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GM LT6 - all-new DOHC 8600-rpm aspro 5.5L V8


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#1 Almag

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Posted 05 November 2021 - 20:55

So, the latest V8 for the Corvette Z06 appears to be quite something. Flat-plane crank, 8600 rpm, normally aspirated, dry sump, 670 hp. It's as though GM wanted to build an engine to out-Ferrari Ferrari. Notable as it's almost certainly the last clean-sheet performance engine the General ever produces.

 

One detail that stands out to me - the finger follower valvetrain never requires adjustment (!). I am struggling with this a bit. Perhaps the cam/follower/shims never wear (DLC coating), but how is it possible that the valve seats never wear? Or rather, that they don't wear enough within the engine's service life to necessitate a valve adjustment. 

 

Anybody have insights into this?



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#2 Greg Locock

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Posted 05 November 2021 - 22:27

Toyota introduced an adjusted for life valve train a while back. Basically the valve seat erosion is matched to the (something or other change over time) so it all stays in spec.



#3 Magoo

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Posted 06 November 2021 - 02:39

This is a continuing trend. Many engines without hydraulic lash mechanisms can go 100K+ without valvetrain adjustment these days, The Corvette may be novel as a relatively high-rpm engine with this capability, but I don't know that. I would have to look around. 



#4 Wuzak

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Posted 08 November 2021 - 06:13

It's as though GM wanted to build an engine to out-Ferrari Ferrari. 

 

They are about 10 years too late!



#5 kikiturbo2

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Posted 08 November 2021 - 09:00

This is a continuing trend. Many engines without hydraulic lash mechanisms can go 100K+ without valvetrain adjustment these days, The Corvette may be novel as a relatively high-rpm engine with this capability, but I don't know that. I would have to look around. 

porsche makes a gt3/RS engine that revs to 9 and has solid valvetrain.. I doubt it needs regular adjustment..



#6 Almag

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Posted 09 November 2021 - 02:23

Yes, GT3 engine has been this way for a few years, as it turns out.

Still puzzling over how is valve seat wear accommodated.

#7 Greg Locock

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Posted 09 November 2021 - 03:40

That information is out there. Your google skills probably match mine.



#8 kikiturbo2

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Posted 09 November 2021 - 10:00

valve tip wear vs seat wear?



#9 MatsNorway

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Posted 15 November 2021 - 18:50

I am sure it is great and all. But is it more performance for the buck? Is it not just another McLaren/Ferrari V8 thing?  The new Corvette being mid engine and now having a wasp engine makes it less interesting for me. I guess i am getting old :p Give me a decade and i might have adjusted.


Edited by MatsNorway, 15 November 2021 - 18:50.


#10 kikiturbo2

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Posted 22 November 2021 - 08:43

Yeah, I like the old 7 litre LS7 ZO6 too..: :D

 

But, people like the exotic element.. Otherwise everyone would be buying the 911 Turbo s... This way they cant make enough of the 9000 rpm GT3's