But MazdaMitch why not ABS?
Using ABS (Acrylonitrile Butadiene Styrene) for an under-hood thermal spacer—like a carburetor spacer or fuel pump insulator—sounds tempting (especially if you're thinking about 3D printing one), but it will quickly fail due to its specific chemical and thermal limitations:
- Low Heat Deflection Temperature (HDT)While ABS has a melting point around 220°C to 250°C, its Heat Deflection Temperature (HDT) is only about 80°C to 100°C (176°F to 212°F).
Intake manifolds and cylinder heads regularly sit well above 190°F to 220°F once the engine is fully warmed up and heat-soaked (and even higher right after you shut the engine off).
At these temperatures, ABS crosses its glass transition phase, turns rubbery, and loses its structural rigidity. Under the constant clamping pressure of carburetor studs or fuel pump bolts, an ABS spacer will warp, deform, crush, and create vacuum or fuel leaks.
- Zero Fuel and Chemical ResistanceABS is notoriously vulnerable to petroleum products.
Gasoline, raw fuel mist, oil, and solvent-based cleaners will attack ABS, causing it to soften, swell, crack, or chemically break down over time.
If a gasket leaks or fuel sloshes near an ABS spacer, the material will degrade rapidly.
What to use instead if you are fabricating/printing one:
If you need to make a custom spacer and are looking at engineering plastics or alternative materials:
Nylon (specifically Nylon 6 or glass-filled Nylon): Handles continuous temperatures up to 120°C–150°C, has great structural strength, and resists under-hood chemicals well.
Polycarbonate (PC) or PETG: PETG is slightly better with chemicals than ABS, though its heat resistance is still borderline. PC handles heat better but can still struggle with fuel exposure.
Teflon (PTFE) / Delrin (POM): Excellent chemical resistance and structural stability, though Delrin's temperature limit (around 85°C–100°C continuous) means it's better suited for fuel pump insulators than high-heat intake manifolds.
Phenolic Garolite (G-10 / CE): The industry gold standard. It is a canvas- or paper-reinforced epoxy/phenolic resin that laughs at engine bay heat, resists fuel completely, and doesn't compress or warp under heavy bolt torque.
So as you can read here hopefully, AI is useful at spreading out the details I already know.
I am the "trust me bro" source.
This is why I will not just 3d print these insulators out of ABS and try and make a quick buck.
I would not use it myself.
I know what needs to be used and finding someone to make it is the challenge.
