LS6 testing?
Thread Starter
Instructor
Joined: Aug 2025
Posts: 168
Likes: 57
LS6 testing?
Any idea what kind of testing was done on the new engine? It sounds awesome but is really unproven (production wise) regarding the 13:1 compression ratio and other nuances like the induction system and new lubrication setup. As the car is produced and sold miles driven will reveal any issues if there are any? I read this small block will also be used in their truck lines but not sure if it will be a 13:1 version in a truck. Could be? The LT2 seemed to be a good reliable engine. I’m guessing GM wouldn’t provide a warranty unless they felt good about it. But they warranted lots of truck engines that had AFM liter issues that were expensive to fix, if they fixed them at all. Many horror stories about not honoring warranty for lifter failures. That never seemed to be a huge issue for the Corvette engines. I read the new AFM system was moving away from the lifters to hydraulic rocker arms. All this stuff has to work reliably including the direct and port injection. Like I said the new engine sounds awesome! Just hope all the design features have been adequately vetted.
Burning Brakes
Joined: May 2025
Posts: 797
Likes: 602
From: Bucks County, PA
Any idea what kind of testing was done on the new engine? It sounds awesome but is really unproven (production wise) regarding the 13:1 compression ratio and other nuances like the induction system and new lubrication setup. As the car is produced and sold miles driven will reveal any issues if there are any? I read this small block will also be used in their truck lines but not sure if it will be a 13:1 version in a truck. Could be? The LT2 seemed to be a good reliable engine. I’m guessing GM wouldn’t provide a warranty unless they felt good about it. But they warranted lots of truck engines that had AFM liter issues that were expensive to fix, if they fixed them at all. Many horror stories about not honoring warranty for lifter failures. That never seemed to be a huge issue for the Corvette engines. I read the new AFM system was moving away from the lifters to hydraulic rocker arms. All this stuff has to work reliably including the direct and port injection. Like I said the new engine sounds awesome! Just hope all the design features have been adequately vetted.
Race Director
Joined: Dec 2006
Posts: 12,358
Likes: 2,893
From: Fort Worth, Texas
Any idea what kind of testing was done on the new engine? It sounds awesome but is really unproven (production wise) regarding the 13:1 compression ratio and other nuances like the induction system and new lubrication setup. As the car is produced and sold miles driven will reveal any issues if there are any? I read this small block will also be used in their truck lines but not sure if it will be a 13:1 version in a truck. Could be? The LT2 seemed to be a good reliable engine. I’m guessing GM wouldn’t provide a warranty unless they felt good about it. But they warranted lots of truck engines that had AFM liter issues that were expensive to fix, if they fixed them at all. Many horror stories about not honoring warranty for lifter failures. That never seemed to be a huge issue for the Corvette engines. I read the new AFM system was moving away from the lifters to hydraulic rocker arms. All this stuff has to work reliably including the direct and port injection. Like I said the new engine sounds awesome! Just hope all the design features have been adequately vetted.
Drifting
Joined: Jul 2017
Posts: 1,361
Likes: 1,334
From: Kingston, Ontario
Do you think manufacturers make engines and don't test them? They have to honour a 5 year powertrain warranty. They would lose their shirt on them if they made a new engine with barely any testing. Production engines see tons of miles during R&D.
I'm not saying they will be perfect but you have a warranty if it has issues and if not you can wait a few years for any problems to be ironed out if you don't want to be an early adopter.
I'm not saying they will be perfect but you have a warranty if it has issues and if not you can wait a few years for any problems to be ironed out if you don't want to be an early adopter.
Team Owner
Joined: Aug 2006
Posts: 24,653
Likes: 1,180
From: Raleigh
I hope it was tested better than the 2001 z06 LS 6 was. Buying a first year car that was tagged as an “ oil burner “ then having the fix and a 20 HP bump the next year taught me to never buy a first year GM engine.
Drifting
Joined: Aug 2017
Posts: 1,883
Likes: 352
From: Dayton, OH
I was in a test lab as a customer on an aerospace project and saw an engine undergoing extensive physical environmental (Climactics and dynamics) testing. They had to chase me away several times and wouldn't tell me what it was.
Turns out it was the LS9.
Turns out it was the LS9.
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Race Director
Joined: Oct 2008
Posts: 16,628
Likes: 7,706
From: NJ
I get what the op is saying. One strange thing I noticed on the LS6 is the fuel injectors are going though the valve cover? So another 4 seals per side that can leak on a simple valve cover? Still using ohv tech but beginning to get as complicated as a dohc without the benefits. Weird.
It does not appear that Mfrs design these types of ultra hi performance engines to last the life if the car just maximize what they can and meet emissions and mpg goals. They make sure it'll make 100k mi and call it a day. In a vette? Wont be an issue. Let's see how the truck engines do.
So many examples of this over the years. LS7. 8 speed auto trans in C7s (and all other gm vehicles that had them) took them 4yrs to figure out how to stop the trans fluid formula to stop retaining moisture and causing issues? The cardboard tough 4L60e trans?
I'm sure it'll be fine given the history with LT1 and LT2 I'm more interested in how the new dfm works vs the lifter based afm that causes so many problems in the truck side.
Race Director
Joined: Aug 2019
Posts: 12,351
Likes: 14,182
From: Central Illinois
Shame on GM for not making the car 100% idiot proof. It was operator error. There are thousands of fueling fires each year, not just Z06s. Almost invariably it was operator error. I gas mine frequently (not exactly economy based) and have zero anxiety while fueling. No, I don't have the recall performed yet either, don't care if I ever do since I know how to fuel the car.
Race Director
Joined: Oct 2008
Posts: 16,628
Likes: 7,706
From: NJ
Shame on GM for not making the car 100% idiot proof. It was operator error. There are thousands of fueling fires each year, not just Z06s. Almost invariably it was operator error. I gas mine frequently (not exactly economy based) and have zero anxiety while fueling. No, I don't have the recall performed yet either, don't care if I ever do since I know how to fuel the car.
The point is, they make PLENTY of mistakes even though they test them for hundreds of thousands of miles and for years. It's crazy to me that some of these things (like the fluid in the 8spd trans debacle and the oil leaks and ticking of LT6 AND the original design if the DCT that required another couple quarts!) dont get picked up.
Ill even go one further, the 15 and 16 Z06 didnt come with side skirt deflectors as stsndard equipment and gm was repainting Z06 quarter panels left and right until 17 when they made them standard. Yet they were driving that thing around for how long?
And it isnt like history doesn't repeat itself when you dont learn from it. They knew this going back as far as 1970.
These redesigned, slightly wider, and more flared lower fender edges were intended to reduce damage to the rear fender and rocker panel paint caused by stones and debris thrown up by the front tires.
In other words I applaud the engineers but they're not gods.
One more
Thr 500mi LT1 oil change requirement.
Let's not forget that impotant one.
Racer
Joined: Jul 2025
Posts: 403
Likes: 232
From: Evansville(ish) Indiana
I don't think it is even possible for GM to test what will happen once the engines are in git-er-dun mass production mode instead of tender loving care initial production mode.
If such a thing could be done then 1st generation Ford 3.5 turbo's in the F150's wouldn't be feared due to turbo failure issues and the 2nd generation wouldn't be feared for cam phasor issues and you wouldn't pull up an entire list of problems when you do a web search for "GM pickup truck transmission issues" .
Ford took care of me when I had the cam phasor issue (paid $5000 of a $6000 bill when the truck was past warranty). GM seems to be screwing folks with at least one of the truck transmission issues (extending warranty instead of fixing the problem).
Hopefully the new engine won't bring any gremlins along.
If such a thing could be done then 1st generation Ford 3.5 turbo's in the F150's wouldn't be feared due to turbo failure issues and the 2nd generation wouldn't be feared for cam phasor issues and you wouldn't pull up an entire list of problems when you do a web search for "GM pickup truck transmission issues" .
Ford took care of me when I had the cam phasor issue (paid $5000 of a $6000 bill when the truck was past warranty). GM seems to be screwing folks with at least one of the truck transmission issues (extending warranty instead of fixing the problem).
Hopefully the new engine won't bring any gremlins along.
Race Director
Joined: Oct 2008
Posts: 16,628
Likes: 7,706
From: NJ
I don't think it is even possible for GM to test what will happen once the engines are in git-er-dun mass production mode instead of tender loving care initial production mode.
If such a thing could be done then nearly every 1st generation Ford 3.5 turbo in the F150's wouldn't have turbo failure issues and nearly every 2nd generation wouldn't have cam phasor issues and you wouldn't pull up an entire list of problems when you do a web search for "GM pickup truck transmission issues" .
Ford took care of me when I had the cam phasor issue (paid $5000 of a $6000 bill when the truck was past warranty). GM seems to be screwing folks with at least one of the truck transmission issues (extending warranty instead of fixing the problem).
Hopefully the new engine won't bring any gremlins along.
If such a thing could be done then nearly every 1st generation Ford 3.5 turbo in the F150's wouldn't have turbo failure issues and nearly every 2nd generation wouldn't have cam phasor issues and you wouldn't pull up an entire list of problems when you do a web search for "GM pickup truck transmission issues" .
Ford took care of me when I had the cam phasor issue (paid $5000 of a $6000 bill when the truck was past warranty). GM seems to be screwing folks with at least one of the truck transmission issues (extending warranty instead of fixing the problem).
Hopefully the new engine won't bring any gremlins along.
Probably will. They changed enough to suggest it. Whereas the LT2 was almost identical to LT1 so the bugs were worked out. We are the test bed for the mfrs the days of Lexus and toyota Honda type reliability have been over (even in those brands)
Melting Slicks
Joined: Nov 2013
Posts: 2,702
Likes: 984
From: Annandale VA
And don't forget that the new 6.7 will be built at the brand new Flint engine plant where engines haven't been built for 20 years. All the workers must be trained and certified as well as all the tools and equipment. Could be some serious problems given the lack of experience.
Race Director
Joined: Oct 2008
Posts: 16,628
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From: NJ
And don't forget that the new 6.7 will be built at the brand new Flint engine plant where engines haven't been built for 20 years. All the workers must be trained and certified as well as all the tools and equipment. Could be some serious problems given the lack of experience.