than the gallery side of the filter. This is to protect the engine not the oil pump.
The pump bypass valve (pressure relief valve is better description) is to limit the maximum pressure the pump can produce. Maximum pressure of 30 to 45 psi (hot) is reached @ 1500rpm but it has been common practice with performance engines to shim the spring to increase the maximum pressure up to 60psi (hot).
If the oil pump didn't have this pressure relief valve then the oil pressure would keep increasing as the revs increase until something fails, most likely the oil filter.
#31
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Posted 15 August 2012 - 08:14 PM
Cool, im not insane.
Are you really really sure about that Bomber? 
#32
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Posted 15 August 2012 - 09:02 PM
No, come to think of it, no im not at all sure.
#33
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Posted 15 August 2012 - 10:51 PM
Hello most of what you all say is correct. Some is assumption and very little is based in hard fact.
Take a filter apart you will notice that the filter medium is held in position by a spring under the medium. This is the filter bypass not the pump bypass (The manual must be wrong). The anti dran back valve is a one way valve for use when the filter is positioned at odd angles other than vertically up. Holden 6s sideways, Chrysler Fireball engines upside down.When the filter medium is blocked (or the oil is cold and has a high viscosity) and wont pass through it there is a build up of pressure ( resistance to flow). This pressure overcomes the spring pressure by force and dislocates the filter from the pump outlet, the spring is compressed and the oil bypass's the medium and flows into the sump. There is also a bypass in the pump to protect the pump. When the engine is subjected to an increase in revs (acceleration) the oil filter cannot pass the oil quantity so it bypass's into the sump. If there was no bypass in the filter, under pressure the filter would explode or come off the engine, The pump would most likely shear a shaft unless its bypass can handle the flow. Have you ever worked out how much power is needed to drive a n oil pump?. The pump supplies fluid at x liters per minute at x revs the filter can only filter x liters per minute regardless of the pumps capacity and revs. Racers run two or more filters to get the filtering capacity or don't run any because the engine only has to last the race duration.Car manufacturers (Holden) have to produce engines for the mass's who would rather fit a chrome coffee can exhaust tip than give the engine an oil change (sarcasm). People who brag that they get X kilometers from their filters don't know for how long the filter has been bypassing and not filtering (Put some flow gauges on them like some trucks have on their air filters). Some old filters are full of jelly cut one open. The oil pressure sensor can only sense pressure at the point it is located. Oil pressure does not indicate oil flow in fact it indicates the opposite. Easily proved measure the pressure in a tyre there is no flow except for what travels into the gauge. Flow is always accompanied by a drop in pressure (Physics). I am happy to pass on any info I have to anyone that wants to learn. I am frequently wrong and have no trouble learning from anyone or anything.But some of you have a problem here. If you annoy the people that know how, are you going to learn?. The people that know will just go away.That is what I am doing. Change the filter and see what happens. Set up a test bench and measure the bypass rates that's what I did. I can only make comments on the information given and then take a punt.This is my last posting I have had fun but will move on. I think the sites great for what's its worth. Learning how a car engine works is easy ( suck squeeze bang blow) Understanding how it works No suck (atmospheric pressure charges the cylinder) suddenly changes the parameters of flow dynamics porting etc, Adding in air velocity and density now changes the fuel air ratios, differing oxygen contents (Rainy day Hot Day) affects the fuel that has differing calorific quantities and burn times. How deep do you want to go.
I am off and may see you in my rear vision mirror one day.
Take a filter apart you will notice that the filter medium is held in position by a spring under the medium. This is the filter bypass not the pump bypass (The manual must be wrong). The anti dran back valve is a one way valve for use when the filter is positioned at odd angles other than vertically up. Holden 6s sideways, Chrysler Fireball engines upside down.When the filter medium is blocked (or the oil is cold and has a high viscosity) and wont pass through it there is a build up of pressure ( resistance to flow). This pressure overcomes the spring pressure by force and dislocates the filter from the pump outlet, the spring is compressed and the oil bypass's the medium and flows into the sump. There is also a bypass in the pump to protect the pump. When the engine is subjected to an increase in revs (acceleration) the oil filter cannot pass the oil quantity so it bypass's into the sump. If there was no bypass in the filter, under pressure the filter would explode or come off the engine, The pump would most likely shear a shaft unless its bypass can handle the flow. Have you ever worked out how much power is needed to drive a n oil pump?. The pump supplies fluid at x liters per minute at x revs the filter can only filter x liters per minute regardless of the pumps capacity and revs. Racers run two or more filters to get the filtering capacity or don't run any because the engine only has to last the race duration.Car manufacturers (Holden) have to produce engines for the mass's who would rather fit a chrome coffee can exhaust tip than give the engine an oil change (sarcasm). People who brag that they get X kilometers from their filters don't know for how long the filter has been bypassing and not filtering (Put some flow gauges on them like some trucks have on their air filters). Some old filters are full of jelly cut one open. The oil pressure sensor can only sense pressure at the point it is located. Oil pressure does not indicate oil flow in fact it indicates the opposite. Easily proved measure the pressure in a tyre there is no flow except for what travels into the gauge. Flow is always accompanied by a drop in pressure (Physics). I am happy to pass on any info I have to anyone that wants to learn. I am frequently wrong and have no trouble learning from anyone or anything.But some of you have a problem here. If you annoy the people that know how, are you going to learn?. The people that know will just go away.That is what I am doing. Change the filter and see what happens. Set up a test bench and measure the bypass rates that's what I did. I can only make comments on the information given and then take a punt.This is my last posting I have had fun but will move on. I think the sites great for what's its worth. Learning how a car engine works is easy ( suck squeeze bang blow) Understanding how it works No suck (atmospheric pressure charges the cylinder) suddenly changes the parameters of flow dynamics porting etc, Adding in air velocity and density now changes the fuel air ratios, differing oxygen contents (Rainy day Hot Day) affects the fuel that has differing calorific quantities and burn times. How deep do you want to go.
I am off and may see you in my rear vision mirror one day.
#34
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Posted 15 August 2012 - 11:08 PM
The workshop manuals aren't wrong Gubba. Pull a Holden 6 or 8cyl oil pump to pieces and see for yourself.
Oh and by the way, if the filter bypass valve dumps the oil back into the sump and not the oil galleries your engine would be f*&%d in no time.
See ya
Cheers
Dave.
Oh and by the way, if the filter bypass valve dumps the oil back into the sump and not the oil galleries your engine would be f*&%d in no time.
See ya
Cheers
Dave.
#35
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Posted 16 August 2012 - 07:33 AM
Hello most of what you all say is correct. Some is assumption and very little is based in hard fact.
........ How deep do you want to go.
I am off and may see you in my rear vision mirror one day.
The workshop manuals aren't wrong Gubba. Pull a Holden 6 or 8cyl oil pump to pieces and see for yourself.
Oh and by the way, if the filter bypass valve dumps the oil back into the sump and not the oil galleries your engine would be f*&%d in no time.
See ya
Cheers
Dave.
All very interesting guys but none of the chest beating ^ would seem to address the problem the op is having, as the OP has reported the rattling is accompanied by low oil pressure readings, not a sign that the filter is blocked/restrictive or bypass pressures have been reached.
Edited by torbirdie, 16 August 2012 - 07:36 AM.
#36
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Posted 16 August 2012 - 11:06 AM
All very interesting guys but none of the chest beating ^ would seem to address the problem the op is having, as the OP has reported the rattling is accompanied by low oil pressure readings, not a sign that the filter is blocked/restrictive or bypass pressures have been reached.
^^^So true. I'll have a look and see if I can find it but in a nutshell I remember reading in a GMH Dealer Service Letter regarding customer concern/complaint about noisy tappets at initial engine start up.
From memory GMH advised Dealers it isn't abnormal for an engine to emit a tapping noise for the 1st few seconds at initial start up until the hydraulic lifters that have bled down pump up again.
This in itself may not be the OP's problem however if he is using anti pump up lifters it might explain why the valve train is emitting excessive noise and why the oil pressure is a bit slow to come up.
Also using a thinner grade of engine oil will help the oil pressure to come up faster, esp in really cold climates.
#37
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Posted 16 August 2012 - 12:37 PM
Even my Vt commodore is rattly for the first couple seconds on startup (if left for a day or so without starting)
Short of something like an accumulator, there isnt really much of a way to ensure instant feed and flow through the entire engine.
Short of something like an accumulator, there isnt really much of a way to ensure instant feed and flow through the entire engine.
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Posted 16 August 2012 - 01:51 PM
Found it!!!
#39
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Posted 16 August 2012 - 10:05 PM
Thanks for posting all this information guys. Interesting debate here too.
For the record, the lifters in my engine are standard hydraulic (not anti-pump). I've been running just Castrol 20W 50 in the engine. As the engine has only done about 25,000km since I honed it, put in new rings and bottom end bearings, and new valve stem seals, would a 15W 40 grade of oil possibly be suitable? My concern with going too fine would just be burning oil.
The problem I'm having sounds exactly like the 'normal' scenario described in the GMH tech note posted by Dave.
As the oil is well due for a change, I'll replace the oil and filter this weekend, and see if any difference is made. If not then I'll just live with it a while longer. I just need to decide on a grade of oil first. For interests sake I plan to keep the filter and cut it open for a look when I get the chance.
For the record, the lifters in my engine are standard hydraulic (not anti-pump). I've been running just Castrol 20W 50 in the engine. As the engine has only done about 25,000km since I honed it, put in new rings and bottom end bearings, and new valve stem seals, would a 15W 40 grade of oil possibly be suitable? My concern with going too fine would just be burning oil.
The problem I'm having sounds exactly like the 'normal' scenario described in the GMH tech note posted by Dave.
As the oil is well due for a change, I'll replace the oil and filter this weekend, and see if any difference is made. If not then I'll just live with it a while longer. I just need to decide on a grade of oil first. For interests sake I plan to keep the filter and cut it open for a look when I get the chance.
#40
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Posted 16 August 2012 - 11:03 PM
GMH recommended SAE viscosity grades of oil for use in atmospheric temperatures above 0 deg C are:- 20W, 20-30, 20W-40 and 30-40.
For sustained high speed driving they recommend using any of the aforementioned grades except the 20W.
Note: Information sourced from the LJ Torana Owner Manual.
The 15W 40 should be ok but read the label on the pack to see if it is suitable to use where the aforementioned grades are recommended.
For sustained high speed driving they recommend using any of the aforementioned grades except the 20W.
Note: Information sourced from the LJ Torana Owner Manual.
The 15W 40 should be ok but read the label on the pack to see if it is suitable to use where the aforementioned grades are recommended.
#41
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Posted 16 August 2012 - 11:14 PM
Well..........there it is in black and white Mick?.................................Told ya!
I reckon if you dig far enough there would even be a part number for it?
I reckon if you dig far enough there would even be a part number for it?
#42
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Posted 16 August 2012 - 11:48 PM
Read your mind Mick.
I was a bit bored today, works pretty patchy ATM so I took the wiss snips to a Ryco Z30 I had draining out from a recent oil change on the LJ.
Yeah I know I really need to get a life, LOL.
Anyways, if Grubbydog or Maddog or whatever he calls himself could possibly find it in his big heart to pop in just one more time and have a look at the following pics and tell me which part of the filter is the bypass valve I'd greatly appreciate it, 'cause I can't find the f%&#ing thing. Maybe it fell out onto the ground as I was cutting it open and I didn't notice?
I found the anti drain back valve easy enough, it's the red rubber washer/seal that covers the filter side of the oil inlet holes.
I was a bit bored today, works pretty patchy ATM so I took the wiss snips to a Ryco Z30 I had draining out from a recent oil change on the LJ.
Yeah I know I really need to get a life, LOL.
Anyways, if Grubbydog or Maddog or whatever he calls himself could possibly find it in his big heart to pop in just one more time and have a look at the following pics and tell me which part of the filter is the bypass valve I'd greatly appreciate it, 'cause I can't find the f%&#ing thing. Maybe it fell out onto the ground as I was cutting it open and I didn't notice?
I found the anti drain back valve easy enough, it's the red rubber washer/seal that covers the filter side of the oil inlet holes.
Edited by S pack, 16 August 2012 - 11:50 PM.
#43
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Posted 17 August 2012 - 12:52 PM
Well..........there it is in black and white Mick?.................................Told ya!
I reckon if you dig far enough there would even be a part number for it?
Haha Rodomo all you told me was not to worry about it!
Thanks for posting that Dave. Nice one!
#44
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Posted 17 August 2012 - 02:31 PM
Dave, I think what our puppy friend was trying to say, was that the filter media, under high pressure (when the media cannot filter the volume or deal with the pressure)
The media is pushed backwards in the filter housing (the rate and distance determined by the spring rate and the pressure its facing)
The oil can then "bypass" the filter by running direcly under the face of the filter media.
So not a "valve" as such, but definitely a safety mechanism (although I believe most springs would be too heavy to act as a failsafe, most cars would munch their engines before it did any good I reckon)
The media is pushed backwards in the filter housing (the rate and distance determined by the spring rate and the pressure its facing)
The oil can then "bypass" the filter by running direcly under the face of the filter media.
So not a "valve" as such, but definitely a safety mechanism (although I believe most springs would be too heavy to act as a failsafe, most cars would munch their engines before it did any good I reckon)
#45
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Posted 17 August 2012 - 03:54 PM
Dave, I think what our puppy friend was trying to say, was that the filter media, under high pressure (when the media cannot filter the volume or deal with the pressure)
The media is pushed backwards in the filter housing (the rate and distance determined by the spring rate and the pressure its facing)
The oil can then "bypass" the filter by running direcly under the face of the filter media.
So not a "valve" as such, but definitely a safety mechanism (although I believe most springs would be too heavy to act as a failsafe, most cars would munch their engines before it did any good I reckon)
For the spring to function like that would require the oil to enter through the centre and outwards through the media - in other words backwards flow. Because the spring end has a slightly larger effective area than the outlet end (as result of the outlet hole in the middle) the inlet oil pressure adds to the force of the spring, it doesn't detract from it. No matter how big the pressure drop becomes it ain't gonna lift against the spring, it'll just push harder against the seal. You can usually see the little bypass valve in the bottom through the centre hole of engine oil filters with built in bypass.
#46
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Posted 17 August 2012 - 04:30 PM
For the spring to function like that would require the oil to enter through the centre and outwards through the media - in other words backwards flow. Because the spring end has a slightly larger effective area than the outlet end (as result of the outlet hole in the middle) the inlet oil pressure adds to the force of the spring, it doesn't detract from it. No matter how big the pressure drop becomes it ain't gonna lift against the spring, it'll just push harder against the seal. You can usually see the little bypass valve in the bottom through the centre hole of engine oil filters with built in bypass.
^^^ Spot on John. You beat me to it.
#47
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Posted 17 August 2012 - 07:47 PM
You also beat me to it, i was gonna cut one open tomorrow.
Cheers.
Cheers.
#48
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Posted 22 August 2012 - 08:52 PM
Don't want to mozz things, but I changed the oil and filter on the weekend and it seems to have fixed the problem. The oil pressure comes up straight away now and doesn't clack like it was.
I replaced the oil with the same Castrol 20W 50 and Ryco Z30 filter. I half expected the old oil filter to be missing the ADV but upon inspection, it was in place as it should be.
I'm stoked that the problem has gone but mystified as to why. The old oil was well due for a change - dunno if that could have affected its viscosity when cold????
The old filter is sitting there draining out waiting for when I get a chance to cut it open and have a look. Cheers to Dave for posting those photos but I'm still curious to see if there were any defects in my old filter.
I replaced the oil with the same Castrol 20W 50 and Ryco Z30 filter. I half expected the old oil filter to be missing the ADV but upon inspection, it was in place as it should be.
I'm stoked that the problem has gone but mystified as to why. The old oil was well due for a change - dunno if that could have affected its viscosity when cold????
The old filter is sitting there draining out waiting for when I get a chance to cut it open and have a look. Cheers to Dave for posting those photos but I'm still curious to see if there were any defects in my old filter.
#49
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Posted 22 August 2012 - 10:15 PM
Send a link to this thread to Scully and Mulder......................the truth is out there................... 
#50
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Posted 26 August 2012 - 10:19 AM
Mick.
Thats great to see its fixed.
Just like my filter.. ( Reply about post No 3) Changed the filter and all back to ok. I can't remember if the "tappety" noise started to apear slowly or not.
Unfortunatly I threw my filter out before having the thought to open it & check it out . Let us know how yours looked & maybe some Pic's ??
Paul.
Thats great to see its fixed.
Just like my filter.. ( Reply about post No 3) Changed the filter and all back to ok. I can't remember if the "tappety" noise started to apear slowly or not.
Unfortunatly I threw my filter out before having the thought to open it & check it out . Let us know how yours looked & maybe some Pic's ??
Paul.
Edited by Red GTR, 26 August 2012 - 10:31 AM.
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