I agree

We have a worked head that seemingly has worn guides. Obstensibly this head had the valve seats worked, run out, and concetricity checked at WCCH, but maybe it turns out they weren't?

If run out and concentricity do check out, then how about the other things you suggest?

It would also seem we have an opportunity to narrow down some of the basic causes of guide wear, because I would think that a worked head should have fundamentally addressed some of the seven basic causes of guide wear you outlined in your other thread.

 

my stock setup was on till 83K whats your point? heads are being reworked now....#4 was on borrowed time....have seen cars with 14K total destruction...if you are under warranty then drive on

 

My WCH passed the wiggle test with 20K and a year of track duty. Tested by a GM master tech (corvette specialist) with wiggle testing experience. Same tech measured 2 of my buddies stock heads with same milage and track duty. Both those heads were out of spec and heads were reworked.


DH

 

Good to hear, always need both sides of the story.

 

From what I understand a customer recently shipped these heads to AH, so these are not the same as previously mentioned. The wiggle test was done as a rough measurement, I am sure AH will chime in with a more detailed analysis of the heads.

 

They're not on this forum, they don't know. Anyway there are way more unknowns that knowns in this situation.

And the OP is stirring the pot - it's not his car. Until all the questions surrounding these videos are answered, it is nothing more than a single data point with many unknown variables put out by a competing shop. I have no reason to believe that AH is not telling the truth but it doesn't seem like anyone including them know the full story on these heads.

And until heads from all the shops are being wiggle tested after X, Y and Z miles then you can't compare one to another. Where are post-machining wiggle or bore tests on heads from AH, Lingenfelter, etc? I haven't seen them. Not many seem to bother checking them after the fact and there are certainly a lot out there. I'll be checking mine after about 20k miles but I only have 4k on them so far.

And Michael_D brings up a good point that I was also going to mention - if the heads are off and on a bench why the wiggle test? That is a marginally accurate test reserved for heads that are still installed on an engine or for those that don't have access to tools like a bore gauge. A shop such as AH should be using nothing but a bore gauge to measure heads on a bench.

 

The OP is a AH Customer that currently has his Z at AH getting work done, from what I understand he visits the shop often (while waiting for his final parts to arrive for his build) and AH showed him these heads that just came in from a customer who shipped them to his shop. Let's give AH a chance to chime in before casting stones.

 

Nothing in the combination is consistent with what Katech recommends except the type of guide used.

This situation indicates an intake guide failed (out of spec). Did this head use the proper coated ti/mo intake valve that katech recommended after saying they weren't happy with the long-term wear of the tumble polished valves with the bronze guides?

Lots of missing details, but I think we can all make an assumption on this. Some of us that followed Katech's WCCH head recipe (OEM valves, katech ti/mo coated intakes with PSI springs/ ti retainers and bronze guides) while others followed the WCCH SS, tumble polished intakes, dual spring recipe.

I seriously doubt the guide wear of the tumble polished valves will be exactly the same as the ti/mo coated valves. It could go either way, but its unlikely they both go the same way at the same rate.

 

WCCH has NEVER posted anything on this board so what the hell are you talking about?

Plus the OP is a big anti-WCCH/pro AH supporter so I'm taking this with a grain of salt. It isn't his car. I still find it strange that AH is the only shop/place finding all these out of spec WCCH guides, yet no other shop or customer has had an issue. When we start seeing some reports from anyone besides the competition.

 

Heads up guys, these videos were posted by American Heritage. They're sure to pop in for an explanation. I truly hope they can shed some light on the details, I think they're doing great work specifically tailored for the LS7 that most shops around here have left behind.

 

Its just a wiggle test, showing wear. Regardless of shop or person posting, its useable information to help "guide" our own decisions. See what I did there?

There seems to always be a few on this forum hell bent on conspiracy against another shop. There isn't. My integrity is beyond most people you will ever meet, ask Jim over at Halltech.

As for AHP, I believe in the owner as I have had personal experiences where he literally could have taken my money and I would have been none the wiser, but he didnt. He was 100% truthful and told me what had been done, what needed to be done. If you would like more info on those situations I'd be glad to discuss it in a PM. Enjoy the rest of your day

 

The heads were sent into us by a customer for repair and reworking.
What we know about the heads is what the customer has told us about the heads and from obvious observation.
The heads were wiggle tested at the customers request. The video's were made for the customer. We often take pics and videos to send to customers. Most the time We text or email but sometimes we post them on youtube for ease of uploading/ect...
We will post up the bore/mic measurement clearances for the guides in question sometime later this evening.

Customer has had the vehicle around 10,000 miles (before pulling the heads). When he purchased the vehicle it was known that the heads were redone 5k miles before the purchase/sale of said vehicle. Customer said it had a very mild cam. We asked for additional information regarding the camshaft specs/ect... Customer was unable to provide them, he just told us it was "mild". He has only driven the car on the street with no track days. He was told by the previous owner that the vehicle was a street only car but we all know how that goes(5k unknown, 10k street).

 

Ruh Roh.

 

Mr. Know-It-All, yet you think everyone should follow your advice on everything Z06 related and are the first person to always bash AH, yet you have never used their shop, used their re-worked heads, but you bash them based off of what? I thought we hashed a lot of this out on the ACE Forum, where you seemed to change your tune a bit.

 

That wear is also indicated to be on the exhaust side as well, makes the tumble polish vs TiMo coated intake valve position moot.

Your first sentence above, indicating the use of bronze exhaust guides in WCCH heads intended for both Katech and others, is what's important.

Unless your position is that Katech has figured out a way to make bronze guides somehow work better on the exhaust side, than has anyone else.

 

All I said was take it for what it is worth. I didn't bash them, just find it strange that they are the only place that finds out of spec WCCH heads. Several other members/vendors have tested at 15-40k+ miles with no wear. Where did I bash AH? Why aren't other shops finding this?

I've never used AH heads, hell I've never used WCCH heads either on my personal car, just 4-5 friends cars that all have great results. Then again they are all building fast cars, not stock rebuilds.

If I was sending my heads out, WCCH wouldn't even be in the top 5 picks of places I would send them to so please don't call me a WCCH fan boy. I just find threads like this silly at best. Just like the previous thread of a single PRC head having out of guide specs, people want to say they are all bad or PRC does bad heads when there are tons out there without issue.

 

How can a shop choose what a customer brings in or ships them to get re-worked? You said you are going to take this with a grain of salt, to me you are stating "Why is it only AH finding this issue" as they are the competition? That is a bash in my book implying they are playing dirty in the head business.

Maybe more people should get their heads re-checked whether it is WCCH, AH, AI, Texas Speed, etc. Let's see if everyone is doing a good job long term with their version of the "Fix". I know AH has one customer car with over 50,000 miles on a set of re-worked heads, they were checked and all in-spec. I plan on re-checking mine once I rack up 20,000 miles on my heads, I have only driven 700 miles since mine were recently done.

 

Maybe everyone should get their guides checked an impartial source. Thats what I did ...............


DH

 

...and so was every single LS7 that blew due to failed exhaust valves, due to worn guides.. Proves nothing, unless you take the time to check them.

 

Are you willing or able to post up any run out measurements, concentricity, or any other misalignment?