C6Z06 Owners: valve guides fixed?
 

Hello,

Post here if you’ve had your valve guides repaired, which company and if you’ve needed secondary repairs or had the dreaded catastrophic engine failure.

Please note your other mods particularly non OE cams valve springs or valves, and usage.

If you know your valve lift and duration please list.

I know this is a bit repetitive from my prior post but I want to keep the data as clear as possible.

if you haven’t already posted to the c6z current or prior owners thread, please do if you don’t mind.

Thanks for your cooperation and all that have taken the time to participate.

https://www.corvetteforum.com/forums...n-a-c6z06.html

Advanced Induction heads by RPM.

100% stock otherwise.

Street car.

2008 Z06 with 17k miles. Did the head fix at 15.5k miles. I went with AHP package 4 heads. PM guides, Ferra exhaust valves and tumble pushed intake valves. In other words my car is stock. Heads were beautiful when arrived and the swap was pretty easy. Also Kohle at AHP was very easy to work with and was very happy to talk to me and answer any and all questions I had. He made the recommendation on my head setup based on what my future plans were. I liked that they didnt try to upsell me on other components.

2009 Z06 with 49k miles. Fixed heads at 48k miles. AHP package 4 heads. No upgrades.

10,000km (6k miles), done as precaution. AHP pkg 4...stock. Turns out originals had a couple guides just barely out of spec. I feel better, do a few track days with the car. AHP were a pleasure to deal with...almost zero downtime, returned cores. gorgeous
https://cimg2.ibsrv.net/gimg/www.cor...47720587cb.jpg

Looks like your going to see an overwhelming response to use of the AHP heads.

I went with AHP as well, and am very happy with the results. I choose each specific part in my build with a bunch of help and guidance from Kohle and a handful of others on this thread. Not a part I would change if I were to do it over again.

I'm a little nervous as of late about a couple of other threads that we don't have any clear conclusion as to why those heads may have failed. I'd like to learn a little more about what the process for inspecting Ti intake valves before determining whether or not they can safely be reused. I believe they are sent out to Del West for tumble-polishing which is something Del West began doing at the request of GM on their Ti intake valves for the LT4 that came out in 2015. I believe Katech only uses new ($190 each) Ti/Mo valves (both intake and exhaust) for use with their bronze valve guides in their builds, but most shops reuse the OE Ti intake valves from Del West so long as they are able to, (or they just go to a solid S/S intake valve and significantly increase the valvetrain mass.)

I'd also like to learn a little more about the different clearances AHP may have used on the Moldstar 90 valve guides over the years. My heads were done somewhere around the early to mid August 2017 time frame. I probably only have about 1,100 miles on the heads in about 15 months since they have been swapped. Two dyno sessions to get the tune where I wanted it. About 7,400 miles total on the odometer. Runs smooth and effortlessly, idles around 850rpm and if nobody told you had an aftermarket camshaft in it, you probably couldn't tell. In my humble opinion, my motor is optimized for street/road course and is how GM should have done it from the begining! (but I don't think we'll ever see a V8 from the factory with camshaft lifts over .600"!)

https://cimg3.ibsrv.net/gimg/www.cor...4442157281.jpg

2012 Corvette Z06 LS7 7.0L 427²"
AHP Package 4 heads: PSI 1511ML springs, Moldstar 90 guides, Ferrea F2042p exhaust valves, high velocity street porting | CHE trunnion kit | TSP custom cam: 8620 core, 220°/244°, .635"/.635", 116 LSA, 113 ICL | Johnson 2110 SLR lifters | Katech C5-R timing chain | PowerBond PB1503SS | ARP Head & Crank Bolts | Airaid 252-216 intake | Corsa 14331 X-Pipe | Pat G. tune

07 Z06, valve guides replaced (preventative maint.) updated rockers at 120,000 km/ 75,000 miles May 2016. My Corvette mechanic had his machine shop do the work.
Main bearing broken fall 2017, bearings crank polished, and new rings at 149,000 km/93,000 miles. I also updated the oil tank plus baffle and larger oil pan added.
The car is stock but I track it a couple of times a year.
The car's been fine since.

Who did your heads list
 

Well I had a the sticky who did your heads but the mods took it down when they combined this page idk why we had over 1500

Good data base was lost ........

:cheers:
DH

X2. I am pulling my heads as we speak and at this point, the only decision I have left to make is MS90 guides or AHP's PM. I am not sure why AHP has been playing with the guide clearance if there has not been a problem at one end or the other of the clearance tolerance. If so, exactly how does AHP monitor that and how were those situations handled etc?

I would add, that everyone's (including my own) ports, valves etc look amazingly clean when taken off of the car although the guides are shot. What if all of our guide issues stem from not enough oil metering through the seal seal to lubricate the guide? If that were the case, I would expect eventual guide failure regardless of "who" does your heads. As that is pretty much exactly what you see (failures over time regardless of who does the heads) on this forum, FB pages etc., I think the seal used has to be part of the discussion. Maybe the MS90's self lubricating property allows it to survive under these conditions longer and AHP has found the combination of valve stem finish, seal, guide material and clearance that lasts longest??

2008 Z06 with 27k miles. Did the head fix at 24k miles. AHP package 4 heads. PM guides, Ferra exhaust valves, heads milled 0.20 with street porting.

2009 C6Z inspected heads at 15K miles, and 14/16 guides beyond GM service limits.
Went with AHP heads, MS90 guides, treated OE Ti intakes, Ferea F2042p hollow stem 1-piece ex valves, PSI 1511 springs w/TI retainers, and CHE rocker trunions. No port, no mill, stock cam.

Which threads didn't have clear conclusion on why they failed? I've seen a few over the last several months and they were using OEM intake valves in bronze guides which we have been advising against for years.

Yep... AHP 4... milled .30

My thread is here: https://www.corvetteforum.com/forums...-blown-up.html

To summarize: One of my rockers broke, one of my intake valves broke, all other intake valves in the head where the issue happened showed wear. One intake valve even had very noticeable cracks. All of that info and pictures are in that thread. I had AHP heads with Moldstar90 guides.