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C6 Corvette ZR1 & Z06General info about GM’s Corvette Supercar, LS9 Corvette Technical Info, Performance Upgrades, Suspension Setup for Street or Track
Just saw an interesting story. General motors is now selling a new version of the LS7 as a crate motor. Specs are 570 hp and 540 lb-ft of torque. Dubbed the LS7/570. Its apparently modified with high rate valve springs, high lift cam, Z28 exhaust manifolds ,and here's the kicker.....new cylinder heads. Maybe fixed ones??
Not 'fixed', redesigned.
Catastrophic valve failure is due to it's poor design from '06 to '13 + Z28.
So now in the year of our Lord 2020, GM got around to redesigning 'em, huh.
Hey maybe these new heads will fit C6.
The problem with production LS7 heads is not a design issue.
It was a manufacturing quality control problem. Had Linamar, the company which did all machining on production LS7 heads, machined the heads to print, there never would have been a problem.
Just saw an interesting story. General motors is now selling a new version of the LS7 as a crate motor. Specs are 570 hp and 540 lb-ft of torque. Dubbed the LS7/570. Its apparently modified with high rate valve springs, high lift cam, Z28 exhaust manifolds ,and here's the kicker....new cylinder heads. Maybe fixed ones??
Not 'fixed', redesigned.
Catastrophic valve failure is due to it's poor design from '06 to '13 + Z28.
So now in the year of our Lord 2020, GM got around to redesigning 'em, huh.
Not 'fixed', redesigned.
Catastrophic valve failure is due to it's poor design from '06 to '13 + Z28.
So now in the year of our Lord 2020, GM got around to redesigning 'em, huh.
Hey maybe these new heads will fit C6.
The problem with production LS7 heads is not a design issue.
It was a manufacturing quality control problem. Had Linamar, the company which did all machining on production LS7 heads, machined the heads to print, there never would have been a problem.
The problem with production LS7 heads is not a design issue. It was a manufacturing quality control problem. Had Linamar, the company which did all machining on production LS7 heads, machined the heads to print, there never would have been a problem.
It was more than that Hib. GM cheaped out on the TI intake valve stem finish too. There's been a ton of cases where geometry had been corrected and there's still been rapid guide wear due to the relatively abrasive valve stem finish. Tumbling the intake valves was a band-aide repair that never really fixed the real problem. That's the main reason that your buddy (lol) Katech replaces all OEM intake valves with their moly coated TI valves.
The problem with production LS7 heads is not a design issue.
It was a manufacturing quality control problem. Had Linamar, the company which did all machining on production LS7 heads, machined the heads to print, there never would have been a problem.
In the beginning valvetrain failures were attributed to a QC issue in manufacturing, and it may have been.
So what MY was this QC issue rectified?
Moreover, why is it all LS7 from '05-'13 have reported same issue?
I respect your 2 cents Hib, yet as a retired controls designer I recognize a faulty design.
Especially one w/ same MO over all years of LS7 production.
Had QC/manufacturing process been 'fixed' why'd the problem persist?
Many newcomers considering Z06/LS7 who're aware an issue exists w/ LS7 heads et al come here always asking the same question.
Paraphrased, 'Any MY LS7 where valve issue was rectified?'[/i][/i] Same answer Hib, no.
All LS7s are subject to this failure, common sense dictates GM's designers got geometry wrong from get-go.
GM claims there's nothing whatsoever wrong w/ LS7 or its heads, what say you?
So if present design was OK why would you speculate GM redesigned heads for their 'new' LS7?
Interesting side note is on the Chevy performance website they recommend Mobil 1 15W50 engine oil for the LS7/570. My manual recommends Mobil 1 5W30 for the LS7. I don't know a lot about oil, but maybe because its a wet sump vs dry sump?
im not sure if its true but i heard all euro spec Ls7 were filled with 0W40 from factory
as a matter of fact all z06/zr1 from 2019 on were filled w/ 0W40 in europe
It was more than that Hib. GM cheaped out on the TI intake valve stem finish too. There's been a ton of cases where geometry had been corrected and there's still been rapid guide wear due to the relatively abrasive valve stem finish. Tumbling the intake valves was a band-aide repair that never really fixed the real problem. That's the main reason that your buddy (lol) Katech replaces all OEM intake valves with their moly coated TI valves.
i thought it was the exhaust valves not the intake valves that had the issue. No one really knows. My guess is it either is a geometry issue in the design or user error when the driver is wringing it out in 3rd and shifts to 2nd instead of 4th causing a hard mechanical over rev. The car runs fine for quite a while and then kaboom. And the owner doesn’t remember the Wrong shift incident or blocks it out of their mind.
06-15-2020, 12:44 PM
New LS7 from GM
