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Discussion Starter #1 (Edited)
Here is some interesting info about the LS1 ans LS6 that GM will not tell you.

The LS1 and LS6 both have excessive oil blow through right offf the factory show room floor.

It starts at the PCV tube located on the right side of yor engine and goes straight to a vacuum port on the right side of your intake manifold directly behind the throttle body. What happens is this oil vapor coming in to the front of the intake manifold eventually starts to build up and there for creates a disturbance in air flow as well as gumming up the tops of your valves and eventually starts to decreases your engines performance over time.

The good news is that in one hour you can prevent this oil vapor from coming back in to your intake.

take a look at these photos of a filtration and oil scavenge I installed. If you look at the bottom of the glass you can see the oil it's filtered out the past 90 days.





I have put together a kit to fix this problem for $49.00 including shipping. If you are interested in purchasing one please send me a e-mail.

I seem to be having a problem posting photos if you would like to see them take a look at my gallery or I can e-mail them to you. sorry about that. :(
 

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Interesting, I've heard about the piston rings needing replacement but, this is a new one to me. Thanks for the info.
 

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Iv'e seen people make those catch cans in the PCV system.I never lost a drop between oil changes.I homeported and polished my throttle body(like a mirror).When i had it off the car,i noticed that the PCV tunnel thru the body was almost big enough to stick my thumb thru.I filled the tunnel with JBweld,then drilled a 1/4 inch hole thru it.I have a real snappy throttle response now,i don't know if it's from filling the hole,or porting the t-body or both.Never lose oil,i race pretty regularly too.
Check out this site. www.ls1howto.com thats were i got my "game plan" from.
 

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Discussion Starter #4
LS-1 LS-6 Oil Bloy By.

Hawaii,

Thats a pretty slick web site I've never seen it before.
I have also seen people do the same as you did with the JB weld and then drilling it's a pretty good idea.

I should have been more clear in something though before you did your engine mods you say you never lost oil? Good you shouldent what is going back in to the intake is oil vapor which after time turns in to a black mess of crap in your intake.

Myself and a friend took his LS-1 intake off a 99 C-5 and replaced it with a nice polished aluminum intake. We debated putting the old intake for sale on ebay but instead we opted to sacrafice it to the intake gods and we put it in the chop saw and cut it in half and then in to quarters.

What a fricking mess the inside of that intake was from all the oil vapor build up! Oh by the way his car had 22,000 miles on it. Well guess what the next thing we did was? you got it a filter on that sucker.

Anyhow if you happen to know of anyone with one of the limited edition Ford Harley Davidson trucks with the factory kenny bell super charger tell them to do the same they are 10 times worse about blow by them the LS-1 or LS-6.
 

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I just saw one of those trucks today
I i didn't notice that much oil behind the throttle plate or in the mainifold.There was a like other cars PCV systems leave,but if it's excessive like the one you saw,that could lead to carbon build up and a pinging problem (like i had)plus to much coming thru there could evaporate or burn off at the combustion chamber and make an owner think there losing oil thru the rings,but thats not exactly proven yet......this is the GM service bulletin...I think it's member VPRSNK that is having her car re-ringed right now due to oil consumption.

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 06 - Engine/Propulsion System).

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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HI there,

As for the PCV issue and the throttle body. Your fresh air intake is directly in front of the throttle body blade for the PCV system. The PCV inlet from the valve is directly behind the blade. Under excessive high rpm usage, this creates vapor that is pumped into the engine through the PCV, due to oil windage inside the crankcase. Under more extreme racing conditions, the oil vapor cannot be all sucked up through the PCV valve to the engine. The extra vapor is sometimes channeled back through the fresh air tube, and into the throttle body duct, in front of the blade. It then condenses inside the duct, where it is colder.

I recently conducted a seminar at a local dyno shop. We used a '96 LT4, '89 L98, and a '04 LS6. In each case, during the dyno run, a vacuum gauge was installed in the PCV hose, in between the engine and the intake manifold.

Normally, full manifold vacuum is acheived. However, under the dyno run, with all in 4th gear, a pressure of between 1-3 psi was created above 4000-4500 rpm. When pressure is acheived, where does it go???????? To the least place of restriction, the fresh air intake. This is because the PCV valve is NOT wide open, as you know. This is a fixed vacuum leak to burn oil vapor produced inside an engine. This is how I illustrated how windage, high rpm, oil residue in the throttle body, and increased oil consumption at higher rpm all interrelate.

I hope that this answers all your questions, and if you have anything further, please ask away. However, why would Corvette engineering install a revised PCV ystem on the LS6, and then retrofit to LS1?

Now, this similar system is used on LS2. If there was that much of an issue, then every single Gen 3 powered car will use at least 1 quart every 1000 miles. And, of course, that just does not happen.

Allthebest,
c4c5:bang
 

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Nice info, great idea for a vacuum test in the PCV hose.
 

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anyone heard of this yet???

Higher Than Expected Oil Consumption (Replace Rings and Engine Valley Cover) #01-06-01-023A - (Jun 19, 2002)
Higher Than Expected Oil Consumption (Replace Rings and Engine Valley Cover)
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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Look 3 posts above yours....:D
 

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HI there,

As for the PCV issue and the throttle body. Your fresh air intake is directly in front of the throttle body blade for the PCV system. The PCV inlet from the valve is directly behind the blade. Under excessive high rpm usage, this creates vapor that is pumped into the engine through the PCV, due to oil windage inside the crankcase. Under more extreme racing conditions, the oil vapor cannot be all sucked up through the PCV valve to the engine. The extra vapor is sometimes channeled back through the fresh air tube, and into the throttle body duct, in front of the blade. It then condenses inside the duct, where it is colder.

I recently conducted a seminar at a local dyno shop. We used a '96 LT4, '89 L98, and a '04 LS6. In each case, during the dyno run, a vacuum gauge was installed in the PCV hose, in between the engine and the intake manifold.

Normally, full manifold vacuum is acheived. However, under the dyno run, with all in 4th gear, a pressure of between 1-3 psi was created above 4000-4500 rpm. When pressure is acheived, where does it go???????? To the least place of restriction, the fresh air intake. This is because the PCV valve is NOT wide open, as you know. This is a fixed vacuum leak to burn oil vapor produced inside an engine. This is how I illustrated how windage, high rpm, oil residue in the throttle body, and increased oil consumption at higher rpm all interrelate.

I hope that this answers all your questions, and if you have anything further, please ask away. However, why would Corvette engineering install a revised PCV ystem on the LS6, and then retrofit to LS1?

Now, this similar system is used on LS2. If there was that much of an issue, then every single Gen 3 powered car will use at least 1 quart every 1000 miles. And, of course, that just does not happen.

Allthebest,
c4c5:bang
Would a catch can help on both the PCV and the fresh air intake tube to the throttle body on the LT1/4?
 
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