musicmankeb

Date of heads pulled: 7/5/12
Head Type: GM LS7
Year: 2006
Miles: 16,000
Track time: None
Tune: Stock
Mods: Haltech M103 + B&B exhaust for maybe 6,000 miles. Just put headers on the car within 300 miles and have been easy on the throttle since no tune. Car is currently at Katech getting stage 2 and these were the specs of the guides.

Gauge Valve diameter .3135"

Guide Clearances

Intake #1
Top .0027
Mid .0021
Bot .0024

Intake #2
Top .0030
Mid .0022
Bot .0028

Intake #3
Top .0025
Mid .0022
Bot .0023

Intake #4
Top .0030
Mid .0023
Bot .0025

Intake #5
Top .0033
Mid .0022
Bot .0027

Intake #6
Top .0028
Mid .0022
Bot .0025

Intake #7
Top .0029
Mid .0023
Bot .0027

Intake #8
Top .0030
Mid .0023
Bot .0028
=========================
Exhaust #1
Top .0022
Mid .0026
Bot .0069

Exhaust #2
Top .0022
Mid .0024
Bot .0048

Exhaust #3
Top .0020
Mid .0028
Bot .0064

Exhaust #4
Top .0022
Mid .0024
Bot .0039

Exhaust #5
Top .0021
Mid .0029
Bot .0085

Exhaust #6
Top .0021
Mid .0023
Bot .0046

Exhaust #7
Top .0021
Mid .0024
Bot .0054

Exhaust #8
Top .0022
Mid .0025
Bot .0033
=================

My observation, the exhaust valves on the left side of the engine (drivers side) 1,3,5,7 have more wear then the right side of the motor. Which makes me think oil could be a factor since that is the side furthest away from the oil sump. Regardless, every guide is out of spec on the bottom side.

Random84

what's the "spec" for clearances again?

Mopar Jimmy

Why do I know where this thread will end up?

Bill Dearborn

What are you going to do about the excessive guide wear and how much more will it cost you?

Bill

FrankTank

but maybe just maybe this can stay civil and merely be a list , certainly will be interesting to see results

musicmankeb

Max allowable clearance is 0.0037 for both intake and exhaust

Replace the steel guides with bronze guides, replace the exhaust valves with OEM, and replace the intake valves with Katech's moly coated. They are giving me a 1 year 12,000 mile warranty so they are confident in this route. If you want my honest opinion, I wish I would have gone with an aftermarket set of heads like Mast or PRC to rule out the head all together as being the problem. With that said though, my observations about the driver side having more wear could be related to oil. The car was not tracked either so that's something that makes me wonder.

Also Cylinder #7 is usually the one that has the valve drop on these because of fueling/tuning right....well my #5 exhaust guide was worn out the worst. So to me I don't think it's a fueling issue when it comes to the wear, sure that can cause failure but I don't think it's related to the wear of the guides.

Last thing, I would really appreciate if people post their stats like I have above and we can make a long list!

Very last thing, I'm not a professional engine builder but I'm not a dumb either but just take everything I say with a grain of salt. It's just my opinion but the numbers I have posted are all accurate.

HyperX

Mine is .000000001 all the way around!

Boooo Yaaa!

VicCaerter

I had a tech bring up the specs for measuring valve guides and it has a picture of a gauge clamped to a rocker post, measuring from the top. Long story short, you can get the spec measurements with the heads on. I took a picture of it too because no one around here believes anything anyone says.... specs are <= .0037"

musicmankeb

.0037"

Bill Dearborn

Don't know about the number 7 issue. I have been dubious of those claims for years. None of them make any sense. The exhaust valve in number 1 is what killed my engine. From the pictures number 7 cylinder didn't look any different than the other two undamaged cylinders on that side. Hard to tell what #1 looked like before the valve started banging around in it. Some of the other engines I have seen fail had their blocks ventilated toward the front of the block which I doubt indicates a failure in the cylinders at the back of the block.

Bill

Mopar Jimmy

Keep my warranty in check (have GMPP on my 2006 for another 3 years) and my car stock.

tim414

ConfusedGarage

Date of heads pulled: 6/1/12
Head Type: GM LS7
Year: 2006
Miles: 18,000 (cam and mods done around 5,000)
Track time: None (90 1/4 passes)
Tune: Yes
Mods: Was a Katech stage 1 car (full exhaust, torquer 110 cam, halltec intake supporting mods etc) done at ~5,000 miles; was 531 rwhp then


Guys, just a thought. If you want this to be informative and helpful rather than the train wreck previous threads, keep your opinions about warranties and other things irrelevant to facts and data to a minimum. If you don't have data to assist here, don't feel the need to just fill the air...

All of mine were in spec from my understanding.

[IMG][/IMG]

musicmankeb

I'd like to bump this thread for other people to post their numbers. Keep in mind that the bottom of the guides are where most of the wear is showing up, not the top (for those of you who are trying to measure without taking your heads off).

Sébast19X

If you look you're wear pattern, you will see that you have more wear in the middle than on the top.
That is a clear indication that you could have wear at the bottom of the guide.
In my case, because I'm a little pointed in this thresds, my middle measurement show no sign of wear and are equal on all cylinder.
This is just to be clear.

Thank you,

Beast5spdGTA

Date of heads pulled: 8/23/2012
Head Type: GM LS7
Year: 2007
Miles: 75,000 Engine and tune all stock
Track time: ~10 hrs at Sebring (~20 1/4 passes)
Tune: No
Mods: ZR1 clutch

Car always ate oil ~0.75-1 qt per 1000 miles with spirited driving (from 47K to 74 K miles), last two track days was more like 1+ qt per 100 track miles and smoking at start up (bad valve seals)

Last 3 days at Sebring had oil temps in the 240s to a max of 257 (IIRC) I'm a newbie at driving on a road course.

Valve guide wear: alot (not scientifically measured)
http://www.youtube.com/watch?v=Bi51kj51FvU&feature=plcp

The heads are being rebuilt right now, if I get numbers I'll post them.

Sébast19X

Yeah, clearly the guides was shot !!!
Thank for posting

08VRZ06

Here is the Spec sheet on my heads. It is a 2008 and at around 24,000 miles it had a warranty cam and lifter replacement in May 2011. At 31,000 miles in March 2012 I decided to add headers and a Katech 110 cam and associated parts. I bought the car with about 15,000 miles on it. I wouldn't say that I drove it hard, a few 6K shifts, a few tire spins but no smoking burn outs and I never tracked it. When I installed the cam and changed out the springs, I noticed what I would say was excessive valve stem in guide play mainly on the exhaust valves. I put it together any way and drove it about a month (less than a 1000 miles) and decided not to take any chances and pulled the heads and have them checked and redone by WCCH. This sheet I got from Richard at WCCH and this is the exact measurements of all of my valve guides. As you can see some were worn very badly....... This engine was built Nov 29, 2007 and the Z06 build date is Dec 11, 2007.



Mark

Dirty Howie

'06 Quicksilver Z06

Well, my valve guide numbers from my spare set of heads with 31k miles on them are back from WCCH



The bottom of every single exhaust valve guide is way out of spec.