track 928 oil pressure drop?????UPDATE FILTER OPEN :>(
#136
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Rod bearing inspection-replacement is a VERY good idea for track 928's...a nice bit of insurance vs a ventilated block, that I wasn't very far away from
#137
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Hey I can't remember if I stuck this up in another post already or not, but I always use transmission assembly lube I think many of the engine assembly lubes are too thin. Before I put the t-belt on spin up the oil pump with a right angle drill or the like and have someone say when the motor starts making pressure. Then when it's back together you won't have to wait for it to prime.
Oil pooling in big DOHC heads must be relavent to BMW too, as they used two small electric oil pumps on the M5 to return oil to the pan when cornering hard.
Oil pooling in big DOHC heads must be relavent to BMW too, as they used two small electric oil pumps on the M5 to return oil to the pan when cornering hard.
#138
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No, Spec E30 racers, say, suck in aerated oil and this causes a pressure drop. Lots and lots of data there. I agree that many engines do uncover the pickup under various conditions but it is hardly universal.
#140
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look at the oil level pictures I simulated with water. you are not going to uncover the pickup with 1g of cornering force, nor braking force. the aeation, due to foaming oil would be a answer, or too much oil stuffed in the head, but Im thinking that problem might only exist for the open road racers that go 6000rpm for 30 mins straight.
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#141
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Mark--
Take a few quarts out of the sump, simulating the oil moved to the heads under higher loads. Now aerate the oil in the sump, with only the bottom 30% actually liquid; simulate that by taking 3 more quarts out of the sump. Now tilt the sump to a 45º angle to simulate 1G loading in cornering and/or braking. Is the pickup still covered?
Take a few quarts out of the sump, simulating the oil moved to the heads under higher loads. Now aerate the oil in the sump, with only the bottom 30% actually liquid; simulate that by taking 3 more quarts out of the sump. Now tilt the sump to a 45º angle to simulate 1G loading in cornering and/or braking. Is the pickup still covered?
#142
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why is the oil being aearated? 3 quarts missing and the oil level is way below the crank! way below . proof is that I still have 4-5 bar pressure at 1.4 gs over a 7 second duration, and 5000rpm.
I think if there is problems due to foaming its the oil, not the system, or I would have grenaded my engine 10 years ago and so would have scot.
I think if there is problems due to foaming its the oil, not the system, or I would have grenaded my engine 10 years ago and so would have scot.
Mark--
Take a few quarts out of the sump, simulating the oil moved to the heads under higher loads. Now aerate the oil in the sump, with only the bottom 30% actually liquid; simulate that by taking 3 more quarts out of the sump. Now tilt the sump to a 45º angle to simulate 1G loading in cornering and/or braking. Is the pickup still covered?
Take a few quarts out of the sump, simulating the oil moved to the heads under higher loads. Now aerate the oil in the sump, with only the bottom 30% actually liquid; simulate that by taking 3 more quarts out of the sump. Now tilt the sump to a 45º angle to simulate 1G loading in cornering and/or braking. Is the pickup still covered?
#143
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Mark--
Take a few quarts out of the sump, simulating the oil moved to the heads under higher loads. Now aerate the oil in the sump, with only the bottom 30% actually liquid; simulate that by taking 3 more quarts out of the sump. Now tilt the sump to a 45º angle to simulate 1G loading in cornering and/or braking. Is the pickup still covered?
Take a few quarts out of the sump, simulating the oil moved to the heads under higher loads. Now aerate the oil in the sump, with only the bottom 30% actually liquid; simulate that by taking 3 more quarts out of the sump. Now tilt the sump to a 45º angle to simulate 1G loading in cornering and/or braking. Is the pickup still covered?
The oil pump in the 928 is oversize and now we know from careful examination of development pictures that it is over-driven. The pump also communicates internally and the relief circuit recycles output internally. These factors, among others, allow it to operate with an input of highly aerated oil, so removing three quarts of air/oil from the sump is dubious. Observation of Louie's video also makes a resultant claim of approximately four quarts of air/oil mix in the heads suspect -- this is about 4000cc by volume.
#144
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why is the oil being aearated? 3 quarts missing and the oil level is way below the crank! way below . proof is that I still have 4-5 bar pressure at 1.4 gs over a 7 second duration, and 5000rpm.
I think if there is problems due to foaming its the oil, not the system, or I would have grenaded my engine 10 years ago and so would have scot.
I think if there is problems due to foaming its the oil, not the system, or I would have grenaded my engine 10 years ago and so would have scot.
#145
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I kind of get it.
by the way, when i take a oil level reading after a hard race, i dont see any bubbles on the dip stick. i wonder if that amsoil is just that good in fighting off the foam!![Smilie](https://rennlist.com/forums/images/smilies/smile.gif)
by the way, when i take a oil level reading after a hard race, i dont see any bubbles on the dip stick. i wonder if that amsoil is just that good in fighting off the foam!
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#147
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Rockrete this isn't a good option for a V8. Too much oil will cause immediate aeration, and also ingestion. It's a pretty complicated equation to solve. I recommend you always run an accusump in more than road conditions. Brian, sorry to hear this, but hey I have a spare S4 motor here if you need it ![Smilie](https://rennlist.com/forums/images/smilies/smile.gif)
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#148
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Translated: use an oil cooler.
Last edited by Kevin Johnson; 05-15-2011 at 10:39 AM. Reason: spelling
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#150
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Multiple taps on the sump for sight glasses are also places where things can leak or get broken off.
To see oil foaming in the sump by way of a side-tapped sight glass is tough. Virtually impossble in a classic bottom tap, vented-top sight glass. You really want bulls-eye window glasses at various locations on the sump sides. They would let you view the actual conditions inside the sump.
To see oil foaming in the sump by way of a side-tapped sight glass is tough. Virtually impossble in a classic bottom tap, vented-top sight glass. You really want bulls-eye window glasses at various locations on the sump sides. They would let you view the actual conditions inside the sump.