Anyone ever hear of Bearing washing out cause of to much oil psi?
05-05-2009, 06:57 PM
#3
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He might have been talking about the problem the old big blocks had. At high rpm, too much oil pressure and it would pump all the oil to the top of the motor, not drain back down fast enough, and starve the bottom end. I have never heard of this being a problem with LS motors.
05-06-2009, 06:20 AM
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Can you elaborate on that a little? What oiling problems do LS1's have, and what changes did they make on the LS6 to address it? This is the first I have heard of this. I thought the LS6 was basically the same other than a minor change to the block for strength (yes I know the heads and cam are different).
05-06-2009, 08:26 AM
#6
The LS6 block has windows cast into the crankcase area to allow better ventilation of gaseous pressures, located between each crank journal space. It's possible this design was carried into the LS2 and up blocks but I haven't looked into it. Very little to do with "oiling" per se, just mananging crankcase pressure better.
Apart from that, I've not seen any other oiling improvements designed into the LS6. The routing of pressurized oil is identical in every GM drawing I've seen. The only documented design change involving oil I saw was the compression ring packs, which resolved oil consumption problems from ring flutter.
As far as oiling having been a problem on the LS1, I'd like to see documentation of that claim. Here are two examples proving the opposite:
The old ASA racing series used LS1 crate engines with GM's ASA camshaft, the only problem they documented early on was the connecting rod bolts and this was addressed in the 2001 production change to upgraded bolts.
Another good example was the C5 Vettes at Bondurant Racing School, just plain old LS1 engines getting the snot beaten out of them with no oiling system modifications. They blew two engines right off the bat, same failure mode (#4 rod bearing if I recall right) so they consulted with GM and the result was a switch to thicker oil. Mobil-1 15W-50 synth. No oil cooler, no aux pressurization system, just thicker oil. No further engine failures from oiling problems, and the car I abused...uh, drove...was showing 300-310degF oil temps on the DIC most of the track time.
Google ASA + LS1 and you'll find more info, this one is a good start:
http://www.engineering.com/Library/A...wn-effect.aspx
Apart from that, I've not seen any other oiling improvements designed into the LS6. The routing of pressurized oil is identical in every GM drawing I've seen. The only documented design change involving oil I saw was the compression ring packs, which resolved oil consumption problems from ring flutter.
As far as oiling having been a problem on the LS1, I'd like to see documentation of that claim. Here are two examples proving the opposite:
The old ASA racing series used LS1 crate engines with GM's ASA camshaft, the only problem they documented early on was the connecting rod bolts and this was addressed in the 2001 production change to upgraded bolts.
Another good example was the C5 Vettes at Bondurant Racing School, just plain old LS1 engines getting the snot beaten out of them with no oiling system modifications. They blew two engines right off the bat, same failure mode (#4 rod bearing if I recall right) so they consulted with GM and the result was a switch to thicker oil. Mobil-1 15W-50 synth. No oil cooler, no aux pressurization system, just thicker oil. No further engine failures from oiling problems, and the car I abused...uh, drove...was showing 300-310degF oil temps on the DIC most of the track time.
Google ASA + LS1 and you'll find more info, this one is a good start:
http://www.engineering.com/Library/A...wn-effect.aspx
05-06-2009, 02:41 PM
#7
In road racing apps there have been instances of spun bearings due to the pump nearly emptying the pan at sustained high rpm and the g force sloshing the oil away from the pick up tube.
It is why there are some aftermarket pans available with different baffles designed to help keep more oil around the pickup area.
It why most RR and AX guys run 6.5-7 qts of oil in a 5.5qt f-body pan.
It is why some do the lifter tray mod to speed up the return of oil to the pan.
It is not usually a problem in a street/strip car but in extreme apps it can POSSIBLY be a problem.
Oh... and a vette has a different pan too so maybe that helps over the f-body pan...
It is why there are some aftermarket pans available with different baffles designed to help keep more oil around the pickup area.
It why most RR and AX guys run 6.5-7 qts of oil in a 5.5qt f-body pan.
It is why some do the lifter tray mod to speed up the return of oil to the pan.
It is not usually a problem in a street/strip car but in extreme apps it can POSSIBLY be a problem.
Oh... and a vette has a different pan too so maybe that helps over the f-body pan...
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05-06-2009, 03:53 PM
#8
In road racing apps there have been instances of spun bearings due to the pump nearly emptying the pan at sustained high rpm and the g force sloshing the oil away from the pick up tube.
It is why there are some aftermarket pans available with different baffles designed to help keep more oil around the pickup area.
It why most RR and AX guys run 6.5-7 qts of oil in a 5.5qt f-body pan.
It is why some do the lifter tray mod to speed up the return of oil to the pan.
It is not usually a problem in a street/strip car but in extreme apps it can POSSIBLY be a problem.
Oh... and a vette has a different pan too so maybe that helps over the f-body pan...
It is why there are some aftermarket pans available with different baffles designed to help keep more oil around the pickup area.
It why most RR and AX guys run 6.5-7 qts of oil in a 5.5qt f-body pan.
It is why some do the lifter tray mod to speed up the return of oil to the pan.
It is not usually a problem in a street/strip car but in extreme apps it can POSSIBLY be a problem.
Oh... and a vette has a different pan too so maybe that helps over the f-body pan...
All true statements, but none of which is indicative of an oiling problem inherent to the LS1 engine which, you claim, caused the LS6 to supersede it.
05-07-2009, 10:48 AM
#10
FormerVendor
The ASA engines are a modified drysump design to keep the engines alive. They do not use the OEM oil sytem but do use stock pump for a pressure only pump. LSx design has problems foaming oil from excessive windage and poor oil drainback.
The LS6 block has windows cast into the crankcase area to allow better ventilation of gaseous pressures, located between each crank journal space. It's possible this design was carried into the LS2 and up blocks but I haven't looked into it. Very little to do with "oiling" per se, just mananging crankcase pressure better.
Apart from that, I've not seen any other oiling improvements designed into the LS6. The routing of pressurized oil is identical in every GM drawing I've seen. The only documented design change involving oil I saw was the compression ring packs, which resolved oil consumption problems from ring flutter.
As far as oiling having been a problem on the LS1, I'd like to see documentation of that claim. Here are two examples proving the opposite:
The old ASA racing series used LS1 crate engines with GM's ASA camshaft, the only problem they documented early on was the connecting rod bolts and this was addressed in the 2001 production change to upgraded bolts.
Another good example was the C5 Vettes at Bondurant Racing School, just plain old LS1 engines getting the snot beaten out of them with no oiling system modifications. They blew two engines right off the bat, same failure mode (#4 rod bearing if I recall right) so they consulted with GM and the result was a switch to thicker oil. Mobil-1 15W-50 synth. No oil cooler, no aux pressurization system, just thicker oil. No further engine failures from oiling problems, and the car I abused...uh, drove...was showing 300-310degF oil temps on the DIC most of the track time.
Google ASA + LS1 and you'll find more info, this one is a good start:
http://www.engineering.com/Library/A...wn-effect.aspx
Apart from that, I've not seen any other oiling improvements designed into the LS6. The routing of pressurized oil is identical in every GM drawing I've seen. The only documented design change involving oil I saw was the compression ring packs, which resolved oil consumption problems from ring flutter.
As far as oiling having been a problem on the LS1, I'd like to see documentation of that claim. Here are two examples proving the opposite:
The old ASA racing series used LS1 crate engines with GM's ASA camshaft, the only problem they documented early on was the connecting rod bolts and this was addressed in the 2001 production change to upgraded bolts.
Another good example was the C5 Vettes at Bondurant Racing School, just plain old LS1 engines getting the snot beaten out of them with no oiling system modifications. They blew two engines right off the bat, same failure mode (#4 rod bearing if I recall right) so they consulted with GM and the result was a switch to thicker oil. Mobil-1 15W-50 synth. No oil cooler, no aux pressurization system, just thicker oil. No further engine failures from oiling problems, and the car I abused...uh, drove...was showing 300-310degF oil temps on the DIC most of the track time.
Google ASA + LS1 and you'll find more info, this one is a good start:
http://www.engineering.com/Library/A...wn-effect.aspx
05-07-2009, 10:49 AM
#11
FormerVendor
05-07-2009, 11:07 AM
#12
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Nice thanks guy for all the great answers. Is there any ways to help the LS engines with oil drain back other then going with link bar lifters to get rid of the lifter trays ?
05-07-2009, 03:04 PM
#15
i never saw it till after my motor was together or else i might have done it.
how much oil actually gets stuck there though?
if it was a big issue, you think GM would have pull little holes in it from the factory
how much oil actually gets stuck there though?
if it was a big issue, you think GM would have pull little holes in it from the factory
05-07-2009, 04:50 PM
#17
yes, but i still dont understand how THAT (the trays) would be a major factor in the drain back process. at 7500 rpms, wouldnt it be more about flowing too much oil and not that some is stuck in a lifter tray?
im not trying to argue, i just dont understand how the lifter tray could be a big restriction. does that much oil actually get trapped there?
im not trying to argue, i just dont understand how the lifter tray could be a big restriction. does that much oil actually get trapped there?
05-07-2009, 05:27 PM
#19
Yup, and the up/down motion of the lifters should have the effect of ejecting some (if not most) of the oil trapped in the trays.
05-07-2009, 06:21 PM
#20
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yes, but i still dont understand how THAT (the trays) would be a major factor in the drain back process. at 7500 rpms, wouldnt it be more about flowing too much oil and not that some is stuck in a lifter tray?
im not trying to argue, i just dont understand how the lifter tray could be a big restriction. does that much oil actually get trapped there?
im not trying to argue, i just dont understand how the lifter tray could be a big restriction. does that much oil actually get trapped there?
As rpms goes up so does the load and forces on the bearings so you need more oil to get to them for lube/cooling. yea why there was a old rule of 10 psi for every 1k rpms. The LS oil pump pumps enough oil to start to empty the pan which might cause it to suck air if its not draining back fast enough.
The lifter trays not a big restriction but every little bit helps