2/6 rod bearing flow tests
03-01-2012, 03:01 PM
#31
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My apologies: poor choice of words: head is visualizing one thing, fingers are typing another.
I came up with a great concept over lunch: need to make a mock-up & take by my two racing machinests, get their opinions. I agree that there's no way to remove all air, but if you could keep the sump from pulling air during high-g turns, as the OB pans gain about 5 seconds more "before starvation" life to your engine, this could significantly help. The biggest problem I see with the OB pan is that oil can still slosh out past the screen on high-G turns. Higher RPM's appear to require drilling of the crank, something that I think most DE'ers are not up to doing yet on their otherwise healthy, semi-stock engines.
I came up with a great concept over lunch: need to make a mock-up & take by my two racing machinests, get their opinions. I agree that there's no way to remove all air, but if you could keep the sump from pulling air during high-g turns, as the OB pans gain about 5 seconds more "before starvation" life to your engine, this could significantly help. The biggest problem I see with the OB pan is that oil can still slosh out past the screen on high-G turns. Higher RPM's appear to require drilling of the crank, something that I think most DE'ers are not up to doing yet on their otherwise healthy, semi-stock engines.
03-01-2012, 03:03 PM
#32
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Mark.
12-09-2012, 03:48 AM
#34
Makes sense, twice the cylinders and twice the oiling issues as the 944 engine.I'll be relocating the sway bar on my swap to keep a large rear-sump pan. I'm surprised I haven't seen a rear-sumped 928 from one of the racers.
12-09-2012, 11:43 AM
#35
Drifting
this has such few views because the 2\6 issues were found to be due to oil packing in the heads causing the aeration issue at pickup and starvation starting at the 2\6.
I know greg has offered a fix and I think carl is working on his own since the discovery during an engine dyno session...
I know greg has offered a fix and I think carl is working on his own since the discovery during an engine dyno session...
12-09-2012, 12:47 PM
#36
Drifting
Is there an oil capacity difference between 2 valve 4.7 euro and the 4 valve 5.4 gts?
12-09-2012, 01:05 PM
#37
Nordschleife Master
this has such few views because the 2\6 issues were found to be due to oil packing in the heads causing the aeration issue at pickup and starvation starting at the 2\6. I know greg has offered a fix and I think carl is working on his own since the discovery during an engine dyno session...
Even the best dry sump system with active air-oil separators is going to have air bubbles in oil. This is probably even more true with the existing 928 dry sump systems which use the stock pump as the pressure pump. And yet even more true when talking about wet sump engines, even with scavenge assist.
Fixing the girdle to distribute oil and air evenly to all mains is something that I think one should do even if one has figured out a way to keep the oil pickup from uncovering. If the air is distributed evenly, the threshold amount of air bubbles in oil causing the engine to grenade increases.
12-10-2012, 12:17 AM
#39
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Other oil control and crankcase breather systems aside, Greg's girdles aren't exactly stock either, with respect to the 2/6 region.
12-10-2012, 05:28 PM
#41
What type pump is that?
From the experiment pics, it looks just like a problem a local oilfield co. had with a large pump engine. We simply took the block and machined the channel 25% wider and never seen a fried bearing since.
From the experiment pics, it looks just like a problem a local oilfield co. had with a large pump engine. We simply took the block and machined the channel 25% wider and never seen a fried bearing since.
12-10-2012, 05:36 PM
#42
Nordschleife Master
It's an idler pulley. It does nothing except keeps the timing belt happy. It's obviously a part of a true dry sump system with an external pressure pump.
The Europeans are light years ahead of us in terms of this oiling stuff, and we haven't even woken up to the fact! ;-)
Uwe "VdW.MS", please email or pm me if you happen to check the RL. I would very much like to hear more about your project. Spreche kein Deutsch, but google translates...
The Europeans are light years ahead of us in terms of this oiling stuff, and we haven't even woken up to the fact! ;-)
Uwe "VdW.MS", please email or pm me if you happen to check the RL. I would very much like to hear more about your project. Spreche kein Deutsch, but google translates...
Last edited by ptuomov; 12-10-2012 at 05:59 PM.
