ctsv510

Updated

hot-toy

Please Add me to the list.

Stock 2008 Z06 with 13,500 miles
all (8) exhaust out of spec, (3) intake out of spec (5) intake only in spec by .0001-.0004
Measurement done by Katech/WCCH
can provide data if needed

ttx350z

My valves where bad as well, I can feel movement with the valve springs still installed. But Todd said they weren't nearly as bad as yours. Crazy since mine has over 43,000 miles on it with stock cam/valvetrain.

I have the heads in my garage if you want to check it out before I send them back for the core refund.

Dirty Howie

Can you take a video showing how loose they are ?


DH

ttx350z

Just made it a few minutes ago!

Dirty Howie

Yes and I just watched them 30 seconds ago

Like I said in other thread. Hopefully you will match up the actual measurements to the video

Thanks !!


DH

Bill Dearborn

Don't think the valves will not move on an in spec valve guide.
I didn't video the movement of the valves after the shop measured my guides with a guide bore gauge but afterwards I installed valves in some of the guides that were well within spec along with some in the guides that were out of spec. Even the guides that had clearances around .002 allowed the valves to wiggle to some degree.

https://www.corvetteforum.com/forums...post1589205160

A wiggling valve isn't necessarily an indicator of a bad stock guide, it depends on how much it wiggles. The guides that were out of tolerance allowed the valve to wiggle a lot. The guy that owns the shop that is working on my heads it takes a lot of experience to grab the valve and feel how bad the wiggle is.

Bill

KP-C6Z

Yep, Mine were way out.

jwebsta32

Pulled the trigger today and talked to Kohle at AH and ordered a set of their Package 4 heads!

AZDANZ06

soldier4life

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2011 C6 Z06
40k miles
Bone Stock
street driven (maybe once a week)
Test done by: American Heritage Performance

Here's the numbers:
#1 exh .0065"

#1 int* .009"

#3 exh* .005"

#3 int* .0075"

#5 exh* .006"

#5 int* .010"

#7 exh* .0075"

#7 int* .011"


#2 exh* .006"

#2 int* .010"

#4 exh* .0055"

#4 int* .009"

#6 exh* .0065"

#6 int* .0095"

#8 exh* .007"

#8 int* .010"

chadyellowz

Wow under spring pressure and the valve in the seat to see this much movement your a lucky guy indeed. guessing from what i see they're all out of spec by a good bit the worst ones i'd say have at least .0130 or more, post up if you get the spec back, nice catch

ignatz

Driven vigorously but not to extremes. No track, just a few autocrosses. Doubt I've ever gotten to 7K.

N/R means “No reading” (Quote from proheads.com - WCCH) "It was off the scale so bad we were unable to get a reading.



In for new guides, SS exhausts, beehive springs.

These are all "hourglass" shapes which must mean something about the forces applied to the valve stem. Probably these wear patterns are ovals and their orientation would suggest something about the rocker geometry.

"GM, where's your pride? Where are your engineers?"

crAzy

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2006 C6 Z06
52,000 Miles
Daily driver (25 miles a day average it sees)
Mods:
Cold air intake
Deleted mufflers

Shop measured one intake and one exhaust

Intake - .013
Exhaust - .030

Drove the car 32K miles before checking the heads. Luck is on my side.

dmuellenberg

Just to clarify, based on the information you posted in another thread, these measurements were from a wiggle test. From other results comparing the wiggle test to actual heads off measurements you should divide the wiggle test measurements by roughly half, so the intake would be around .0056 and the exhaust .015. These measurements, especially the exhaust, are still on the extreme side. This also assumes that the wiggle test was done accurately as GM claims that a wiggle test measurement is difficult to perform accurately with the heads still on the vehicle.

crAzy

Ahh ok. Yea I didn't keep up with the test procedure after seeing the wiggle test with the gauge installed was done. He told me he was only changing out the exhaust valves and install all new guides which is right? He told me the intake valves are made out of stainless so those are good to reuse. Don't think he is wrong as he is a reputable shop and has been mentioned many times on here.

RamAir972003

I'm curious where you get your information from...I have a fresh set of heads here at home none of the valves wiggle like his did...like I said before this is an issue that is affecting all years 2k miles 64k like mine....chances are you check the heads by doing the wiggle test like in video above chances are they are out of spec period...moving like that..maybe not bad maybe real bad..its not worth taking a 15k gamble.

crAzy

You guys can add me to the list if it still gets updated. I posted my results a few replies up.

hhntr111

Garye, My 427 vert had about 7500 miles last fall when I had Blackstone analysis done, no unusual metals content. When you did your heads, how did you handle the warranty? My valve train ticks, like everyone else's, but no oil usage, pulls great.

Steve07

CTSV510 - excellent post. Very informative. It appears you have manufacturing experience. Thanks.