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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
No brother, I think I snapped a clutch disc off the hub. So I have been debating which Way I am going to remove and Re-install ... whether it's remove the engine or remove the rear end.
I am leaning more towards removing the engine (again) to do a clutch job. So I don't have to remove the rear end (on the ground again) I am about to pull the trigger on Tony's ported oil pump setup and redesigned ATI balancer.
And I want to have the freedom to work on the engine on an engine stand instead of hunched over.
Reading through this thread and read a few other articles about the head issues, I bought a 2007 Z06 with roughly 115,000 kms or 72,000 miles for you US friends. My question is this, I purchased this vehicle off a older gentlemen (snow bird) who drove it to and from Alberta, Canada to Phoenix every year until he could no longer get in and out of it. The car was driven very light its whole life (completely stock with a ton of highway miles), I too don't drive it very hard so my question is am I also at high risk for head issues?
I have heard a lot about problems occur as the car is modded, driven hard (Track, drag, etc). It was just a cruiser for him and now me? Second question is there any way I can check the condition of my heads?
I am no mechanic by any means, and finally was able to save up enough to buy this dream? But now I need to know if I should be dropping $$ into new heads and track guides or if I am ok?
^^^^Hello, and welcome! To answer your question very directly, IMO all 2006 to present LS7 engines are susceptible to the valve guide problem. It does not matter how your car was driven, and frankly you have no idea how it was driven except what you have been told. If you re-read my post #2 in this thread, I explain my personal experience with the valve guide issue. My car was defective from the factory, the day the engine was built it had bad heads on it; could I have driven 72K miles without a failure, maybe, maybe not. If the car is not burning oil, or making abnormally load valve train noise you may be OK; the only way to know is to measure to tolerances, or wait until it fails. The fact that you are at 72K miles with no catastrophic failure yet means nothing in regard to having less of a tendency for failure.
By the way, the 2007 LS7's had an issue with the needle bearings in the rocker arms, that is something you should run to ground, although if they have not failed by now they may not, however again good to check it out.
Reading through this thread and read a few other articles about the head issues, I bought a 2007 Z06 with roughly 115,000 kms or 72,000 miles for you US friends. My question is this, I purchased this vehicle off a older gentlemen (snow bird) who drove it to and from Alberta, Canada to Phoenix every year until he could no longer get in and out of it. The car was driven very light its whole life (completely stock with a ton of highway miles), I too don't drive it very hard so my question is am I also at high risk for head issues?
I have heard a lot about problems occur as the car is modded, driven hard (Track, drag, etc). It was just a cruiser for him and now me? Second question is there any way I can check the condition of my heads?
I am no mechanic by any means, and finally was able to save up enough to buy this dream? But now I need to know if I should be dropping $$ into new heads and track guides or if I am ok?
Appreciate your opinions!
opposite actually - most failures are with people that drive them easy and lug the engine. Tracking them and driving them hard keeps the valve stems lubricated.
^^^^Hello, and welcome! To answer your question very directly, IMO all 2006 to present LS7 engines are susceptible to the valve guide problem. It does not matter how your car was driven, and frankly you have no idea how it was driven except what you have been told. If you re-read my post #2 in this thread, I explain my personal experience with the valve guide issue. My car was defective from the factory, the day the engine was built it had bad heads on it; could I have driven 72K miles without a failure, maybe, maybe not. If the car is not burning oil, or making abnormally load valve train noise you may be OK; the only way to know is to measure to tolerances, or wait until it fails. The fact that you are at 72K miles with no catastrophic failure yet means nothing in regard to having less of a tendency for failure.
By the way, the 2007 LS7's had an issue with the needle bearings in the rocker arms, that is something you should run to ground, although if they have not failed by now they may not, however again good to check it out.
Thanks for the info, I don’t hear anything nor does it burn any oil? Is there any other way to get the dealer to check them out? I was reading some guys had got them tested for measurement or what ever?
Originally Posted by Apocolipse
opposite actually - most failures are with people that drive them easy and lug the engine. Tracking them and driving them hard keeps the valve stems lubricated.
GM used to approve of the "wiggle" test, but not any longer. You can do it yourself and if you do a search on this Forum you will see some examples. The dealer may or may not want to pulls the heads and check them for you, some are not even aware of the problem.
Thanks for the info, I don’t hear anything nor does it burn any oil? Is there any other way to get the dealer to check them out? I was reading some guys had got them tested for measurement or what ever?
Are u serious? I thought the opposite!
Ya I am serious - lugging these engines is no bueno. The valve seals do their job too well at low easy rpms.
I agree with Apocolipse about lugging the engine being bad in any situation. But driving easy creates a high vacuum in the intake port. That should lube the guides well, especially considering the lower revs. However, Appcolipse is also correct about higher rpm, because when you let off the throttle at higher rpm, that creates the highest vacuum the engine will ever see. BUT-It isn't that simple. At high rpm you are also working the valves very hard as far as surface feet per minute. A valve stem sliding up and down 50 times per second will wear a guide and stem more than an engine that that's cruising at 1,700rpm, so that's also part of the equation.
On this valve stem lubrication topic, I seem to recall having read that AHP guides have a spiral (rifling?) cut into them to help keep valve stems lubed and happy.
I could be wrong…
On this valve stem lubrication topic, I seem to recall having read that AHP guides have a spiral (rifling?) cut into them to help keep valve stems lubed and happy.
I could be wrong…
Not sure exactly where to start from but here goes…..
This is my 3rd C6 and somewhat versed in relation to modifying high performance vehicles however I have never modified any of my C6’s including LS2 and LS3 cars. I purchased this C6 Z06 approximately 9 months ago with 31000 miles on it. The car is completely stock with the exception of a cold air intake system developed by Halltech (Killer Bee System).
The internet is plastered with information on the LS7 heads in which some have grenaded the mill due to the faulty cylinder heads and some have gone 100,000 miles with no issues.
Given that it took me a while to find the car in my favourite colour I don’t foresee selling it in the near future, For this reason I am thinking of doing the heads. The first reason would be so I don’t become a statistic and the other would be adding more POWA while looking stock and sounding stock.
My initial plan was to port and mill the factory heads and while doing so port out the factory intake manifold. I really liked this idea as the car would look completely stock and I would notice strong gains with the porting/milling along with the halltech and a dyno tune.
However I am wondering if purchasing aftermarket heads is the way to go? In saying that I would like to do the most cost effective way to reach my goals.
Guess I should note my goals. The car as it sits makes great power and pulls nicely. I don’t have any power goals sort to speak but with the mods mentioned 50 hp and 30 tq would be a nice power bump while running stock exhaust manifolds.
Brings me to this…..
Is it worth porting out the factory manifold while opening up the cylinder heads or is this a waste of money?
If I stay with the factory heads who would you have port them and what hardware would you have installed?
Some of you would say to install headers however at this time I would like to keep the factory appearance while adding more power. In saying that if I find a good deal on headers I may go that route in the future.
Below are two pictures of the car. I recently switched out my chrome wheels for painted oe wheels and absolutely love the look.
Any suggestions, and comments are
I have the same cyber gray on my 09z with black spider design rims! Love it to death!
I have the same cyber gray on my 09z with black spider design rims! Love it to death!
I’m Batman
NEVER mention death when discussing LS7 valve drops!!!! LOL.
FWIW.....I have now accumulated over 25,000 miles on my AHP fixed heads. Ive also hit the 48,000 mile mark on my PAC dual springs. I have a new set waiting on the bench, and will be changing the springs within the next month. At that time, I'll inspect whatever wear there may be on the guides. When AHP did the heads, they installed the hardened PM guides, FWIW. As of now, the engine has 48,000 miles on it, and uses no oil between changes, with changes being 5,000 miles. I'll report back what I find, if anything. Actually, I'm more concerned about how my near 70 year old back will hold up more than how Kohle's guides have held up!!!
NEVER mention death when discussing LS7 valve drops!!!! LOL.
FWIW.....I have now accumulated over 25,000 miles on my AHP fixed heads. Ive also hit the 48,000 mile mark on my PAC dual springs. I have a new set waiting on the bench, and will be changing the springs within the next month. At that time, I'll inspect whatever wear there may be on the guides. When AHP did the heads, they installed the hardened PM guides, FWIW. As of now, the engine has 48,000 miles on it, and uses no oil between changes, with changes being 5,000 miles. I'll report back what I find, if anything. Actually, I'm more concerned about how my near 70 year old back will hold up more than how Kohle's guides have held up!!!
03-15-2023, 07:06 AM
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