OhhhApieceOfCandy

Obviously the stock heads are problematic when untouched and there are numerous reports of "fixed" stock castings dropping valves but are has anyone had a failure/dropped a valve with aftermarket castings?

grinder11

Any aftermarket head could experience a dropped valve. Maybe from too much red showing on the wrong side of the tach needle. Or from a defective valve. Or using the wrong, or an inferior, valve spring. Any head could drop a valve, for many reasons. However, the key is how frequently this happens. You'll find few complaints online when using Brodix, AFR, Mast, PRC, Trick Flow, etc. Valve strength is another key. But there are hundreds of posts on the LS7 heads dropping valves. The early LS7 heads used an exhaust valve with stems that were just too thin. The intakes had a CRN coating that was, arguably, too thin or applied on valve stems that weren't finished as smoothly as they should've been. Then there were questionable machining practices/non concentric valve seats to guide centerlines. The LS7 heads are the most perfect example of Murphy's Law I have ever seen.

OhhhApieceOfCandy

This is more of a factor of sample size than anything else. There are probably 10x more ls7 casting heads out there than there are aftermarket castings so saying you rarely hear about it isn't saying much. The point of the question is to see if people are experiencing failures in the same way that stock castings fail.

grinder11

OK. Plenty of fixed heads still have issues. Aftermarket heads are more plentiful than you may think, or the 6 or 7 companies producing them would be defunct. Also, they are probably subjected to more abuse than the LS7 heads. If you want to fix your heads, which may, or may not, have problems, go for it. But realize they may be, or may not be, "fixed" for the long haul.
@Dj_or_dj

Z.06

I have asked before for data on aftermarket heads to prove or not that the aftermarket head design either fixes the LS7 head problems or not for the long haul. Many months later I am still waiting for data to prove this issue one way or another. Let's put a 20,000 mile minimum on credible experience and see what data we get to prove an important point. Let's have it or at least admit that you really don't know yet.

grinder11

I'll only ask this; has anyone here ever heard of any other cylinder head having so many reported issues as the LS7 heads have? Don't kid yourselves that there aren't 10s of thousands of aftermarket heads out there. Sure, not all are for the LS7 heads. Most are on hot rodded engines, not low mileage collector cars. Aftermarket heads aren't as bean counter limited, either. I've been around a lot of dragstrips in the last 50+ years. Bad reputations and durability issues travel fast by word of mouth. I've never heard anyone complaining about their aftermarket heads. Ever. Only complaints I've ever heard were OEM LS7 owners. There is a recent thread on this forum started by a GM engineer who was seeing all these problems manifest themselves. He tried to stop production so they could fix the issues. He nearly lost his job! Hib Halverson has verified the engineer is legit. See "A sad tale of greed" in this very section.......
BTW-I love my LS7, too. But there's no excuse for what has happened to many of our fellow LS7 owners, including me. Nobody likes laying out $15,000-$20,000 for another engine. Many simply can't afford another engine without raiding their retirement accounts, or being threatened with a divorce!!

Z.06

OK, so let's not get the data on aftermarket heads. Let's believe what we want to believe with no data to support a conclusion.

grinder11

I'm totally for anyone posting actual, accurate data. But that doesnt exist for even the OEM LS7 heads. If 50 years experience with drag racing, not just what I believe, doesn't count for anything, so be it. But nobody else I've seen, or know about here, has any actual hard numbers. So that leaves nothing but personal experience. I'm listening, and watching. But actual data doesn't exist, or wont be made public. So what else can you go by but actual, personal experience, which isn't a "belief?"

Dj_or_dj

My Mamo MMS heads are still intact … 13,500 miles… not a whisper or creek.

dmuellenberg

So go for it - you do the research and let us know. You do understand that it is pretty difficult to gather that information given all the different kinds of aftermarket heads? What do you do, get a list of everyone who has installed aftermarket heads and call them to see if they've had an issue?

Z.06

Well I have been out there two or three times asking for this data, with no responses, so I do understand that it is pretty difficult to gather this data. Different types of aftermarket heads has nothing to do with the difficulty. One either has a positive or a negative experience, or they have not satisfied my proposed mileage criteria., which I put out there to eliminate garage queens - which do not prove anything either way.. I will not be calling the users of aftermarket heads to see if they meet the criteria. My expectation is that all users with qualified experience will offer it to help fellow CF members.

So what reasons may exist that after repeated attempts, no CF members have responded saying that they have 20k miles on their aftermarket heads and there have either been no heads/valve problems ? Perhaps these could be the reasons:

1. No one on CF has managed to put over 20k miles on their LS7 after installing any aftermarket casting heads. This seems unlikely, but it is a real possibility. If this is the case, one could say that aftermarket casting heads do not have much of a proven record, do they?
2. Owners with aftermarket heads on their LS7 have switched to aftermarket heads, but have not accumulated enough miles to prove that the aftermarket heads are superior to corrected OEM heads.
3. Owners with aftermarket heads and less than 20k miles have already experienced failures such as excessive valve guide clearance or failure in less than 20k miles, but the aftermarket head manufacturer is taking care of the problem in order to keep the discussion of same out of CF discussion.

Still awaiting data.....

Burntoutaccountant

I’ll let you know in a year. I have Brodix br7 heads going on my car. It’s my dd.

grinder11

I will add that the bronze guides in the AFR 225 heads I once had on a Darton 427 had guides worn out at 30,000 miles, worn far worse than my LS7 OEM PM guides were. Bronze guides will not last as long as hardened PM guides. Probably one reason GM has been using hardened PM guides for quite awhile. My AFRs also had very good, very strong Ferrea valves in them. Never knew they were badly worn until I installed new valve springs, at which time I had to pull the heads, and sent them to AFR to be refurbished. The OEM LS7 exhaust valves are not as strong as the Ferrea valves, early style, or later style. The CrN coated Ti intakes will destroy any guide when the coating has worn off, which 7 of my 8 had done. Aftermarket or OEM with hardened guides are going to wear less than bronze guides, OEM or aftermarket. When I sent my LS7 heads to AHP, I had them install their hardened PM guides, which are supposed to be harder than the GM guides. I didn't go for the MS-90 guides. I havent seen any trouble 30,000 miles later. FWIW......

dmuellenberg

What do you mean, no CF members have responded? There was one who posted on this thread earlier. And not everyone who owns a C6 Z06 is a CF member. Another reason is that most people only comment when they have an issue, so the lack of complaints with aftermarket heads is a good thing. And if you are awaiting more positive data, you can add my data to your list as someone who has over 60k on my aftermarket heads with no failures.

Not to mention that the title of this thread is asking for confirmed reports of failures, not non failures.

Z.06

dmullenberg has some good points and I appreciate them. Any collection of data should collect both the experience with no failures and with failures. So now I have dmullenberg with over 60k miles on aftermarket heads with no failures. Dmullenberg, please specify the manufacturer of your aftermarket casting heads as this is impressive performance. I noted that grinder11 also has good experience on his heads, but these seem to be corrected heads based on OEM castings. Am I wrong? So the current score on aftermarket heads seems to be one set of heads of unknown aftermarket origin with a 60k miles life without failure. I will need dmuellenberg to validate the supplier of these heads to step forward and verify this datapoint. This seems like a success for sure.

Grinder11 has noted his set of AFR225 heads, which surpassed 30k miles before failure of the bronze valve guides. According to my criteria, this must be scored as a success, though some would say otherwise.

As dmuellenberg notes, both good service and failures should be tracked to be fair. I am not interested in tracking aftermarket heads with less than 20k miles service life, as I do not regard that experience as valid for the intended premise.

So far it looks like the data shows 2 successes and no failures, and I am hoping for a much wider data response so we can prove whether aftermarket heads are more reliable than OEM casting heads.

dmuellenberg

I see I misspoke when I said I had 60k on my aftermarket heads. They aren't aftermarket, they are stock heads with updates - sorry for the confusion.

grinder11

Z.06 is correct on both my AHP fixed OEM LS7 heads, and my worn out aftermarket AFR 225 bronze guides. Actually, I was extremely disappointed that the AFR heads wore out in just 30,000 miles. I had .598"/.603" lift Cam Motion by Alan futral in this engine. Duration was 232°/236°, on a 112° LSA. This was hardly an all out effort cam! I wouldn't consider them successful, especially since those 30,000 miles were accrued in only about 13 months!! Yes, I piled on a lot of cruising miles. Went on a round trip from Michigan to California in summer of '06. Around 7,500 miles in 2 weeks. I didn't abuse the car at all. One thing that really peeved me was when AFR installed the 16 new guides, they wouldn't run the heads thru their CNC porting program to remove some obvious port interference from the new guides. This was the main reason I sent them back to AFR. I paid big extra $$$ for the CNC porting when new. These heads were over $3,000 in 2005, which accounting for inflation is over $4,700 in todays $$$$!! Guess I wasn't, and will never again be, a good customer.....

Z.06

OK so we are back to one and one for successes versus failures of aftermarket heads with my 20k mile criteria, and dmuellenberg has 60k on his OEM casting heads, which is an excellent mark. I hope my Greg Good rebuilt OEM heads can match this mark. I really would like to have a lot more data to help settle this discussion, and I have tried various techniques to get it. I have tired being nice to people and I have tried being somewhat insulting, even though this is not my nature. While the original thread starter's question was about failures of aftermarket heads, I really want data to support both successes and failures. I have not been bashful about disclosing a failure with my "fixed" OEM heads after only 20k miles. Please share your LS7 aftermarket head experiences with us on this forum. OK, now I am trying pleading.

grinder11

Since its introduction in 2006, many of us have seen, numerous times in numerous publications, the fact that just 10 years prior to 2006, the LS7 would've been considered a racing engine. In looking over the many posts of the problems we've heard about, my theory is that when you get to the performance level the stock LS7 is capable of, you're really pushing the reliability envelope. The few LS7 engines that make it to 6 figure odometer readings without a teardown are few and far between. They also have heads which have all the machining specs as close to, or within blueprint tolerances as possible. All the coatings and finishes are correct. Since virtually none of the parts are made in house by GM, they have little control over the parts quality. My belief is GM realized the only way to achieve the long term reliability horsepower levels they wanted was to stop going larger displacement, and go with FI. So if you want to have the LS7 in your car, its going to need more maintenance than an equally powerful FI engine will need. That's my opinion, FWIW......

FNBADAZ06

I think you're not going to get much data on this as most of the folks who switched to aftermarket heads have also moved on to different types of valves that will differ from stock....so you'll probably won't see the same type of failures related to breaking the heads off or dropping valves like the OEM can/has done.
You might gets some results from reported valve guide wear on certain aftermarket heads which were modeled after the OEM.....