“What I Learned Today” With Jeff Smith — The Right Tool For The Job

We were on the dyno at Kenny Duttweiler’s engine shop abusing a pump gas 383ci small-block Chevy at about 5,500 rpm when suddenly the dyno room filled with steam and water soon covered the floor. Once we shut the engine down and turned off the water, we discovered a brass freeze plug lying on the floor of the dyno cell. We were a bit surprised and more than a little embarrassed. Of course, what would have been worse is if this had happened at full speed on the drag strip dumping water under the back tires at 120 mph! Duttweiler said, “You probably installed that freeze plug with a large socket and a hammer, right?” This was exactly how we had beat that plug into place.

Duttweiler said that because brass is so much more expensive, the companies making these plugs have made them much thinner to save money. When the plug is installed with a large socket pushed into the bottom of the plug, this distorts the plug and pulls the walls inward, making for a very tenuous seal.

Our solution was to build a custom, stepped freeze plug tool that has a stepped mandrel a few thousandths of an inch smaller than the inside diameter of the freeze plug itself. This allows the tool to drive the plug from the face of the outside diameter of the plug, while supporting the inner walls of the plug, to prevent deformation.

The tool’s mandrel needs to be tapered so that when the brass constricts when installed into the block, that it does not pinch and capture the tool, which makes it difficult to pull the tool from the freeze plug. Our tool is double-sided aluminum fashioned by a machinist friend. The center on both ends is drilled and tapped to accept a long threaded steel handle that screws into the driver. A steel tool might be even better since steel won’t distort like our aluminum tool has over time.

We had our machinist buddy build a simple aluminum driver with two ends — one for small-block and one for big-block freeze plugs.

About the author

Jeff Smith

Jeff Smith, a 35-year veteran of automotive journalism, comes to Power Automedia after serving as the senior technical editor at Car Craft magazine. An Iowa native, Smith served a variety of roles at Car Craft before moving to the senior editor role at Hot Rod and Chevy High Performance, and ultimately returning to Car Craft. An accomplished engine builder and technical expert, he will focus on the tech-heavy content that is the foundation of EngineLabs.
Read My Articles

Horsepower delivered to your inbox.

Build your own custom newsletter with the content you love from EngineLabs, directly to your inbox, absolutely FREE!

Free WordPress Themes
EngineLabs NEWSLETTER - SIGN UP FREE!

We will safeguard your e-mail and only send content you request.

EngineLabs

We'll send you raw engine tech articles, news, features, and videos every week from EngineLabs.

EngineLabs

EngineLabs NEWSLETTER - SIGN UP FREE!

We will safeguard your e-mail and only send content you request.

EngineLabs

Thank you for your subscription.

Subscribe to more FREE Online Magazines!

We think you might like...



Late Model LS Vehicles

Drag Racing

Muscle Car & Hot Rods

EngineLabs

Thank you for your subscription.

Subscribe to more FREE Online Magazines!

We think you might like...

  • Late Model LS Vehicles
  • Drag Racing
  • Muscle Car & Hot Rods

EngineLabs

Thank you for your subscription.

Thank you for your subscription.

EngineLabs

Thank you for your subscription.

Thank you for your subscription.

Loading