Building oil pressure
07-01-2012, 03:22 PM
#1
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Building oil pressure
I have a problem building oil pressure on cold starts which I would like to get you guys thoughts and opinions on. Basically I am running Rotella 5w40 and a Wix filter suggested by Hustler, and I have a 16" SS line that runs from my oil sender location to the firewall and there it T's off to my oil pressure sender and my soon to be oil feed line for my turbo. It takes a good 20 seconds to build pressure. My HLA's rattle like ---- until pressure builds and once it does my gauge starts reading. My Wix filter has the anti-drain valve, is my oil running back down from my SS line causing it to take awhile? or does this seem like a oil pump issue. I have to idle the car around 1200rpms til it builds pressure, then it idles around 850rpm with 20psi.
GOPR0021 - YouTube
GOPR0021 - YouTube
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07-01-2012, 03:40 PM
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They are stock gears, I disassembled and inspected everything when I rebuilt it and everything seemed fine. I don't remember having this problem before when I had mobile 5w20 and my stock sender. My gauge in the cluster went out so I got an aftermarket gauge. I put in the SS line, new oil and gauge in all at the same time so I don't know what it could be.
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07-01-2012, 09:23 PM
#4
Is the bypass working on the filter? You have no way of knowing that. I think the cheap bet would be to swap the filter and see if that fixes it. Your oil pressure is all fine when the car is hot right? like above 25 at idle, cruising at like a good bit above the 30 mark. The only thing it could be in that case would be a restriction at some point between the pump and the pressure sender, and it basically blocks flow when the oil is at high viscosity then the oil can flow once it heats up. It cant flow through the filter media when its cold so if the bypass valve is stuck closed it wont flow through until it warms up.
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07-01-2012, 10:08 PM
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Is the bypass working on the filter? You have no way of knowing that. I think the cheap bet would be to swap the filter and see if that fixes it. Your oil pressure is all fine when the car is hot right? like above 25 at idle, cruising at like a good bit above the 30 mark. The only thing it could be in that case would be a restriction at some point between the pump and the pressure sender, and it basically blocks flow when the oil is at high viscosity then the oil can flow once it heats up. It cant flow through the filter media when its cold so if the bypass valve is stuck closed it wont flow through until it warms up.
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07-02-2012, 05:15 AM
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That is a major problem. I would suspect a bad oil filter or a stuck relief valve. Judging from the pressure you make at cold idle, I would go with the stuck relief valve. If you've been using the motor like that for a while, you're probably due for bearings very soon.
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07-02-2012, 08:12 AM
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With a stuck relief valve I wouldn't be making any oil pressure at all correct? Why would it take 20 or so seconds to start building everytime it is cold started? maybe when its warmed up a bit it gets unstuck?
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07-02-2012, 08:32 AM
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Watch the video, the engine sound changes when the gauge spikes up.
That is a major problem. I would suspect a bad oil filter or a stuck relief valve. Judging from the pressure you make at cold idle, I would go with the stuck relief valve. If you've been using the motor like that for a while, you're probably due for bearings very soon.
That is a major problem. I would suspect a bad oil filter or a stuck relief valve. Judging from the pressure you make at cold idle, I would go with the stuck relief valve. If you've been using the motor like that for a while, you're probably due for bearings very soon.
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07-02-2012, 08:48 AM
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Well i guess i need to rid of this ---- gauge first an see with a mechanical gauge if i'm getting pressure on startup. If not screw it, run it til it blows and build the 1.8 in the shop with better oil pump gears and forged internals. Once it starts reading it runs fine, i always thought if the relief valve was stuck open or closed i wouldnt be getting any pressure at all.
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07-02-2012, 08:59 AM
#12
No if its stuck open you just end up not sending all the oil through the filter. If its stuck closed you just send practically no oil through the engine until the oil is hot enough to go through the filter. What oil gauge are you using? I know pro-sport doesnt take 20 seconds to read properly its more like 5. But to check it for cheap just buy a normal gauge at teh hardware store and have a friend crank it over.
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07-02-2012, 09:13 AM
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I have vdo gauges, my water crapped out so now i have an AutoMeter i guess i should have went Autometer to begin with. We have a mechanical gauge I am going to borrow from work, i may be able to even do it up here since we are so slow today. Just strange that once I swapped oil, filter and that SS line it started acting up
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07-02-2012, 10:23 AM
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Did you at any time separate the pickup tube from the oil pump?
It sounds like you are drawing air on startup until the pump draws enough suction to fully prime itself. Once primed, it does a far better job maintaining suction due to the oil better filling the clearances between and around the gears. Excessive clearance between the gears and the housing could conceivably cause this as well.
I don't buy the stuck relief valve theory because the "relieved" oil goes to the pan and doesn't just bypass the filter, but bypasses everything. A relief valve stuck partially open would make the most pressure it could make at cold start and steadily decline as the oil thinned, possibly to zero.
If the oil filter's internal bypass was stuck open oil pressure would still be reasonably high when cold, depending on bearing tolerances and other pressure lubricated tolerances, and would taper off as the oil heated and thinned. Having changed the filter to no effect would have eliminated it as a focus even if the symptomology was pointing to it, which it was not.
Was there any carbon, varnish, or golden to reddish-brown residue coating the oil pump gears or the wear surfaces of the housing? If so, the simple act of cleaning these components may have opened up the clearances and small grooves enough to help it to lose its prime. It would be even worse if the gears were reused but turned around from their original orientation. None of the fine grooves they may have created between them over time would line up. The same would be true of new gears in a worn housing. If you can hang a fingernail on either housing surface when moving across it, you have wear that should be addressed.
At this point I would replace the oil pump in its entirety for good measure and henceforth be certain a good seal exists between the pickup tube and the pump if that might have been the problem. Either way, I see you needing to go back in there so the pump assembly might as well be replaced to protect your investment. You may not have destroyed your engine yet, but you might want to peek at a couple of the bearings while you have it out to make the determination if they need replacing at this point.
Best of luck to you with this, it could've been worse.
It sounds like you are drawing air on startup until the pump draws enough suction to fully prime itself. Once primed, it does a far better job maintaining suction due to the oil better filling the clearances between and around the gears. Excessive clearance between the gears and the housing could conceivably cause this as well.
I don't buy the stuck relief valve theory because the "relieved" oil goes to the pan and doesn't just bypass the filter, but bypasses everything. A relief valve stuck partially open would make the most pressure it could make at cold start and steadily decline as the oil thinned, possibly to zero.
If the oil filter's internal bypass was stuck open oil pressure would still be reasonably high when cold, depending on bearing tolerances and other pressure lubricated tolerances, and would taper off as the oil heated and thinned. Having changed the filter to no effect would have eliminated it as a focus even if the symptomology was pointing to it, which it was not.
Was there any carbon, varnish, or golden to reddish-brown residue coating the oil pump gears or the wear surfaces of the housing? If so, the simple act of cleaning these components may have opened up the clearances and small grooves enough to help it to lose its prime. It would be even worse if the gears were reused but turned around from their original orientation. None of the fine grooves they may have created between them over time would line up. The same would be true of new gears in a worn housing. If you can hang a fingernail on either housing surface when moving across it, you have wear that should be addressed.
At this point I would replace the oil pump in its entirety for good measure and henceforth be certain a good seal exists between the pickup tube and the pump if that might have been the problem. Either way, I see you needing to go back in there so the pump assembly might as well be replaced to protect your investment. You may not have destroyed your engine yet, but you might want to peek at a couple of the bearings while you have it out to make the determination if they need replacing at this point.
Best of luck to you with this, it could've been worse.
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07-02-2012, 11:17 AM
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I did not notice any wear or odd coatings on my pump gears when i cleaned everything. And i know for a fact they were put back in correctly. Step 1 is tearing into my old filter to check for debris, i will keep you all updated
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07-02-2012, 12:16 PM
#18
If everything functioned correctly except for the oil filter bypass valve, my suspicions are that it would be more likely for the oil filter to become damaged than it would be to actually lose significant oil pressure. The oil pump is a positive displacement pump which should flow nearly 100% of it's expected volume of oil until the pressure exceeds the pump bypass pressure, the only alternative to this is if the pump is failing to pump oil.
I originally asked about aftermarket gears because my suspicions line up with sixshooter's. The oil pump is having difficulty priming for some reason - the most likely scenario (from experience) is that the pump is losing prime somehow and then unable to re-prime quickly, possibly from overclearanced oil pump gears. Alternatively, it can be from a nicked oil-pickup tube or a problem at the pickup tube gasket. The fact that the lifters don't quiet down until the aftermarket OPG picks up pressure confirms that the OPG is functioning correctly; those should quiet down immediately once there is pressure in the system.
I originally asked about aftermarket gears because my suspicions line up with sixshooter's. The oil pump is having difficulty priming for some reason - the most likely scenario (from experience) is that the pump is losing prime somehow and then unable to re-prime quickly, possibly from overclearanced oil pump gears. Alternatively, it can be from a nicked oil-pickup tube or a problem at the pickup tube gasket. The fact that the lifters don't quiet down until the aftermarket OPG picks up pressure confirms that the OPG is functioning correctly; those should quiet down immediately once there is pressure in the system.
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07-02-2012, 01:46 PM
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Well oil filter looked clean, no silverish tint to the oil and no signs of debris in the filter. I will check for pressure when cranking and if that is bad I will be pulling it. Thing is if I pull it i'm most likely going to build a new stout engine. Would a new oil pump be okay or should i go ahead and get better gears for the new housing? Might aswell do it right if I have to do it anyways
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07-02-2012, 01:51 PM
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Well oil filter looked clean, no silverish tint to the oil and no signs of debris in the filter. I will check for pressure when cranking and if that is bad I will be pulling it. Thing is if I pull it i'm most likely going to build a new stout engine. Would a new oil pump be okay or should i go ahead and get better gears for the new housing? Might aswell do it right if I have to do it anyways
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