Interesting Quote on the "Ring issue"...
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Racer
Joined: Mar 2002
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From: Mtns of Western NC & SW FLA
Interesting Quote on the "Ring issue"...
Thumbing through the May '05 issue of Corvette Mag.,
pg 101,:
"Many owners of 1999-2002 LS1s and LS6s experience excessive oil consumption. It's worse in some cars and doesn't occur at all in others, so the logical assumption is that there is something wrong with some engines, (even though owners are told the consumption is 'normal' by dealers.) Well, something is indeed wrong, but it turns out the problem is endemic to all '99-'02 LS1s and LS6s."
Etc, etc...the art. goes on to "describe" how to and show pics of an engine pull and ring job.
It does say that the effect/prob. is more likely to occur at rpms above 3200 and that manual trans cars see it more frequently, due to higher engine speeds. The #2 compression ring is at fault, states the art.
Not handwringing or paranoid, but
Jes'curious of the Gang's opins/comments on this.
BR, David
pg 101,:
"Many owners of 1999-2002 LS1s and LS6s experience excessive oil consumption. It's worse in some cars and doesn't occur at all in others, so the logical assumption is that there is something wrong with some engines, (even though owners are told the consumption is 'normal' by dealers.) Well, something is indeed wrong, but it turns out the problem is endemic to all '99-'02 LS1s and LS6s."
Etc, etc...the art. goes on to "describe" how to and show pics of an engine pull and ring job.
It does say that the effect/prob. is more likely to occur at rpms above 3200 and that manual trans cars see it more frequently, due to higher engine speeds. The #2 compression ring is at fault, states the art.
Not handwringing or paranoid, but
Jes'curious of the Gang's opins/comments on this.
BR, David
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1999-2002: Service Bulletin: Higher Than Expected Oil Consumption
Subject: Higher Than Expected Oil Consumption (Replace Rings and Engine Valley Cover)
Source: Chevrolet Dealer Technical Service Bulletin
Number: 01-06-01-023A
Models: 1999-2001 Chevrolet Camaro, 1999-2002 Chevrolet Corvette, 1999-2001 Pontiac Firebird, with 5.7L Engine (VINs G, S -- RPOs LS1, LS6)
This bulletin is being revised to add model years for the Corvette, information on the LS6 engine and parts information. Please discard Corporate Bulletin Number 01-06-01-023 (Section 6 - Engine).
Condition
Some owners may comment on higher than expected oil consumption. When checked, the oil consumption could be in the range of 400-600 miles per quart (700-1000 km/L).
On the LS6 engine only, the technician may find oil behind the engine throttle plate and in the intake manifold.
Cause
The cause for this condition may be an interaction between the piston rings and the cylinder bore in vehicles that are operated at higher RPMs -- typically manual transmission vehicles driven in a manner where the engine is frequently or consistently operating at greater than 3200 RPM.
On the LS6 engine only, the engine has a unique aluminum valley cover that has composite oil separating baffles and PCV plumbing incorporated. In some cases, the PCV baffle may not be properly sealed to the valley cover, causing oil to enter the PCV system.
Correction
On the LS6 engine only, replace the engine valley cover if oil is found behind the throttle body or in the intake manifold before replacing the piston ring. Refer to Engine Valley Cover Replacement in the Engine Mechanical - 5.7L subsection of the Corvette Service Manual.
A new set of piston rings is currently available through GMSPO. The new rings are part of a complete piston ring kit. Install only the number 2 compression ring and the oil expander ring from the piston ring kit. All other rings in the piston ring kit should be discarded. The original number 1 compression ring and the oil ring rails should be re-used in their original positions on the piston. All pistons should be used in the same cylinder bore.
Important
Do not dress or hone the cylinder bore. Nothing should be done to change the bore finish for this condition. Changing the bore finish may aggravate the condition.
Refer to the Unit Repair Manual for appropriate ring removal and replacement procedure.
The number 1 compression ring and the upper and lower oil expander rails are re-used because they are already broken in for the bore that they are in. The new number 2 compression ring is made with a very sharp edge that will break in quickly.
Changing only the piston rings noted, with no change in driving style, should change oil consumption to an acceptable level. Changes in driving style that reduce the amount of time spent at higher RPMs will also positively affect oil consumption.
In addition to the standard size piston ring kit listed below, a 0.25 mm oversized piston ring kit is available. The oversized piston ring kit should only be used in those rare instances where the cylinder bore size has been machined larger to accommodate the 0.25 mm oversized piston rings.
.
Subject: Higher Than Expected Oil Consumption (Replace Rings and Engine Valley Cover)
Source: Chevrolet Dealer Technical Service Bulletin
Number: 01-06-01-023A
Models: 1999-2001 Chevrolet Camaro, 1999-2002 Chevrolet Corvette, 1999-2001 Pontiac Firebird, with 5.7L Engine (VINs G, S -- RPOs LS1, LS6)
This bulletin is being revised to add model years for the Corvette, information on the LS6 engine and parts information. Please discard Corporate Bulletin Number 01-06-01-023 (Section 6 - Engine).
Condition
Some owners may comment on higher than expected oil consumption. When checked, the oil consumption could be in the range of 400-600 miles per quart (700-1000 km/L).
On the LS6 engine only, the technician may find oil behind the engine throttle plate and in the intake manifold.
Cause
The cause for this condition may be an interaction between the piston rings and the cylinder bore in vehicles that are operated at higher RPMs -- typically manual transmission vehicles driven in a manner where the engine is frequently or consistently operating at greater than 3200 RPM.
On the LS6 engine only, the engine has a unique aluminum valley cover that has composite oil separating baffles and PCV plumbing incorporated. In some cases, the PCV baffle may not be properly sealed to the valley cover, causing oil to enter the PCV system.
Correction
On the LS6 engine only, replace the engine valley cover if oil is found behind the throttle body or in the intake manifold before replacing the piston ring. Refer to Engine Valley Cover Replacement in the Engine Mechanical - 5.7L subsection of the Corvette Service Manual.
A new set of piston rings is currently available through GMSPO. The new rings are part of a complete piston ring kit. Install only the number 2 compression ring and the oil expander ring from the piston ring kit. All other rings in the piston ring kit should be discarded. The original number 1 compression ring and the oil ring rails should be re-used in their original positions on the piston. All pistons should be used in the same cylinder bore.
Important
Do not dress or hone the cylinder bore. Nothing should be done to change the bore finish for this condition. Changing the bore finish may aggravate the condition.
Refer to the Unit Repair Manual for appropriate ring removal and replacement procedure.
The number 1 compression ring and the upper and lower oil expander rails are re-used because they are already broken in for the bore that they are in. The new number 2 compression ring is made with a very sharp edge that will break in quickly.
Changing only the piston rings noted, with no change in driving style, should change oil consumption to an acceptable level. Changes in driving style that reduce the amount of time spent at higher RPMs will also positively affect oil consumption.
In addition to the standard size piston ring kit listed below, a 0.25 mm oversized piston ring kit is available. The oversized piston ring kit should only be used in those rare instances where the cylinder bore size has been machined larger to accommodate the 0.25 mm oversized piston rings.
.
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I agree, Grumpy. I guess the magazine is just trying to get the info out to more and more people. The dealer doesn't tell you this stuff rountinely - they kind of leave it up to you to bring these issues to their attention when technical service bulletins are issued.
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I have to wonder how many people with "garage queens" will get bit by this in the distant future. GMs fault, no warranty, &%#tty position to find yourself in.
Thread Starter
Racer
Joined: Mar 2002
Posts: 399
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From: Mtns of Western NC & SW FLA
G: the long art. I quoted from did ref that bulletin and spent 3 pages of pics and "instructions" on how to re-ring it. Agree the mag, like all the Vette mags I've read, are too general, have DIY stuff that is simplistic or too tech for a backyard guy, etc. But, wonder what your opin is on the potential for this ring wear/oil consump. issue to crop up?
Fwiw, our '02 Vert, with 18K, (some of that v.vigorous via the MN6), has consumed v.little oil between changes.
BR,David
Fwiw, our '02 Vert, with 18K, (some of that v.vigorous via the MN6), has consumed v.little oil between changes.
BR,David
Le Mans Master
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From: Tampa FL
Originally Posted by motordavid
G: the long art. I quoted from did ref that bulletin and spent 3 pages of pics and "instructions" on how to re-ring it. Agree the mag, like all the Vette mags I've read, are too general, have DIY stuff that is simplistic or too tech for a backyard guy, etc. But, wonder what your opin is on the potential for this ring wear/oil consump. issue to crop up?
Fwiw, our '02 Vert, with 18K, (some of that v.vigorous via the MN6), has consumed v.little oil between changes.
BR,David
Fwiw, our '02 Vert, with 18K, (some of that v.vigorous via the MN6), has consumed v.little oil between changes.
BR,David
