early dyno results
#451
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Now I really think this is what was happening when my low oil level light came on. Because after driving hard (I mean, maxing out the 928 on mountain roads), I could not just stop and sit for a minute and start it back up. I had to sit and wait quite a while before I could get rid of the warning light. Maybe I missed the entire point of Ott's discussion. But I am assuming that I've got a foaming mess in the crankcase. Why else would a perfectly functioning car, with oil level topped up, have a low oil warning light come on after hard driving? And not come on under the same circumstances, when not driving it hard?
But I am probably hijacking the original topic of this thread. So ignore me if that's so.
But I am probably hijacking the original topic of this thread. So ignore me if that's so.
#452
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Bill as a bit of data, there is hill on my way to work with a stop light on it. if i try to "launch" from the stop too aggresively it will trigger the low oil warning. the first time it happened i pulled over, shut down, and checked oil level. it was fine. between the two 'marks'
*mobil 15-50
*mobil 15-50
Last edited by Shark_Week; 02-24-2011 at 11:11 PM. Reason: add note
#454
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Bill as a bit of data, there is hill on my way to work with a stop light on it. if i try to "launch" from the stop too aggresively it will trigger the low oil warning. the first time it happened i pulled over, shut down, and checked oil level. it was fine. between the two 'marks'
*mobil 15-50
*mobil 15-50
Valvoline VR1 20-50
#455
Drifting
#456
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No question about that. It just gets really funny, at times, when he's got two sentences of facts, but needs to fill the rest of the page, to make the publisher happy.
I've always thought a "Cliff Note" version would be a ton better.
I've always thought a "Cliff Note" version would be a ton better.
#458
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Bill as a bit of data, there is hill on my way to work with a stop light on it. if i try to "launch" from the stop too aggresively it will trigger the low oil warning. the first time it happened i pulled over, shut down, and checked oil level. it was fine. between the two 'marks'
*mobil 15-50
*mobil 15-50
Or, is your electrical system “dropping out” and re-registering “low oil”?
#459
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I have triggered the low oil level warning while spinning out at a PCA autocross (yeah, lousy driver.) I have also seen it parked with the engine running on steep driveways. Anything that uncovers the sensor.
it also lights up if your con rod nuts ventilate holes in the oil pan.....
it also lights up if your con rod nuts ventilate holes in the oil pan.....
#460
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Oh, I remember now. That should work ok and simple too. Nice if you could get bigger outlet tubes, but hard to do. I've made convoluted CF ducting to fit around all the curves and things in the way. Takes forever.
#461
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#462
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Louie:
Thanks for joining into our discussion. I've made some notes below, in your post and highlighted them with blue.
Louis:
In the ten years that has passed since you did this video of the valve cover, an entire boatload of 928 engines have failed at the track, with windage trays, pan scrapers, lowered sumps, trick this and that, even with dry sumps. They've failed with stock engines..and they apparently fail with stroker engines (I've not lost a stroker engine from this problem...to date.) I've had rods break, with the bearing perfect. I've had dry sump tanks get sucked dry and had engines "stick"...but I've avoided the 2/6 rod bearing issue. I agree that if the engine rpms are kept very low, one might avoid the 2/6 rod bearing problem....if they have are very careful and routinely check/replace the rod bearings on a regular basis. (We actually have a full size engine drawing that we have marked off grids betting where Kibort's rod will come through, when it finally decides to leave.)
I'm thinking that perhaps what we have found here, might be something "new" that hasn't been seen, to date. I'm thinking that if we could figure this out and somehow "correct" this defect, there might actually be some "extra" engines laying around in 10 more years. At the rate they have been "consumed" in the past 10 years, therre will not be many left, 10 more years out. Try and look at this with an "open" mind, as "new" information...not just the same old unresolved problem.
Thanks for joining into our discussion. I've made some notes below, in your post and highlighted them with blue.
Louis:
In the ten years that has passed since you did this video of the valve cover, an entire boatload of 928 engines have failed at the track, with windage trays, pan scrapers, lowered sumps, trick this and that, even with dry sumps. They've failed with stock engines..and they apparently fail with stroker engines (I've not lost a stroker engine from this problem...to date.) I've had rods break, with the bearing perfect. I've had dry sump tanks get sucked dry and had engines "stick"...but I've avoided the 2/6 rod bearing issue. I agree that if the engine rpms are kept very low, one might avoid the 2/6 rod bearing problem....if they have are very careful and routinely check/replace the rod bearings on a regular basis. (We actually have a full size engine drawing that we have marked off grids betting where Kibort's rod will come through, when it finally decides to leave.)
I'm thinking that perhaps what we have found here, might be something "new" that hasn't been seen, to date. I'm thinking that if we could figure this out and somehow "correct" this defect, there might actually be some "extra" engines laying around in 10 more years. At the rate they have been "consumed" in the past 10 years, therre will not be many left, 10 more years out. Try and look at this with an "open" mind, as "new" information...not just the same old unresolved problem.
Yeah, agreed re: Smokey. However, he has done some great research over the years and when he has a picture of an engine with windows in the oil sump and says it looks like a whirling wad of molasses in there, I tend to believe him.
I've never seen the situation you describe where the normal oil fill opening was full of liquid oil. Not to say it can't happen. Could be if the crank was slinging lots of oil, or the hole wasn't shielded. The people who use a simple oil separator down in the hole usually report very little oil spit out that vent. Maybe different circumstances with the engine not run as hard for as long as you experienced. Engines I've seen with the crankcase vent coming directly out of the crankcase have some sort of shield over the end of the tube so it isn't exposed to slung oil. We have to do something similar.
I really don't see the cam cover window full of oil foam in the video. I see a lot of foam spun out against the window by the cam. Sometimes you can see through it. It moves forward and backward on braking and acceleration. It no doubt represents some quantity of foamed liquid oil and subtracts from the reservoir in the sump. How much is caught up in the crank too? Don't know.
The engine was a 5.0L GT mostly stock except for exhaust mods and some tuning. It had a GTS oil sump baffle. 327 dynojet rwhp. Oil was Redline 20W50. I think Redline is supposed to be non-foamy oil. Some rod bearing damage may well have happened on this test, but the oil foam was about the same at the beginning as at the end. Oil temps were ok. I ran it after the video was made on this same day, but not quite as hard. It was at the next track session a month later, at a different track, I noticed a loss of power and higher than normal oil temps and quit. Oil filter had metal in it.
Of course the cam cover vents can be used to vent crankcase blowby. The factory did it, but that doesn't mean it was the best way to handle the problem. If the blowby gases can't get out the crankcase they will go up the oil drain passages and exit the cam cover vents. Then you have to deal with the oil carried along. Longer (higher) cam cover vent tubes have been used and they work up to a point. Don Hanson did that on his engine with the 4 cam cover vents going into hoses where they joined together on top of the intake manifold. Then a hose from there down to a catch can. He didn't lose much oil. I prefer to do what I can to keep any blowby gases and oil from going up the oil drain passages first. The oil drain passages represent a restriction to free flow of the blowby gases from the crankcase. The pressure in the crankcase will be higher than the pressure in the cam cover with the cam cover vent(s) open. That's what forces the gases and oil up into the cam cover. If you close off the cam cover vents, you won't get oil blown up there, but without adequate crankcase venting the pressure will build up high enough to blow something else. Usually one of the 12mm breather hoses goes, or the dipstick comes out, or an oil seal.
I really don't know how to keep the crank out of the oil at higher RPMs with a wet sump. Like you said everything has been thrown at it and the failures still happen. I'd sure like to see something that does the job. The sump cover, windage screen, oil sump spacer, and breather mods I made for my stroker helps, but it isn't a cure. I've seen the oil pressure dip on that evil turn 2 at Spokane. I don't run it on the track anymore and don't want to take the time to do more fixes that may or may not work. I just drive it. I remember talking with Kim Crumb many years ago about the rod bearing issue. He inspected/replaced the rod bearings every 30 hours of running. I think that was track time since he drove his car all over to different tracks. I wonder if he still has that car.
You can use the holey cam cover and see what you find. It's quite interesting to see what's happening in there.
You have an engine picture gridded with speculation where MK's rod will exit? This could be fun. Is it like a pool? I remember seeing Don Hanson's engine block after the problem. It was very nearly cut in two.
#463
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Late MY extra warning can be just monitoring circuit fault check during engine running and not actual level warning. In any case late digital dash has more intelligence build in than early cars.
#464
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In my particlular case as I have the adaptronic ecu , I have just come across a capacitive sensor which monitor the oil level in the sump and feed it too the ecu .
From this I can write the logic so at a predetermined level the fuel will be cut to the engine should the engine reach this critical level .
I can log this, so this will be another indicator as to what is happening in the sump , as I believe it to be the as been pointed by GB that the sump pickup is periodly uncovered with the obvious results .
From this I can write the logic so at a predetermined level the fuel will be cut to the engine should the engine reach this critical level .
I can log this, so this will be another indicator as to what is happening in the sump , as I believe it to be the as been pointed by GB that the sump pickup is periodly uncovered with the obvious results .
#465
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