Corvette magazine take on c6z06 reliability issues
02-12-2018, 09:15 PM
#21
Le Mans Master
If there is an issue with the valves not being concentric with the valve seats, I would say that is a design issue, not necessarily a machining issue. I'm guessing that is a different issue than the machining problem they identified and said they corrected. But I could be wrong, I'm no expert. All we can agree on is that there are still issues with excessive valve guide wear even after they said they corrected the machining error, which tells me there are other issues involved.
This mystery was solved long ago..
Last edited by Dan_the_C5_Man; 02-12-2018 at 09:18 PM.
02-12-2018, 09:22 PM
#22
Team Owner
Last edited by MTPZ06; 02-12-2018 at 09:23 PM.
02-12-2018, 09:28 PM
#23
Race Director
If there is an issue with the valves not being concentric with the valve seats, I would say that is a design issue, not necessarily a machining issue. I'm guessing that is a different issue than the machining problem they identified and said they corrected. But I could be wrong, I'm no expert. All we can agree on is that there are still issues with excessive valve guide wear even after they said they corrected the machining error, which tells me there are other issues involved.
Most head companies install and hone the guides and then use the guide as the guide for the tool to machine the seats, assuring concentricity.
Last edited by AzDave47; 02-12-2018 at 09:29 PM.
02-15-2018, 12:18 PM
#25
Pro
Thread Starter
Yeah, thats my main point, disservice not mentioning the glaring issues, recall of fuse box for headlights, ie. They didnt have to go into detail for that article, but at least mention them.
Not everyone that owns c6z06 reads this forum or even gets mailings if purchased used.
Not everyone that owns c6z06 reads this forum or even gets mailings if purchased used.
02-15-2018, 12:53 PM
#26
Le Mans Master
Linimar uses a CNC machine to do the guides and do the seats separately, thus poor programming yields non-concentric valves/seats.
Most head companies install and hone the guides and then use the guide as the guide for the tool to machine the seats, assuring concentricity.
Most head companies install and hone the guides and then use the guide as the guide for the tool to machine the seats, assuring concentricity.
02-18-2018, 05:44 PM
#27
Safety Car
So many "experts" on machining. The guides and seats are machined at the same time with the same tool. Period. The issue comes from the guides. The inner ID isn't concentric with the outer OD. The drill and reamer follow the hole.
02-18-2018, 06:54 PM
#29
Race Director
You are correct that normal aftermarket valve work installs the guides, hones them and then use the guides to cut the valve seats, assuring the valves are concentric with the seats.
02-18-2018, 10:23 PM
#31
Race Director
GM doesn't do the LS7 heads, their contractor Linimar delivers them finished and assembled to the Vette plant in KY. It is not GMs messup (other than lack of oversight and QC).
02-22-2018, 01:47 PM
#35
Pro
Thread Starter
No. I have an 07 an my guides were outta spec. Id have them checked, but no reason to not look for a car. Any car should be checked if they havent been addressed already.