Re: Yet another oil thread
1. Early build '01 LS6's had the "ring" problem. Chevy went to a different ring system mid year '01. The fix was a ring replacement.
Therefore late '01 and subsequent years did (should) NOT have a "ring" problem.
2. Nevertheless, after the ring fix some still had excessive oil consumption. Defined as >1 qt / 1,000 mi. The fix is to replace the faulty PVC pick-up under the valley cover and replace the valley cover seal. '04's and later came with the impproved Valley Seal and PVC pick-up.
The above fixes should substantially reduce oil consumption on a street driven car.
Note that the LS6/7 will consume more oil if pressed under hard acceleration or high rev applications as seen in even occasional drag racing, AutoX and Solo I track events and definetly in a dedicated racer.
On any Z06 that sees track or competition the following additional methods should be considered.
3.a. For LS6 wet sump: Additional 1 qt. overfill. Total 7.5 qts. IS A MUST !
3.b. For LS7 dry sump: Consider installing the bigger, later year and ZR1 dry sump reservoir.
4. Install a PVC Catch Can
5. After initial engine break-in (> 1,000 mi.) and preferrably between 2,000 - 5,000 mi. the rings can be "race set" by running Kendall SAE 30 non-synthetic racing oil in 2 sets of 1,500 mi each. Then switching back to synthetic racing oil.
6. You can run a higher weight racing oil such as Mobil 1 10W30, 15W50, or AMSOIL 10W40. This should be used only if there is a decrease in pressure under HOT conditions. Be sure to swiitch to a lighter weight for cooler and cold conditions.
Other options for severe racing applications are:
7. Blueprinted, polished, ported and reshimmed (for higher pressure) OEM engine oil pump OR a Melling racing OEM replacement pump.
8. Installing an engine oil cooler if not equipped.
9. Upgrading the coolant system.
10. Upgrading to an aftermarket dry sump system from ARE or Daily Engineering.
In your case, since you have run the Castrol non-synthetic and done a "race seating" of the rings and have the catch can already installed; I would recommend having the PVC pick-up and Valley Cover seal replaced and run a lighter weight synthetic oil (5W30 or 10W30). Then do an oil consumption test.
A side note here: Some racers, run a higher pressure (60-65 psi), ported, polished and blueprinted pump and run 0W20 racing oil to have better oiling, cooling, oil flow with higher pressures. This nets better HP and faster rev up. You MUST run the racing pump with higher pressures AND a high quality racing oil such as Silkolene Synthetic Pro Racing 0W20 with Friction Modifiers and high film strength.