Head work
12-09-2017, 09:14 PM
#2
Melting Slicks
Member Since: Jun 2005
Location: Rochester NY
Posts: 2,734
Received 1,678 Likes
on
878 Posts
2018 C6 of Year Finalist
St. Jude Donor '10, '17
You don't need new heads.
If you can do the work yourself, then first conduct a wiggle test to get an idea of what shape the guides and valves are in.
If the heads need work and you can do the work yourself, pull the heads off yourself (free) then send to American Heritage Performance. For around $1500 they will replace the guides, polish the intake valves, replace the exhaust valves and clean up the heads. Put fixed heads back on car - done.
If you can't do the work yourself, then plan on around $800 - $1000 labor to remove and re-install the heads at a reputable shop, bringing grand total to around $2500 ($1000 labor + $1500 head repair). In this scenario you buy the heads first from AHP ($1000 core deposit), then you pay the shop to remove the heads, install the heads that were sent to you and then mail AHP your original heads and you receive back the $1000 core deposit. This way your car isn't down for long.
If you can do the work yourself, then first conduct a wiggle test to get an idea of what shape the guides and valves are in.
If the heads need work and you can do the work yourself, pull the heads off yourself (free) then send to American Heritage Performance. For around $1500 they will replace the guides, polish the intake valves, replace the exhaust valves and clean up the heads. Put fixed heads back on car - done.
If you can't do the work yourself, then plan on around $800 - $1000 labor to remove and re-install the heads at a reputable shop, bringing grand total to around $2500 ($1000 labor + $1500 head repair). In this scenario you buy the heads first from AHP ($1000 core deposit), then you pay the shop to remove the heads, install the heads that were sent to you and then mail AHP your original heads and you receive back the $1000 core deposit. This way your car isn't down for long.
The following users liked this post:
American Heritage (12-12-2017)
12-09-2017, 10:56 PM
#3
Race Director
Be advised that the vast majority of LS7 engines will go for many, many miles on stock heads. Read up on the subject, and then if you decide to do it, you will also find lots of information about how to get it done.
There are no simple answers because no one knows the failure rate. I think it is less than 1 per cent.
There are no simple answers because no one knows the failure rate. I think it is less than 1 per cent.
12-10-2017, 01:05 AM
#4
You need ti adress the heads the heads will eventually fail its your decision.....look up my builds, I'm on my second set of heads this time bronze guides...but what do I know people on here haven't spent the money to experiment what actually causes this failure I will pull these heads at 20k....them if they are worn i will do the moldstars....
12-10-2017, 08:09 AM
#6
Melting Slicks
Simplest easiest way. Just remove all all your rockers. Take your hand and firmly try to move the valve via the spring. Make a small sharpie line on the valve tip so you can see if the valve is really moving. (Wipe off oil of course before doing any of this.) If you see or feel any slight movement ( the guide is toast) and you have to be very firm when wiggling. I had 12 out of 16 way out of spec at 12,800 miles. Got a report of the clearances from AI when I had my heads rebuilt and CNC'd. Good luck. 
You tube video should be still available.
You tube video should be still available.
12-11-2017, 03:45 AM
#7
Le Mans Master
Be advised that the vast majority of LS7 engines will go for many, many miles on stock heads. Read up on the subject, and then if you decide to do it, you will also find lots of information about how to get it done.
There are no simple answers because no one knows the failure rate. I think it is less than 1 per cent.
There are no simple answers because no one knows the failure rate. I think it is less than 1 per cent.
The following users liked this post:
REDZED2 (12-11-2017)
The following users liked this post:
REDZED2 (12-11-2017)
12-11-2017, 11:25 AM
#9
Le Mans Master
Be advised that the vast majority of LS7 engines will go for many, many miles on stock heads. Read up on the subject, and then if you decide to do it, you will also find lots of information about how to get it done.
There are no simple answers because no one knows the failure rate. I think it is less than 1 per cent.
There are no simple answers because no one knows the failure rate. I think it is less than 1 per cent.
The way your posts come across, you sound like part of the "valve guide denier" crowd. Just as we all now know the Earth is indeed round, in the same way we know bad valve guides can and will cause valve failures; we have all the data we need to make that determination at this point.
Please keep your Kenny Rogers school of engine building (The Gambler) advice off of these forums. You aren't helping anyone.
Last edited by Dan_the_C5_Man; 12-12-2017 at 12:48 AM.
12-11-2017, 07:25 PM
#10
This is where I got mine done. https://www.latemodelengines.com/
20K plus miles now. Running great.
20K plus miles now. Running great.
Thanks!
12-11-2017, 07:30 PM
#11
Team Owner
Last edited by MTPZ06; 12-11-2017 at 07:31 PM.
12-11-2017, 11:58 PM
#12
Drifting
We have done 3 LS7 engines because the stock LS7 dropped valves and many customer requests to replace the guides and valves on them. 2 were road raced one was not. I think doing bronze guides/valves is cheap insurance on a $14k+ engine plus install maybe $17k.
Last edited by tekhombre; 12-12-2017 at 12:35 AM.
12-12-2017, 04:05 AM
#14
Supporting Vendor
Member Since: Sep 2013
Location: Harbor City California
Posts: 2,815
Received 1,012 Likes
on
533 Posts
Our basic package 4 using one of our core sets (no down time) is $2,358 (plus shipping to you). Send back your old heads (fully assembled) and we will credit you back your $1,000 core deposit.
Our "package 4 heads" are the way GM should have produced their LS7 heads.
Feel free to give us a call
310-326-2399 or Email HP@americanheritageperformance.com
If you have any questions or would like to place an order.
http://www.americanheritageperformance.com/
12-12-2017, 08:48 AM
#15
Race Director
Member Since: Mar 2006
Location: Everywhere and Nowhere at all
Posts: 15,357
Received 1,679 Likes
on
1,135 Posts
I purchased my 08Z w 22K back in Feb 17.... First stop was Kohle @ AHP... Now @ 26K miles, (H/C/I/E) I have ZERO worries in dropping a valve. Don't be "that guy" who does a follow up post saying your 23K mile LS7 dropped a valve. You read about it almost weekly.
1%???? come on man.... Its way more than that.
1%???? come on man.... Its way more than that.
12-12-2017, 09:53 AM
#16
Safety Car
What part of Texas are you in? There are plenty of shops in Texas competent to do the R&I of the heads, and many of them will work with WCCH or AHP to have the machine work done.
12-12-2017, 10:19 AM
#17
Drifting
12-12-2017, 10:37 AM
#18
Racer
The guides all wear, just at different rates basically. Some may gave the guides checked at 10k miles and be way out of spec, some make it much longer. To me, it was a no brainer to spend a couple thousand and go with a proven fix for a problem that absolutely does exist. Had mine done by RPM motorsports and am very happy that I did.
The fix, whether you do it yourself or have someone else do it, is having the heads re machined, then replacing the guides with bronze valve guides, using either SS exhaust valves or the other ones the are proven like the ones AHP typically uses, then a dual valve spring to handle the extra weight of the new valves.
The fix, whether you do it yourself or have someone else do it, is having the heads re machined, then replacing the guides with bronze valve guides, using either SS exhaust valves or the other ones the are proven like the ones AHP typically uses, then a dual valve spring to handle the extra weight of the new valves.
12-12-2017, 11:21 AM
#19
Race Director
We would all respect your "professional statistician" opinion on this subject much more if you would add "..But at least have the valve guides checked to see if they are out of spec..".
The way your posts come across, you sound like part of the "valve guide denier" crowd. Just as we all now know the Earth is indeed round, in the same way we know bad valve guides can and will cause valve failures; we have all the data we need to make that determination at this point.
Please keep your Kenny Rogers school of engine building (The Gambler) advice off of these forums. You aren't helping anyone.
The way your posts come across, you sound like part of the "valve guide denier" crowd. Just as we all now know the Earth is indeed round, in the same way we know bad valve guides can and will cause valve failures; we have all the data we need to make that determination at this point.
Please keep your Kenny Rogers school of engine building (The Gambler) advice off of these forums. You aren't helping anyone.
However, I feel that your assertion that "...we know bad valve guides can and will cause valve failures;" is absolutely incorrect. It appears that many LS7 engines have run to high mileage levels with "bad" valve guides. It appears to be a robust design.
I'm just talking about the facts here. Not that I think it is great to run an engine out of spec. But the engine does, in fact, tolerate it in many cases.
12-12-2017, 11:24 AM
#20
Race Director
Let me ask it this way. How many failures are you aware of? Round it to the nearest hundred.
Just in the Z06 and 427 Convertible, over 30,000 engines were produced. Most of them in the first four years. So unless you think the engine failures are over 300 (I do not), then the failure rate is less than 1%.
And we know the LS7 has been used in other applications also.
Last edited by Tonylmiller; 12-12-2017 at 11:43 AM.