Katech LS7 Head Fix Group Buy

[j o n]

Originally Posted by Katech_Zach

I misinterpreted this the first time you asked, my apologies.

Our typical car shop time from start to finish is 4 to 6 weeks. This can be sped up if scheduling is done properly, but typically jobs are interwoven into a shop that is already at capacity.

If you need the car sooner, this most likely can be arranged as long as we have all of the parts pulled and ready to go, dyno time scheduled, and a tech ready to go.

Thanks for the response. Appreciated.

So for example: it's 4-6 weeks to just repair the heads only? That with a core exchange (fixed heads ready to go on the shelf) or do you take my heads off the car, machine the heads, and then return the same heads to my car? Just want to confirm what is going on for the 4-6 weeks my car would be sitting there. Inside/outside storage? Engine open without the heads on it?

Could you elaborate on the time needed for for each of these options?
Stage 2 Head/Cam (Includes the Head Fix): $8,055.00
Head Fix Only: $4,194.47
Head Fix + CNC Ports: $4,597.50
Head Fix + CNC Ports + Chambers: $4706.4

Not to be nit-picky... but most of us would have to travel good distances to and from katech to drop off and pick up the cars and having the cars just sitting there unnecessarily is also of concern.

[Katech_Zach]

Originally Posted by j o n

Thanks for the response. Appreciated.

So for example: it's 4-6 weeks to just repair the heads only? That with a core exchange (fixed heads ready to go on the shelf) or do you take my heads off the car, machine the heads, and then return the same heads to my car? Just want to confirm what is going on for the 4-6 weeks my car would be sitting there. Inside/outside storage? Engine open without the heads on it?

Could you elaborate on the time needed for for each of these options?
Stage 2 Head/Cam (Includes the Head Fix): $8,055.00
Head Fix Only: $4,194.47
Head Fix + CNC Ports: $4,597.50
Head Fix + CNC Ports + Chambers: $4706.4

Not to be nit-picky... but most of us would have to travel good distances to and from katech to drop off and pick up the cars and having the cars just sitting there unnecessarily is also of concern.

4-6 weeks is for an entire car shop job (The stage 2 package for reference). The cylinder head fix is typically a maximum of a 2 week turn around from start to finish, this is if you send the heads in. If you were to send a car in, it would look more like 3 weeks when you factor in the pre/post vehicle inspections, disassembly, and reassembly.

There is no core exchange, we re-machine your existing cylinder heads.

The car will always be stored inside, we would not be overfilling the shop to the point where we had to store cars outside. This is why we would have scheduling slots for a group buy like this.

We seal off all of the ports/fittings/hoses that are exposed when the heads are removed. You will not have to worry about debris getting into the engine.

~4-6 Weeks Max Stage 2 Head/Cam (Includes the Head Fix): $8,055.00
~3-4 Weeks Max Head Fix Only: $4,194.47
~3-4 Weeks Max Head Fix + CNC Ports: $4,597.50
~3-4 Weeks Max Head Fix + CNC Ports + Chambers: $4706.4

Again, if everything was scheduled accordingly and we have all of the parts prepared prior to arrival, this time can be decreased. If there are hard deadlines that you need to hit and you have to have your car by, we can discuss that as well.

[Mark_Z28]

Originally Posted by Katech_Zach

Yes, you are correct. Mileage of the vehicle is technically irrelevant unless there is wear associated with this mileage. I used mileage as a reference because this seems to be the the general average from all of the LS7-equipped vehicles that we have had. Some cars are out of spec within a few thousand miles because they are heavily abused, other cars last a life time because they spend their lives under 3000 RPM on the highway.

We consider anything that is over the .002 mark to be out of spec, GM considers around .003 to be the upper bound. Anything that has an "hourglass" shape to the measurement (.0025 top, .002 middle, .003 bottom for example) needs to be addressed because this will cause the valve to wobble. This is where the wiggle test comes into play, the average user can identify if they are horribly out of spec.

We use the solution that has been proven throughout our motorsports history to permanently solve these issues.

Thank you I appreciate that.

[Jberg805]

What would the price for head fix and stage 2 package be without the installation?

[The_Raging_Bull]

An old member who visits occasionally.I read every thread on this issue that matters. Too many answers on the corvette forum we’re just so much throw away replies. On the Z06 personally I think there are issues...I’ve got one and need to do my heads. On my Z/28 I’ll slog along, having a 7 year 70000 mile warranty, so before I do anything mechanical, I’ll enforce my warranty.

However an article by Hib Halverson over on the corvette action center called “The Ruthless Pursuit of Power, The Mystique of the 7 Liter 7000 rpm LS7” details the changes in the later LS7s in our Z/28s as well as later produced crate engines. These were changes in super polished valves and improved valve guise install and 100%inspection. Check out the article, pages 18 to 22. I’ve posted the several times every time these issues are raised. The reason I paid $1500 for a premium warranty...to avoid any valve issues.

Personally I love the LS7, and there are only about 200 dropped valves out of 10807 engines (or so). That’s roughly 9000 zZ06s and 1807 Z/28s.

https://www.corvetteactioncenter.com...te-ls7-engine/

[Katech_Zach]

Originally Posted by Jberg805

What would the price for head fix and stage 2 package be without the installation?

I shot you a PM.

Originally Posted by The_Raging_Bull

An old member who visits occasionally.I read every thread on this issue that matters. Too many answers on the corvette forum we’re just so much throw away replies. On the Z06 personally I think there are issues...I’ve got one and need to do my heads. On my Z/28 I’ll slog along, having a 7 year 70000 mile warranty, so before I do anything mechanical, I’ll enforce my warranty.

However an article by Hib Halverson over on the corvette action center called “The Ruthless Pursuit of Power, The Mystique of the 7 Liter 7000 rpm LS7” details the changes in the later LS7s in our Z/28s as well as later produced crate engines. These were changes in super polished valves and improved valve guise install and 100%inspection. Check out the article, pages 18 to 22. I’ve posted the several times every time these issues are raised. The reason I paid $1500 for a premium warranty...to avoid any valve issues.

Personally I love the LS7, and there are only about 200 dropped valves out of 10807 engines (or so). That’s roughly 9000 zZ06s and 1807 Z/28s.

https://www.corvetteactioncenter.com...te-ls7-engine/

The premium warranty is a great thing to have, I would have bought it if I purchased one of these vehicles new. Hib is an extremely respected member of the corvette community, he is very knowledgeable and passionate about everything and anything LS related.

GM did improve their LS7 head production quality in the later model years, but we have found that they still seem to wear out (even if it is at a decreased rate). There is no 100% issue to point a finger at throughout the whole process, but the majority of the parties involved suspect that there was a supplier quality issue. The issue was in the machining process for the cylinder heads that involved the valve guide bores. You can set clearances to be 100% correct from stem-to-guide, but this does not always mean the valve is 100% concentric to the valve seat.

[The_Raging_Bull]

Originally Posted by Jberg805

What would the price for head fix and stage 2 package be without the installation?

Search on the Katech website is your friend

[Katech_Zach]

Originally Posted by The_Raging_Bull

Search on the Katech website is your friend

I do not believe pricing without install is on the website.

[hjdca]

Originally Posted by Katech_Zach

Yes, you are correct. Mileage of the vehicle is technically irrelevant unless there is wear associated with this mileage. I used mileage as a reference because this seems to be the general average from all of the LS7-equipped vehicles that we have had. Some cars are out of spec within a few thousand miles because they are heavily abused, other cars last a life time because they spend their lives under 3000 RPM on the highway.

We consider anything that is over the .002 mark to be out of spec, GM considers around .003 to be the upper bound. Anything that has an "hourglass" shape to the measurement (.0025 top, .002 middle, .003 bottom for example) needs to be addressed because this will cause the valve to wobble. This is where the wiggle test comes into play, the average user can identify if they are horribly out of spec.

We use the solution that has been proven throughout our motorsports history to permanently solve these issues.

Hello Zach, thanks for all your help. It seems that high rpm running accelerates the valve guide wear ? So, tracked Z/28s should have more "out of spec" valve guide wear vs. street driven Z/28s ? Have you guys seen evidence of this ? Thanks in advance for any info.

[HoodCheck]

Do you guys have just straight purchase without providing cores? I'd be curious of the price if so, with or without the discount.
From what I understand, the bronze valve guides arent as good as the PM guides in terms of longevity (my Z/28 is a street only car, barely raced, and want to get as many miles as possible before rebuilding a thing). That being said, if the answer to the above question about the sale without a core is "yes", is it possible to get PM guides?

[HoodCheck]

Originally Posted by The_Raging_Bull

An old member who visits occasionally.I read every thread on this issue that matters. Too many answers on the corvette forum we’re just so much throw away replies. On the Z06 personally I think there are issues...I’ve got one and need to do my heads. On my Z/28 I’ll slog along, having a 7 year 70000 mile warranty, so before I do anything mechanical, I’ll enforce my warranty.

However an article by Hib Halverson over on the corvette action center called “The Ruthless Pursuit of Power, The Mystique of the 7 Liter 7000 rpm LS7” details the changes in the later LS7s in our Z/28s as well as later produced crate engines. These were changes in super polished valves and improved valve guise install and 100%inspection. Check out the article, pages 18 to 22. I’ve posted the several times every time these issues are raised. The reason I paid $1500 for a premium warranty...to avoid any valve issues.

Personally I love the LS7, and there are only about 200 dropped valves out of 10807 engines (or so). That’s roughly 9000 zZ06s and 1807 Z/28s.

https://www.corvetteactioncenter.com...te-ls7-engine/

For me the link you sent didn't work, so just providing another, starting at the page you referenced
https://www.corvetteactioncenter.com...-engine18.html

[Katech_Zach]

Originally Posted by hjdca

Hello Zach, thanks for all your help. It seems that high rpm running accelerates the valve guide wear ? So, tracked Z/28s should have more "out of spec" valve guide wear vs. street driven Z/28s ? Have you guys seen evidence of this ? Thanks in advance for any info.

It is hard to say that we have "hard evidence" of this in the form of data, because customers typically do not document when they track their car, how long they track it, how hard they beat on the car, etc. The only real evidence is the mileage on the vehicle. We have a ton of data on the 06-13 Z06 corvettes, and we can easily conclude that track cars with low mileage exhibit the same wear as street cars that have high mileage. There is 100% a correlation between engine load and valve guide wear. The longer you are in the higher RPM ranges, the longer your valve guides are exposed to higher loading forces.

Originally Posted by BWilsonSr

Do you guys have just straight purchase without providing cores? I'd be curious of the price if so, with or without the discount.
From what I understand, the bronze valve guides arent as good as the PM guides in terms of longevity (my Z/28 is a street only car, barely raced, and want to get as many miles as possible before rebuilding a thing). That being said, if the answer to the above question about the sale without a core is "yes", is it possible to get PM guides?

We do have the ability to do a straight purchase. This would be up to the customer.

As far as the bronze versus powdered metal guides go, in theory the PM would be more durable than the bronze (with the proper valve material), but we do not have any extended test data on this. What we do know is our bronze guides paired with our ti/mo valves holds up to tons of abuse, and it will last for the life of the engine. We did the research years ago with other types of material for both the guide and the valve, this resulted in our bronze + ti/mo combination. In the original post, there is data showing a customer that came in for a 20k mile + 10 HPDE guide check-up. This shows that our solution will last.

To answer your questions:
-Yes, we can bare cylinder heads and fix the guides with no core
-No, we will not use PM guides with our Ti/Mo valves. This combination may work, but we do not have validation data on this and would not be able to stand behind a product with no data.

[HoodCheck]

Originally Posted by Katech_Zach

It is hard to say that we have "hard evidence" of this in the form of data, because customers typically do not document when they track their car, how long they track it, how hard they beat on the car, etc. The only real evidence is the mileage on the vehicle. We have a ton of data on the 06-13 Z06 corvettes, and we can easily conclude that track cars with low mileage exhibit the same wear as street cars that have high mileage. There is 100% a correlation between engine load and valve guide wear. The longer you are in the higher RPM ranges, the longer your valve guides are exposed to higher loading forces.



We do have the ability to do a straight purchase. This would be up to the customer.

As far as the bronze versus powdered metal guides go, in theory the PM would be more durable than the bronze (with the proper valve material), but we do not have any extended test data on this. What we do know is our bronze guides paired with our ti/mo valves holds up to tons of abuse, and it will last for the life of the engine. We did the research years ago with other types of material for both the guide and the valve, this resulted in our bronze + ti/mo combination. In the original post, there is data showing a customer that came in for a 20k mile + 10 HPDE guide check-up. This shows that our solution will last.

To answer your questions:
-Yes, we can bare cylinder heads and fix the guides with no core
-No, we will not use PM guides with our Ti/Mo valves. This combination may work, but we do not have validation data on this and would not be able to stand behind a product with no data.

Whats the price without cores? I just want something to bolt on and go basically; might be interested in the additional porting and such too if it gets a tad more power. Feel free to PM it if you don't want to publicly announce that cost

[Katech_Zach]

Originally Posted by BWilsonSr

Whats the price without cores? I just want something to bolt on and go basically; might be interested in the additional porting and such too if it gets a tad more power. Feel free to PM it if you don't want to publicly announce that cost

PM'ed. Are you planning on tuning the vehicle after putting the new heads on, or are you leaving it stock?