LT1 Camshaft Swaps Made Easy


photos and text by: Michael Scano

We Put the MS Racing Components VVT Unlocker to the Test

Great things happen when two Long Island, New York based high-performance aftermarket companies join forces such in the case of MS Racing Components and JTM Motorsports.

JTM Motorsports’ quest for more power from their 2015 C7 Corvette shop car lead them to develop a custom camshaft package for the GM Gen V LT1 engine family. The goal from the onset was to retain the benefits of Variable-Valve Timing (VVT) Technology.

Upgrading to a high-performance VVT camshaft or developing a custom VVT camshaft profile with increased duration/lift piston to valve (PTV) clearances becomes an issue, especially with the exhaust valve when the camshaft is fully in the retarded (counter clock wise) position.  The high performance aftermarket currently only offers VVT cam phaser limiter kits. However, actual PTV clearance measurements are not known using these limiter kits and PTV can’t be measured since the cam gear phaser is locked without engine oil pressure.


MS Racing Components’ VVT Unlocker looks like the simplest thing ever but what it lacks in complex design makes swapping an LS or LT-series engines VVT camshaft so much easier.

VVT cam gear phases are computer controlled using pressurized engine oil. Without oil pressure, the VVT cam gear phaser is locked advanced making PTV clearance measurements in the full camshaft retard position impossible.

That is where MS Racing Components comes into the picture with their patent pending VVT Unlocker line of tools. The MS Racing Components VVT Unlocker allows for quick and easy unlocking of the VVT cam gear phaser without damage. With the cam phaser gear unlocked, it can be rotated counter clockwise (cam retarded) so PTV can be measured and verified.

JTM Motorsports was able to measure and verify the PTV clearances of their custom camshaft package using the MS Racing Components VVT Unlocker. Customers who purchase the custom camshaft package have a piece of mind that sufficient PTV clearances have been maintained while retaining the benefits of VVT Technology.


Teardown begins on the JTM Motorsports C7 Stingray, for the installation of their custom-grind bumpstick.



At this point, the JTM-spec custom camshaft is installed with the MS Unlocker tool in place of the OEM cam phaser bolt.



With the Unlocker tool held in place with a 7/8-inch wrench, air pressure is applied to the top of the Unlocker tool, unlocking the cam phaser and rotating the camshaft counterclockwise, then measuring the piston-to-valve clearances.



Unlocking the cam phaser is simple and easy. It’s a one-man operation designed to make simpler. The dial indicator is read to measure PTV while rotating the cam phaser counter-clockwise.



After the PTV clearances are verified the MS VVT Unlocker is replaced with the OEM cam phaser bolt.



The crew at JTM buttoned up the LT1, complete with ported heads and a custom-grind camshaft. Sure, you could have swapped the cam out without the MS VVT Unlocker, but it certainly made things a lot easier and much faster.

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