The Valvoline site shows this spider of GF-7 vs GF-6, and also notes "Timing chain wear protection" and "Piston cleanliness". I've used the search feature, and forgive me if I have some how missed where someone touched in this, but what exactly changed between the two specs to increase timing chain wear protection and piston cleanliness?
GF-7 Timing Chain Wear
- Thread starter Johnny248
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The timing chain wear test is the same, but the wear limit is now 6% lower, so not a big change.
The piston deposit test is the same but now requires a minimum merit rating of 4.6, up from 4.2 (which puts it on par with Dexos1 Gen3). This is only for 0W-20 and thicker grades though.
GF-7 also has a new LSPI test, which isn't shown in that spider chart.
As for what needs to change in the formulation, that's up to the oil formulator to figure out. More moly could help in the timing chain wear test. Piston deposits would be related to the base oil, viscosity modifier, and maybe antioxidants and detergents. Some oils might need reduced calcium to pass the aged oil LSPI test.
Many oils would have already met these requirements with their API SP oil, and they wouldn't need to be reformulated.
The piston deposit test is the same but now requires a minimum merit rating of 4.6, up from 4.2 (which puts it on par with Dexos1 Gen3). This is only for 0W-20 and thicker grades though.
GF-7 also has a new LSPI test, which isn't shown in that spider chart.
As for what needs to change in the formulation, that's up to the oil formulator to figure out. More moly could help in the timing chain wear test. Piston deposits would be related to the base oil, viscosity modifier, and maybe antioxidants and detergents. Some oils might need reduced calcium to pass the aged oil LSPI test.
Many oils would have already met these requirements with their API SP oil, and they wouldn't need to be reformulated.
Interesting. Thanks for pointing it out.
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