Uncledibble

Thanks Mark200x this is exactly the kind of post I had hoped for. I agree "ounce of prevention/caution" Next question would be who do I trust to perform the wiggle test.

'06 Quicksilver Z06

You can call around and ask if a dealership will do it.

Cost wise, I've seen anything from around $400.00-$864.00 to have it done.

Thing is, and part of what makes this matter as troublesome as it is, and things which have to be considered with your wiggle test are:

• You pay to have the wiggle test done, find out that one, or more, of the guides are out of spec, and end up having to pay the labor cost for pulling the heads, and the cost to fix the issue anyway, on top of what you just spent for someone to tell you that.

• You pay to have the wiggle test done and the guides are barely in spec.

At this point, you'll have to decide whether to go ahead and pull the heads at then, or wait and pay for another wiggle test to determine if you want to pull the heads at a later date.

• You "lose" the wiggle test, if you are in warranty, and the test comes back "good" and all of your guides are in spec. Under that scenario, you get to pay for the wiggle test.

• You "win" the wiggle test. There are two, arguably three ways to do this.

1. You have the wiggle test done, in warranty, find out that the guides are out of spec, and get both the test and the needed repair covered under warranty.

2. You have the wiggle test done out of warranty, and find that the guides in your 80K plus miles car are all well within spec.

3. Pay to have the wiggle test done, discover that the guides are grossly out of spec, and consider yourself lucky that you didn't have a mishap. Some would call this a "win". But you still have to pay for the labor and the repair on top of what you just spent to find out that your car was sick.

Of course in this scenario, you go back to the top scenario, where the heads would still need to be fixed, and whatever you paid to have the test done, would be in addition to what it would cost to address the problem.

Wiggle test is a great idea, but it's cost effectiveness has to be taken into consideration, because depending on who does it, it might not cost you much more in labor to simply have the heads pulled and examined.

But all in all, if you have the test done, here's to hoping that it goes your way.

Mark2009

Someone you already know/trust who will record the measurements and who has done it before or is at least willing to learn.

Post up your location and perhaps another forum member has experience with someone nearby.

If mechanically inclined I'd recommend doing it yourself.

JwT

Well there are things to look for. That little puff of smoke at start up is one. You can check by pulling your exhaust manifolds and looking for burnt oil around the stems. That's when I found that all the driver's side exhaust valves were bad at 68k miles.

Mark2009

1. Yes and no. There are several examples of worn guides and blown engines that exhibited no symptoms at all. The simplest and most accurate way to tell the condition of the guides is the wiggle test (beyond removing the heads), and it has the benefit of checking the intake guide clearance as well (we have seen a few of those way out of whack). Bottom line, lack of symptoms does not = lack of problems.

2. I'm sure you meant to say you found that the exhaust valve guides or exhaust valve stem seals were bad. Don't mean to nitpick, but the misinformation on certain aspects of this issue -- and please rest assured I am not accusing you of any -- does not need any reinforcement.
.

JwT

Well actually I had no symptoms at all, but remember reading this on some posts. When I bought the car with 67k miles in June of 12 I had already been reading the forum for a few months. So when I bought the car I drove it like there was an egg under the throttle. I just couldn't afford to buy the car and drop a valve a few months later.

It was a good thing I drove easy as I had a lot of issues early on that ate up extra cash. When I finally exchanged the heads for TS 265's is when I noticed the burnt oil caked pretty thick. I didn't even try the wiggle test as the heads looked like toast to me and I had already bought the new heads.

Uncledibble

It is fairly obvious I need to do the wiggle test based on the last 6-8 posts.

1. I am in the SE Valley outside of Phoenix Arizona.
2. I have pulled and installed motors on Trucks and Toyota FJ40's so I am fairly mechanically inclined, but do not mind paying an expert (trusted expert) to look at this considering the potential money on the line.

Zero smoke at start up, Zero smoke revving up the warmed up motor and zero smoke hammering on it up and on ramp. According to chase vehicle.

Thanks for the info

Mark2009

Unfortunately your odds of finding a trusted expert on the wiggle test issue is about 2 in 2 million (both of those 2 are GM dealers that employ forum members -- one in CA and one in NE).

I'd recommend you do it yourself. Give your experience, and assuming you are familiar with the way the valvetrain components are assembled and work, the Cliff Notes are:

1. Piston to TDC (just in case a valve drops).
2. Shop air (compressed air) into cylinder (car in gear, parking brake on, in case engine tries to rotate).
3. Remove both valve springs, tie off somehow (some use zip ties, I'm from KY so I used duct tape ). Retainers will likely be stuck to locks, will need to tap (whack lightly).
4. Remove shop air, test to make sure valves rest on piston and don't fall into cylinder. Should be about 1/4" drop, depending on how close you hit TDC.
5. Set up dial indicator on stem, below the valve lock groove.
6. Wiggle valve perpendicular to camshaft while holding the valve slightly off the seat, note dial indicator reading. Divide reading by two to get reasonable approximation of guide clearance).
7. Do both valves. On an LS7 the intake valve guide clearance will generally be pretty good as far as an LS7/9 is concerned (say .005 wiggle = .0025 clearance). This is a good crosscheck that you've got the dial indicator set up correctly.
8. Shop air into cylinder again, reassemble springs/retainers/locks/rocker (don't forget/lose the lash cap on the intake stem!!!)
9. Next TDC, next cylinder. Rinse, repeat... unless you find a bad one right off the bat. If so, go ahead and check the other side, you never know....

One caveat I learned here, if you use a claw type valve spring compressor be sure to use a small file or stone to dress the inside of the claw where it contacts the spring... any burrs or sharp edges could nick the spring which would likely make it fail after some use. Some won't use that type of compressor at all for that reason.

Service manual description: http://forums.corvetteforum.com/1582871091-post151.html (conventional forum wisdom is to divide the dial indicator reading by two to get reasonable approximation of actual guide clearance).