Long Term Ownership and Durability

[hjdca]

Originally Posted by quickdrraw

I lol at everyone worried about the LS7 issue. This has been fixed since 2012 and Chevy posted a bulletin about it. It took me half a second to search for answers. The issue was one of Katech's suppliers, fixed long ago. Sorry to the guy who tore his motor apart because of worry, hopefully you were planning to build it anyways.

yes, I believe this is correct. The issue was not a design flaw, but, "out of spec" parts (valve guides, Valve stems, etc...) Once this was found, they tracked down the offending CNC machine and fixed it/replaced it around 2012. It should have been an easy fix. Everything else just seems to be noise.

[Lightsaber]

Originally Posted by hjdca

yes, I believe this is correct. The issue was not a design flaw, but, "out of spec" parts (valve guides, Valve stems, etc...) Once this was found, they tracked down the offending CNC machine and fixed it/replaced it around 2012. It should have been an easy fix. Everything else just seems to be noise.

So can we make an umbrella assumption that all Z28's made after that (2013, 2014, 2015 model years) are free of the dropped valve issue?

[joelster]

Originally Posted by Lightsaber

So can we make an umbrella assumption that all Z28's made after that (2013, 2014, 2015 model years) are free of the dropped valve issue?

It would seem so unless the plant had a lot of LS7 heads laying around as extra inventory that were built prior to 2012.

Also there have been a few Z/28 engine failures and a few guys that have claimed to have measured Z/28 heads and found them out of spec.

My car has 5700 miles and has been tracked 3 times. No issues here.

[Spurshot]

If I were planning to keep a Z28 "forever", I'd stock up on the carbon rotors.

[macalot]

Originally Posted by Spurshot

If I were planning to keep a Z28 "forever", I'd stock up on the carbon rotors.

If you are not going to track the car the original rotors will last just about "forever".

[gringo]

Originally Posted by Spurshot

If I were planning to keep a Z28 "forever", I'd stock up on the carbon rotors.

Stock up? You do realize those carbon ceramics go for a small $$$$ mint. That's why some guys, who race a lot, switch them out for less expensive options.

[BUBZ28]

I read on here that the caliper bolts are one time use only. What do the guys who switch back and forth between CCM and steel rotors do? New bolts each time?

[quickdrraw]

Originally Posted by BUBZ28

I read on here that the caliper bolts are one time use only. What do the guys who switch back and forth between CCM and steel rotors do? New bolts each time?

[MrRaZ28]

The answers always vary. Most just loctite and go a certain torque. I bought some for when I swapped mine, but the part number for the rears gave me the wrong bolts and I had no choice BUT to loctite them. So far no issues. I have checked and rechecked, and so far they haven't backed out. I don't like it but until the dealer can figure out why the part number didn't match up this is what I've got. I'm not tracking for a while so I should be okay.

[1970judge]

Originally Posted by BUBZ28

I read on here that the caliper bolts are one time use only. What do the guys who switch back and forth between CCM and steel rotors do? New bolts each time?

Straight from the service manual. I post it every time it is brought up.

[hjdca]

Originally Posted by hjdca

fyi, I am using magnetic oil drain plugs (Gold plug). Here are some pictures of the magnetic drain plugs at around 9K miles with around 3.5K street miles on the oil. The minuscule metal sticking to the magnet seems normal. I am changing the oil again soon, so, I will post more pics. So far, so good.

Pick of dirty and cleaned oil plug




Here you can see the super small metal shavings.

Here is an update to my Gold Plugs during oil change. I just did my 4th oil change with approx. 3500 street miles on this oil in the Z/28. Any minuscule magnetic particles have decreased roughly 75% since the last oil change. it is kinda hard to see because of the shadow, but, you can see on the paper that cleaning off the magnets yielded much less material. It seems the engine is fully broken in and the motor is running great ! So far, so good !

[NVNO1]

Originally Posted by joelster

Agreed.

Look at all of the guys posting with 35,000+ miles on their cars. No issues. If the valve guides were bad and out of spec, or soft or whatever, then those engines would have some serious noises coming from under the hood. There's no way it will affect some cars within 500 miles, while other cars will run forever.

I don’t think you would be lol if your engine dropped a valve and destroyed your motor. Where is this “bulletin” Chevy posted? As I posted above I have not seen any proof nor have I seen Chevy admit to or address, change or fix the head issue in 427s. If there is something I’d sure like to see it. I sure doubt Chevy would admit to there being a problem. There is a class action law suit against Chevy for the dropped valve issue. It’s on the corvette forum. Quite a few people are apart of this law suit due to engines blowing up due to dropped valves. If seen so many posts stating “I think they” “I heard they”....where is the proof the heads have been fixed or changed on the Z/28?
Mileage doesn’t matter. The way you use you car doesn’t matter. Some heads are clearly more “out if spec than others”. Can you drive your car 30, 40 even 100k miles and not have a problem? Yes. On the other hand 427 motors have dropped valves and destroyed engines with less than 500 miles on the car.
Food for thought. My neighbor has a 07 Z06. He treats that his car like absolutel sh!t. It’s absolutely trashed. Never does routine maintenance etc. has 50k something miles on it with no problems.
Mine Z06 is an 09 with Les than 6k miles on it and maintainined to the absolute highest standards. My car is absolutely flawless not a swirl mark on it. No track, no roll ons, no drag racing never beat on. Oil always up to temp before going over 2500 rpm bla bla. Anyway dropped valve less than 6k miles on it. Your “serious noise” claim is false period. Some people are in total denial about this issue.
Call Able chevy and ask them how many 427s they have replaced because of dropped valves. Yes Z/28s are included it’s not just Z06s. That’s just one dealership. Call American Heritage Performance and ask them the same question.
Can you drive your car with the valves being out of spec? Yes. For how long it’s hard to say, but to say there is no problem is ridiculous. Way too many documented engine failures because of dropped valves. Lastly I also would love to believe Chevy “fixed” the head issue. Just haven’t seen any proof of this. Anyway back to working overtime so I can pay for my new LS7 which dropped a valve and destroy my motor.

[MrRaZ28]

Originally Posted by quickdrraw

I lol at everyone worried about the LS7 issue. This has been fixed since 2012 and Chevy posted a bulletin about it. It took me half a second to search for answers. The issue was one of Katech's suppliers, fixed long ago. Sorry to the guy who tore his motor apart because of worry, hopefully you were planning to build it anyways.

If you could link this bulletin so we have a once and for all, that'd be great.

A lot can happen in 11 years of engine building... especially since this was prevalent 7-10 years ago.. Unlike Nissan with their SMOD and transmissions and screwing their customer base over with it, I would LIKE to think GM did it right with this.

Either way, I have an extended warranty and if something blows on the engine $200 bucks and I don't worry about it. And if nothing happens by the time I'm ready to put different heads on for my build, I'm okay with that too.