MTPZ06

Cool, let me know...I wouldn't mind checking out Kohle's shop as well.

American Heritage

We still get lots of calls on how to do the wiggle test so we thought we would bump this thread. It used to be a sticky till some forum member greatly missunderstood what a wiggle test is.

A wiggle test is: A go or no go Test. Plain and simple.

Feel free to give us a call 310-326-2399 if you have any questions or need any additional support performing your own wiggle test.

Kouasupra

Great write up AH.

Buzartiano

Ttt worth moving up again awesome write up

American Heritage

We were told by two separate people this week that this write up helped them and that they found this write up/DIY via their google search.
We wanted to bump this DIY since those individuals found this write up helpful and hopefully some other forum members may find it helpful as well.

encasedmetal

I didn't see where you responded to the questions on what to do with the readings. Are the dial indicator readings to be divided by 2, or mult. by 0.62 or are they what they are? thanks

American Heritage

We have found that the wiggle test readings are roughly half of the actual mic and bore measurements.

Use this formula:
Wiggle test measurement on dial indicator divided by two then minus .0005". That will get you very close to the actual dial bore and mic measurements.

Vette @ 71

This question has been asked before but no response.

Would be interesting if you would show some examples of your wiggle test methodology results against actual dial bore and mic measurements on the same heads??

Much has been said about the efficacy of the wiggle and real data would help answer the question.

American Heritage

We think its a great idea to post a video of the wiggle test then of the mic/bore measurements.

We have a 2009 C6z06 with a GMPP warranty in the shop that failed its wiggle test today.
We made a quick video of the wiggle test while the heads are on the vehicle. Once the GMPP rep stops by to approve reworking of the cylinder heads we will pull the heads and make another wiggle test video with the head sitting on the bench. Then one final video of the head disassembled and mic/bore measurements. That way we can all see together the data of the wiggle test with heads bolted to the vehicle, wiggle test data with the heads sitting on the bench and then mic/bore data.
Give us a few days to post up the videos. It takes the GMPP rep a few days to come by and give the OK for repairs once the GMPP claim has been submitted.

MTPZ06

How my miles on this one Kohle?

American Heritage

30,100 miles, One owner all street miles.

Vette @ 71

Excellent!

olddragger

continue to be impressed by american heritage

sam90lx

Gizmo5

AHP doing it right as usual. Just sent this to my buddy in Alabama too. He just bought a Z and I'm telling him to send his heads your way Kohle.

bambihunter

Forgive me if I'm ignorant of some new development....but I recently read in this forum that GM has disavowed the wiggle test; how is it you are still getting the GMPP folks to accept your results?

Don't get me wrong...it makes good sense...but I didn't think GM had much of that left.



bambihunter

stefuel

I wouldn't know Kohle if I tripped over him. (I'm 60 years old and trip over a lot of things). But I've read enough of his posts to believe he knows what he's talking about. I'm old school. I don't need a dial indicator to tell me if the guides are bad and I'm pretty sure Kohle does not need one. The "wiggle test" is nothing new to valve work. That has been around longer then me. It was pretty much the way everyone has done it since the invention of the internal combustion engine. The only reason to waste the time measuring it is to convince the bean counters to pay the bill.

pewter50vette

65 years old trip on many things, you hit the nail on the head it is all about the dollars with gm , the z06 he is talking about is mine just street driven owned since new plan on keeping it makes since to have heads done if nothing else for peace of mind as it turns out they needed to be done, I know my car is in good hands, will have to decide which package to go with leaning towards port polish package # 4 , it will interesting to see how far out of spec they are will post after work is done and put a few miles on her .

stefuel

"However, the wiggle test has been discredited since it is difficult to do properly so there is a strong possibility that it will result in a false positive or a false negative. The only reliable way to check the guide clearances is with a valve guide bore gauge to measure the guides and a micrometer to measure the valve stem diameters. That means pulling the heads."

This is Bills post. It is accurate. In the eyes of GM it's how the clearance is measured and provided to GM for proof. Regardless of how it's measured, a worn guide is a worn guide. I'll bet my left nut that I could put a head on the bench with a combination of good and bad guides with valves installed and springs removed. Then have the least mechanically inclined person I could find look at the head and confirm which are good and which are bad. It's not rocket science

#1 moves up and down freely with no side to side movement OK
#2 moves up and down freely with a little side to side movement????
#3 Ohhh crap, this one is bad.
Why do you say that?
Well it moves up and down freely but it's like throwing a hot dog in Yankee stadium

American Heritage

We have a very good relationship with GMPP (and other warranty company's as well).

We show them the data and they approve it or disapprove the claim based on the data.

The wiggle test is a decent/good way to tell if the guides are done/out of spec or not. Its not a scientific test and is not treated as such. It is treated as a go or no go test.

In the past we have done the wiggle test for GMPP representative, auditors and managers then pulled the heads and had GMPP come back in to the shop and observe us as we performed the actual mic and bore gauge measurements. The results of both tests was validation for them to allow the findings of the "wiggle test" here at our shop. I cannot speak for other shops/dealerships in regards to their relationship and validation of their data with GMPP.

It also does not hurt that we are a true late model Corvette specialty shop. We usually have 4-10 C6z06's in our shop at any given time. GMPP has even used us a third party source to verify and diagnose other issues from dealerships.