In this installment of Project Factory Five Cobra, we’ll be discussing replacing the timing cover seal on our Ford 302 small block engine. The timing cover seal is designed to seal the engine and keep oil from escaping. The seal has a metallic outer body and is pressed into the timing cover. As these seals age (our 5.0 engine is from a 1988 Ford Mustang), they harden and start to leak. As the motor is apart and fully accessible outside the vehicle, now is a great time to replace the seal.
The timing cover seal is frequently installed by using a combination of a dead blow and a block of wood. The block of wood is placed over the seal and the hammer is used to knock the wood. This is risky because it is easy to irreparably damage the seal if all parts are not correctly aligned. A compromised seal will lead to a leaking engine again, right where we started.
Another installation method is to find a press or special tool of some type and attempt to carefully seat the seal in the timing cover. A quick Internet search did not reveal a specific tool for Ford 289/302 engines. Without an affordable and easy to obtain tool, we set about creating and 3d printing our own tooling.
Here, we wanted the tool to be strong, so we decided to use polycarbonate filament. Polycarbonate is a thermoplastic polymer containing carbonate in its chemical structure. It is used in engineering applications for strong, tough materials and forms the basis for bullet-proof glass:
To save time, energy, and space, we’ll use a desktop 3D printer. In this case we’ll use Airwolf’s EVO 3D printer because it can print in polycarbonate and operate in an office environment with its carbon and Hepa air filtration package. The EVO is also compatible with standard 120V wall voltage and incorporates chamber heaters to print polycarbonate correctly. When 3d printing polycarbonate, high temps are the key, with bed (160C), extruders (300C), and chamber (70C) at the maximum range of desktop machines.
Designing the part is straightforward. We matched one side of the tool with the timing cover seal, and the other with the harmonic balancer washer. We also dimensioned the internal cavity at just slightly larger than the crankshaft journal:
We then converted the tool to an STL file and placed it on the bed of our EVO. We selected polycarbonate as our material, and set quality to “Draft” because we are not overly concerned with surface finish, choosing to focus more on minimizing print time. We choose high strength settings to make sure the tool would be up to the pressure of pressing the steel seal into our aluminum housing. Finally, we stuck with the .5mm nozzle as this comes standard with the EVO, and 3 hours for an overnight print is reasonable (larger nozzles would save significant print time):
The next morning we came into the finished tool. Because of the simple design, we did not need to remove any support structures, the angle of the tool being well within the self-supporting geometric capabilities of the EVO. The part also quickly released from the bed because of the temperature sensitive nature of our Wolfbite Mega bed adhesive. In particular, the Wolfbite adheres the part to the glass print surface when hot, and releases the partwhen the plate cools down, after the print is completed.
The timing seal installer fit nicely. With a few turns of the nut, the seal was installed successfully.
The following video shows the tool in action.
To learn more about the benefits of combining in-house 3D printing and tooling please contact one of our additive manufacturing experts by emailing firstname.lastname@example.org
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