Jump to content

My Heads are out of spec


ZZZ0006

Recommended Posts

Had the wiggle test done yesterday at American Heritage Performance. The heads will be rebuilt and will fly back in a couple weeks to drive her home. I am very lucky I did not drop a valve. My car is a 2008 Z06 with 27000 miles on it. Here are the measurements.

Hello Dan,

Below are your wiggle test results:

#1 int: .008"

#1 exh: .007"

#3 int: .0075"

#3 exh: .008"

#5 int: .007"

#5 exh: .0085"

#7 int: .009"

#7 exh: .007"

#2 int: .007"

#2 exh: .0075"

#4 int: .0075"

#4 exh: .0065"

#6 int: .007"

#6 exh: .0115"

#8 int: .0075"

#8 exh: .008"

These are your "raw" wiggle test measurements. The actual mic/bore measurements will be/ are roughly half of the wiggle test measurement. GM max spec is .0037" which would translate to a wiggle test measurement of around .0075" (max spec.

Link to comment
Share on other sites

Hey Dan,

Glad AH caught the problem! I see you have 27K on the clock. I'm knocking on the door w/21K myself. Did your car make any unusual sounds from the engine bay or anything like that? So far, my car seems to be quiet un like my 08Z. Best of luck to you!

Tony

Link to comment
Share on other sites

My father in law took his in at the same time,his was out of spec as well at 47000 miles on his 2006 Z06. One valve was so bad it's amazing it did not fail.

Link to comment
Share on other sites

Ive seen perfectly quiet cars drop valves.

I've only seen one car out of 20+ with guides in spec. Almost to the point where I say dont bother paying to check, just get them done.

Link to comment
Share on other sites

Ive seen perfectly quiet cars drop valves.

I've only seen one car out of 20+ with guides in spec. Almost to the point where I say dont bother paying to check, just get them done.

I agree 100%,get them checked and fixed. What are the odds of taking two different model year Z06's to a shop and both failed. Kohle at American Heritage sent us a video of one of my father in laws valves that was so bad he was amazed it had not failed yet.

Link to comment
Share on other sites

Ive seen perfectly quiet cars drop valves.

I've only seen one car out of 20+ with guides in spec. Almost to the point where I say dont bother paying to check, just get them done.

Probably some good advice there...... :bannana4:

Link to comment
Share on other sites

What's the reason for this common problem, bad material used for the guides? Or is it the geometry of the valve train?

Link to comment
Share on other sites

Hey Dan,

Glad AH caught the problem! I see you have 27K on the clock. I'm knocking on the door w/21K myself. Did your car make any unusual sounds from the engine bay or anything like that? So far, my car seems to be quiet un like my 08Z. Best of luck to you!

Tony

Sounded good at 150 MPH in 1/2 mile

Link to comment
Share on other sites

What's the reason for this common problem, bad material used for the guides? Or is it the geometry of the valve train?

People argue all the time, but it looks like bad geometry. Once you get that sorted out, guides last just fine.

Link to comment
Share on other sites

What's the reason for this common problem, bad material used for the guides? Or is it the geometry of the valve train?

People argue all the time, but it looks like bad geometry. Once you get that sorted out, guides last just fine.

I don't suppose the replacement guides and SS valves change the geometry do they? I heard it was a harmonic issue causing excessive wear. Changing the materials changes the harmonics and the issue is no longer present. But I haven't researched it thoroughly and I'm an amateur material scientist.

Link to comment
Share on other sites

Yes it does. It is guide concentricity/etc, so new guides machined properly seems to fix it. Wether those are PM, Brass, etc or stock, ss, inconel, hollow SS, Ti, if the machining isn't correct the guide will wear. Ones with new guides machined correctly seem to last. There has been PM, Brass, etc all make it 50k+ miles with no signs of wear after being reworked. As for what you do, pick whatever you want. Who does the work and their equipment seems far more important than the actual parts choosen.

If I could go back only thing I would change is I would run inconel exhaust valves instead of solid SS.

Link to comment
Share on other sites

What really pisses me off is GM not issuing a recall to check every Z06 built and if found bad replace the heads with new ones that have been triple checked for quality control. I sent a pm to username Chevrolet Cust Service yesterday, his name is William.

Here is our exchange:

Hi William-

My Father in Law and I took both of our Z06's to American Heritage Performance in Harbor City, CA yesterday, both cars were tested and had several valves out of spec. I recently bought an extended warranty on my 2008 Z06, this warranty was an aftermarket warranty that I paid $ 3000.00 for through the dealer, so I am covered I believe, we are waiting for the adjuster to come by the shop. But I am still out of pocket $3000.00 out of concern with the heads, so either way I have paid for a repair - if you can compensate me in some way would be great.

My Father In Law Bob M. has a 2006 Z06 with 47,000 miles on his car, he has no warranty left. One of his exhaust valves was so bad and out of spec that it was not sealing in the guide and is very lucky it did not drop and ruin his motor. Will Chevy/GM help out on his repair? It is going to cost my Father In Law $ 2600.00 + Tax to have American Heritage Performance R&R, rebuild his heads with machining, new guides, seals, and valves. If so could you contact Kohle at American Heritage at 310-906-6222 and let him know what you can do? Any help would be appreciated.

$ 70,000.00 cars and having this well known issue is frustrating to say the least. I do have to say I am really upset in the fact that GM will not issue a recall on this issue with these improperly machined heads from Linamar, do we Corvette Owners need to file a lawsuit to get GM to finally issue a recall??? If someone dropped a valve while driving on a crowded freeway could cause an accident and kill people.

Thanks,

Dan P.

&

Bob M.

Dan,

Thanks for your message. I'm sorry to learn that your 'Vette had several valves out of spec. American Heritage Performance does not appear to be a certified GM dealership and for that, we are unable to back the worksmanship done at independent facilities since those locations since are not affiliated with General Motors. We are only able to discuss potential cost assistance with certified GM dealers. If you would like to have an official diagnosis done at a GM dealer, we may be able to explore cost assistance afterward. I look forward to your reply.

William R.

Chevrolet Customer Care

American Heritage Performance accepts GMPP, so not sure why they are not authorized, because they are not a car dealership? The heads are off both cars, so taking them to a dealership is not an option.

They have been diagnosed and the specs were posted in the "Out of spec Registry" for my car yesterday . My issue is even new heads have been found to be improperly machined, look at Hib Halverson'so 2012 Z06 write up. The only true fix is to have the heads properly machined by a competent shop. I do not trust most dealerships and their mechanics. I may just pursue legal action at this point. There is enough evidence on this forum to back up a legal claim if that is how you guys want to play the game. What are the odds of taking two different year model Z06's into a shop the same day and both out of spec to the point of imminent engine failure?

Dan,

Thanks for your response. Per GM Policy, we are only able to review potential cost assistance with certified GM dealers. If you'd like to have the vehicle put together in order to seek a dealer's assistance, I'd be more than happy to aid in that process. However, please know that I would no longer be in the position to assist if you retain an attorney. If this is the case, you will be in contact with the right parties once your representative(s) contact GM.

William R.

Chevrolet Customer Care

Link to comment
Share on other sites

I have not replied yet, but I will not take my car to a GM Dealer to have them diagnose or fix it. I would rather be out of pocket than have them touch my car.

Link to comment
Share on other sites

Unfortunately when you talk of a suit or lawyers, most companies will cease conversation. The one positive for taking your car to a dealership would be a nationwide warranty for X amount of years/miles.

Link to comment
Share on other sites

At this point I could care less,I trust my shop more than anything GM would do. They know it's an issue, what needs to happen is a class action suit on behalf of all Z06 owners that have blown motors or have out of spec guides.

Link to comment
Share on other sites

GM doesn't care. As long as the car makes it through their warranty, they are covered. The way they handled this whole situation, as you are seeing, is one of the main reasons I will not buy another GM car/truck. The customer service monkey is nothing more than someone to send out canned lawyer approved responses. They are not going to do anything for you.

Sad thing is, if you took it to a dealer, and they didn't land up making it worse or messing the car up, they would just put on another set of heads that would do the same thing in 10-30k miles, so taking it elsewhere is the best option. Get it fixed and move on and just remember what you had to pay for when it comes time to buy a new car.

Link to comment
Share on other sites

Create an account or sign in to comment

You need to be a member in order to leave a comment

Create an account

Sign up for a new account in our community. It's easy!

Register a new account

Sign in

Already have an account? Sign in here.

Sign In Now
×
×
  • Create New...