Z/28 Heads

[serviceguy]

I gotta believe if we could get a hold of the engine builders they should know. I'm assuming they built the Z06 engines.

[Unreal]

Originally Posted by blessedhellride

Thanks Dr. Chill, this is great news!!!

It is also complete BS.

Go read on CF if you want your head to spin (or not drop a valve). There is so much info you will get lost. It looks like GMs head supplier did a crap job machining heads (on all years, not just what GM said in there dumb press release). If you are going to mod, I would check the heads every 5k miles or so for wear. If it is stock, keep it bone stock and enjoy the warranty. Cost to "fix" the heads is ~1000 in parts. It is an easy swap so you can do it yourself, or a shop is about $600-700 in labor, so quotes of $4k-7k is crazy, it can easily be fixed by a shop for <2k.

[Unreal]

Originally Posted by serviceguy

I gotta believe if we could get a hold of the engine builders they should know. I'm assuming they built the Z06 engines.

They take the heads out of a bag, and bolt them onto the car. There are several on Corvette forum. The heads come preassembled from supplier, all machined and ready to go. So no, they don't know and there is no sign that is fixed since there have been 2013s with <5k on them with shot valve guides.

[Unreal]

Originally Posted by Dutchman427

Richard @ West Coast Cylinder Heads did mine and he did one hell of a job. Great guy to deal with and if you have questions, he will answer them. I know I didn't pay $900 dollars to get them ported! It was quite a bit more! When I called about getting my LSA heads ported this past month, it runs about $1,725.00.

To fix the issue, is ~$900 for valves/guides. Now when you start adding porting/etc the price goes up, but that is performance work which isn't needed at all. Now I would get it done, but if your goal is just a reliable car, then it really is ~$900 in parts/labor, plus head gaskets/fluids comes out to ~$1000 all said and done.

[blessedhellride]

I tried to look online for high mileage ls7 engines and like in some above post, I couldnt find one 100000+ mile ls7. The head issue is disconcerting......

[macalot]

Originally Posted by blessedhellride

I tried to look online for high mileage ls7 engines and like in some above post, I couldnt find one 100000+ mile ls7. The head issue is disconcerting......

Surely there can't be but a few, if any, ls7's that get driven enough to have 100,000 miles on it regardless of the year built.

[Unreal]

A few? Last time someone ran the numbers, it was ~90%, with a lot of failures. So if you consider that a few, I guess you can say that. They stopped tracking because it was obvious that almost all were effected and only a few got lucky to get a good set of heads.

That being said, if you just dropped $65k+ on a new z28, you can swing the $900-2000 to have the heads fixed when out of warranty.

[Unreal]

A few? Last time someone ran the numbers, it was ~90%, with a lot of failures. So if you consider that a few, I guess you can say that. They stopped tracking because it was obvious that almost all were effected and only a few got lucky to get a good set of heads.

That being said, if you just dropped $65k+ on a new z28, you can swing the $900-2000 to have the heads fixed when out of warranty.

[bptman]

Hi bptman here. The really sad point is I have tried to speak with GM on several topics of concern with the Z28. Not one freaking person Whom I spoke with new Jack shi## about this car. I got several phone messages with bullcrap answers like my dealer is my best source for information on that topic. Really?? did your folks not build the car?? My dealer thinks a bar is a place to have a beer. And every noise you hear is normal for the Ls7. Howsabout a conversation with a person whom knows just a little bit of usefull information. Al Openwhatever. Said this ls7 was tested countless hours at W.O.T. with No failures. Well looks like ya have to putum in a car to get them to blow up! OR maybe the car is pushing the motor with the throtle plates closed. Worn Valve guides will smoke at resting start and on decel with the throtle plates closed. And are noisey er then the normal. This is a warning sign for a future failure. Anyone of you guys have this condition or heard of any gen5 Z28 owners whom did? I just think people whom spend good money for the GM performance cars should have a resource for technical information. Its just Good to have a source the right information. Or Just buy the freaking Book!

[Mister Will]

Originally Posted by blessedhellride

I tried to look online for high mileage ls7 engines and like in some above post, I couldnt find one 100000+ mile ls7. The head issue is disconcerting......

A CF.com member just sold his '07 C6Z06 with 190,000 miles. He did not have head issues.

My club has approximately 7 C6Z06 owners. Only one had a sticky valve.

[Unreal]

Originally Posted by Mister Will

A CF.com member just sold his '07 C6Z06 with 190,000 miles. He did not have head issues.

My club has approximately 7 C6Z06 owners. Only one had a sticky valve.

Sold my stock motor to a guy that dropped a valve at 18k miles and another at 35k. My guides intake and exhaust were shot at 18k. Friend Randy dropped one at 22k. Friend Don had guides 4x the service spec at 20k miles. Tony, guy down in Tucson dropped a valve last month in his 07. Friend of mine AJ was so worn that one of the valves started forming a radial crack around the head. He caught it just in time. Out of 18-19 z06s I know, one has checked out ok as far as guide wear, and I know several people who have dropped valves, and even saw my friend Randys car do it right in front of me.

So yes, there are a few cars out there with 100K+ miles, and there are cars out there with <10k with issues. That is why it is important to check the guides every ~10k miles, and then replace when needed. If you check at 10k, 20k, 30k, 40k and no wear you probably lucked out with a good set, but if not pull the heads and fix them. Guy on CF checked fine at 15k, checked again a year later, all out of spec. Only takes an hour or two to check. Just figure it is part of owning a LS7 motor.

That or be proactive and just swap the heads, port them, and enjoy better reliability and more power.

[KaBoom1701]

Originally Posted by Unreal

Sold my stock motor to a guy that dropped a valve at 18k miles and another at 35k. My guides intake and exhaust were shot at 18k. Friend Randy dropped one at 22k. Friend Don had guides 4x the service spec at 20k miles. Tony, guy down in Tucson dropped a valve last month in his 07. Friend of mine AJ was so worn that one of the valves started forming a radial crack around the head. He caught it just in time. Out of 18-19 z06s I know, one has checked out ok as far as guide wear, and I know several people who have dropped valves, and even saw my friend Randys car do it right in front of me.

So yes, there are a few cars out there with 100K+ miles, and there are cars out there with <10k with issues. That is why it is important to check the guides every ~10k miles, and then replace when needed. If you check at 10k, 20k, 30k, 40k and no wear you probably lucked out with a good set, but if not pull the heads and fix them. Guy on CF checked fine at 15k, checked again a year later, all out of spec. Only takes an hour or two to check. Just figure it is part of owning a LS7 motor.

That or be proactive and just swap the heads, port them, and enjoy better reliability and more power.

Screw that. Who has the time to do a 2-3 hour check every 10k?

I'd just pay a shop the 2k and fix the issue. How much does it really cost to just fix this and be done with it?

[Unreal]

$1000 in parts, and 6-7 hours labor. So $1000 if you DIY, or $1700-1800 if you pay a shop. The higher quotes are when you start adding a bunch of performance stuff, like porting, cams, springs, pushrods, chain, etc. None of that is needed to fix the issue, but it isn't a bad idea to do it while you are in there.

[blessedhellride]

Originally Posted by Unreal

$1000 in parts, and 6-7 hours labor. So $1000 if you DIY, or $1700-1800 if you pay a shop. The higher quotes are when you start adding a bunch of performance stuff, like porting, cams, springs, pushrods, chain, etc. None of that is needed to fix the issue, but it isn't a bad idea to do it while you are in there.

Agreed