cdngolfer

These post regarding potential dropped exhaust valves are getting to me. I want to track my 08 Z06 with 20,000 miles on it again but am too worried about blowing it up.

Input on using reworked Z06 heads vs new would be appreciated please. Use the same GM valves, new GM valves ($2400) or SS valves (add $350)? PRC heads were quoted for $3000 plus re and re. (At least my heads will be worth about $1300).

Do I need a trunnion upgrade on an 08 (extra $350)?
New push rods?

I will get double springs, Ti caps etc., and mill the heads 10 thou ( I run 94 Octane)

I can justify this as the value of the car might increase and I will have peace of mind.

One other thing - I sure would like a cam for the lope and a bit more power. Including a custom grind cam that will pass emissions, (or any grind and a retune for emissions testing every 2 years) CR5 timing chain and install, its about $3000 in addition to the head install. (I am near Toronto so > $$). Can't really justify this as the value of the car may not increase. (I have no plans to sell it however). Road and Track did a head comparison that I have to search for here and in my magazines.

It seems that the cam install during head replacement is not going to save much $$, surprisingly. ATI underdrive pulley replacement was recommended for $650 more.??

I am sure others here have thought about this, so experienced drivers, please jump in. Thank you.

TheDingo

Is there a way to machine or change parts on the stock heads that would remedy the potential failure that others are experiencing in regard to dropping valves?

Just curious because this may be a cheaper alternative to upgrading the heads as a whole. Although, I can imagine it's much easier justifying heads to the wife when you tell her it's not a mod it's maintenance haha!

stealthy08

I am having my existing heads cleaned/tanked, clean port heads, mill surface, ss exhaust valves, bronze exhaust valve guides, competition multi angle valve job, reassemble with dual valve springs, Ti retainers, Gm hi performance head gaskets, ARP pro series head bolt kit, and the comp cam trunion upgrade. Its costing me 4k because they have to remove, inspect, then re-install my supercharger so that labor is added in. Dyno pulls before and after are added in along with re-tune.

I'm not after more horsepower, just get the dropped valve scenario out of my mind even if not completely.

My question is, should I consider the intake valve too?

GMuffley

Whatever you choose, don't use GM valves for you rebuild. Definitely SS.

cdngolfer

Thanks for that. The shop that I will likely use will do all that to the present heads. I will change to SS valves. I will ask for the ARP bolts. I will see how much porting is.

propain

Based on what?

RedZ4me

Find my recent thread,

I did PRC's-milled 20 thou with Ti/SS exh, custom cam with 8 deg overlap, MF103, Trunnion upgrade, ATI stock diameter unit, all new hardware etc..... 525 rwhp thru full stock exhaust. Runs good Give Manny @ DaSilva for help if you need it. I can run 91 but run 94 as you.

Personally, I would if I were you recoup some of the costs selling the stock heads....I don't trust they were machined correctly anyways and PRC's flow better.

1BDRSK

Give Rob at Champion a call. He's always been really helpful whenever I had a question about what to do about my heads on my motor.

softy91

For the reasons mentioned above I did exchange heads because I have a little over 6k miles on the car most street/hiway it was time to do something or save up for new heads to bolt on or more depending on damage. I had 3 exhaust valves that had worn the guides and all the rest checked out to well within tolerance.

Was it worth it? I really don't know, but I was ready for some serious power and this was a great excuse to spend lots of money on something never seen but will put a real smile on your face just touching the loud pedal. Having a reputable head shop install bronze valve guides and do other upgrades will be cheaper than buying heads from your local dealer and will have most of the best flow characteristics that you cannot get from GM. I don't want to start an
argument about new vs aftermarket here but you will not always get the latest and greatest from GM parts, the technology doesn't get to the dealer parts stream as fast as it gets to the streets.
I went with bronze valve guides, which is what GM should have done when they manufactured these heads. I also went with the trunion upgrade and FERRA exhaust valves as my Intakes speced as new they were polished and re-used. The bare heads were CC ported to stage 2 race specs.

I also found out why my stock engine made more power than most other LS7s, the pistons were 12 out on the deck hight which is the max. allowed. Nothing like free power.

I also had my heads trued up and cut to 67cc yeilding 11.7/1 compression ratio.

Mark2009

That's the baffling part right there. I have heard of similar cases (6 out, 2 w/in new specs).

Sneaky

cdngolfer

Thanks!

I just spoke with RedZ4me who is local. He said that the cause for my clutch pedal going to the floor may be the master which I will replace with a Tic. I have an LS9R clutch that I was going to put in but I will try the Tic first to see if it solves the problem. If it does, I can sell the clutch and Lingenfelter aluminium flywheel (save on the install) and get porting done and a cam!

GMuffley

That's what WCCH and most after market vendors use.

propain

Most vendors use WCCH.

You just seem to make a strong statement of MUST as if there was some kind of conclusive data that the OEM valve wasn't a good option if the guides were replaced with Bronze.

Katech, probably the biggest vendor on here, doesn't use SS valves. Haven't seen any of their builds with bronze guides and OEM valves drop a valve yet. Id say thats as conclusive as the use of SS.

AzDave47

Katech does have WCCH do bronze guides, but use specially coated Ti intake valves although they do use the factory exhaust valves. It's something like $1100 for the new specially coated Ti intake valves. Katech also offers similarly coated Ti exhaust valves instead of the factory two-piece sodium cooled exhaust valves if you want to splurge and go even lighter on the valve train

GMuffley

I don't recall using the term "Must" and I am aware of Katech's work. I don't see what the argument is about.

'06 Quicksilver Z06

Interesting, your selection of the Ferrea valves. Ferrea Superalloys, I presume.

That exhaust valve is pretty popular in here, and is on the listing that I keep of members in here running a heavier than stock exhaust valve, be it solid stainless, inconel, or the Ferrea Superalloy.

I have noticed that tjwong, another well respected vendor in here, runs it in his personal car, and in some of his builds.

http://forums.corvetteforum.com/c6-z...med-the-z.html

I read a lot of posts from members on this forum running a heavier exhaust valve than stock.

I came accros this Katech Street Attack LS7 owner, jkrlucas, I believe that this car may have been "Katech Street Attack #40", and he had switched from the Katech recommended hollow stemmed stock exhaust valves which came in his Katech engine, to the Ferrea Superalloy exhaust valves. He also mentions both Richard of WCCH, and Tom (tj) Wong in his post and in describing his reasoning for changing to the Ferrea valves when asked, that reasoning apparently being in his words, "just to be on the safe side".

Can't say that I blame him.

http://forums.corvetteforum.com/c6-p...post1583451040

I also recall the case of RichRichZ06, who lost his original engine to a dropped valve, and replaced it with a Katech short block that he purchased and had shipped to him.

His new engine build, using that Katech short block, has a set of WCCH heads atop it with solid stemmed SS valves in them Valves which he indicates got there by happenstance. He has run this setup for somewhere around 2 years now, electing to leave the heads with the solid SS valves on, again, can't say as I blame him, and I see where he has reported no problems.

My point is that even with some of these Katech motors, the owners end up using an exhaust valve which is not "recommended" by Katech, and apparently have not suffered for doing so.

I look at those examples, and I'm in awe. Even Katech built engines will run, and run quite well with the non stock exhaust valves too.

At any rate softie91, I will get your name up on "The Registry" of LS7 owners in here who have decided on running a heavier than stock exhaust valve.

http://forums.corvetteforum.com/c6-z...st-valves.html

z0sicktanner

I'm running that setup as well

LS9Drew

Kind of funny katech is held in such high regards on here yet can't tune cars and have to have WCCH do their heads for them yet Katech knows more than everyone about heads and the components to use.

'06 Quicksilver Z06

Yes, I almost forgot.

Lot of guys in here running that setup with success, even though that is a 108g valve I believe, right?

JUSTAC6

can't tune cars? I'm new to vettes only had 2 in about 12 months but I have yet to read anything negative towards them.