Wiggle Testing: How to Perform On-Engine Test for C6 Corvette LS7 Valve Stem-Guide Clearance

Share This Page!

by Hib Halverson
© December 2014
No use without permission, All Rights Reserved

Let it be known: a “wiggle test”– measuring a Chevrolet V8’s valve stem-to-guide clearance with the heads on the engine–is not easy to accomplish. Done correctly, even for a professional service technician, it can be tedious, time consuming and even confusing at times.

No doubt, DIYs are reading this. If that’s you, know that we made some assumptions: 1) you have the Factory Service Manual for your car to explain preliminaries to a wiggle test which are not detailed in this article, 2) you have experience with engine work such that you can disassemble then reassemble your engine’s valve train and 3) you have access to and operational knowledge of the proper tools and measuring equipment. If you don’t meet #2 and #3, let a Chevrolet dealer or independent service shop familiar with GM V8s do the work.

Explanations of wiggle testing are posted in various places on the Internet and some are incorrect. Even the Factory Service Manual method is problematic in that, of the two drawings which show measurement of stem-to-guide clearance, the first shows a procedure which results in inaccurate measurements and the second, along with the manual’s instructional text, is impossible to duplicate on an LS7 head. Finally, if the measuring gear is not set-up and used properly, you risk inaccuracy. Such errors may have you decide a valve guide is worn when it is not. The suggestions in this article will result in the most accurate wiggle testing possible.

Full Story:  Wiggle Testing: How to Perform On-Engine Test for C6 Corvette LS7 Valve Stem-Guide Clearance

Related Forum Discussion:  Wiggle Testing: How to Perform On-Engine Test for C6 Corvette LS7 Valve Stem-Guide Clearance

(284)

Hib Halverson

Hib Halverson is an automotive writer and content supplier for print and internet media.

Share
Published by
Hib Halverson

Recent Posts

GM Set to Make Major Announcement about Bowling Green Corvette Assembly Plant

According to local news, GM is set to make a major announcement tomorrow, April 25th, regarding the Bowling Green Corvette…

24 hours ago

Corvette Action Center Introduces 2011 Corvette Z06 Carbon Edition Registry

Today, the Corvette Action Center rolled out a special online Registry for the 252 Carbon Limited Edition Corvette Z06 Corvettes…

6 days ago

Corvette Racing Team Takes 2nd and 3rd at Long Beach

CORVETTE RACING AT LONG BEACH: Second and Third in Another Thriller Garcia, Magnussen, Gavin, Milner all climb GT Le Mans…

2 weeks ago

Final C7 Corvette to Benefit Stephen Siller Tunnel to Towers Foundation

On the heels of officially confirming the 2020 Mid-Engine C8 Corvette to be revealed, on July 18th, GM has released…

2 weeks ago

GM Confirms: 2020 Mid-Engine Corvette Reveal on July 18th

Today, GM has finally confirmed the existence of the C8 mid-engine 2020 Corvette and that it will be revealed to…

2 weeks ago

Killeen, Texas Man Nearly Killed After Truck Drives Over his Corvette

Gerald Helmandollar, who had just picked up his new Corvette 45 minutes earlier is lucky to be alive after an…

2 weeks ago