Let's say I'm stranded somewhere, oil pan hit a rock. Need oil to keep going. All I have is a pine tree and a big kettle, so I can make tar. If I heat the tar up before pouring it into my engine (Let's say a Camry 2.5 4pot), would the engine heat be enough to keep it low viscosity enough to lubricate my engine? What's the viscosity of hot wood tar? Would this accelerate engine wear much? Is coal tar a superior lubricant as compared to wood tar?
Would coal (or wood) tar be an acceptable engine oil in a pinch?
- Thread starter Aston4
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Patman
Staff member
Is this a serious question?
Yes. I was reading about the history of ship building, and tar making is as old as history. I was wondering if it could be an engine oil? Olive oil and bacon grease work fine as engine lubricants, why not wood tar?
Wood tar was used to lubricate wagon wheels for thousands of years. If kept hot, I don't see why it wouldn't work inside an internal combustion engine.
Sounds like a PF type of "Experiment".
No, it couldn't be engine oil.
PF?
Pure speculation.
Never be able to keep it hot enough. Soon as it started pumping through the cold aluminum it would harden up and stop flowing.
Never be able to keep it hot enough. Soon as it started pumping through the cold aluminum it would harden up and stop flowing.
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Grok had to scratch its head on that one:
Here’s a concise comparison of the lubricating properties of engine oil (circa 1950), coal tar, wood tar, and tree sap, focusing on liquefaction temperatures and lubricating abilities at typical engine block temperatures (around 200–250°F or 93–121°C).
---
### Engine Oil (Circa 1950)
- **Liquefaction Temperature**: Already liquid at room temperature (derived from crude oil via fractional distillation, processed to remain fluid above -20°F/-29°C).
- **Lubricating Ability at Engine Temps**: Excellent. Mineral-based oils (e.g., SAE 30) with viscosities optimized for 200–250°F provided strong boundary lubrication, reducing friction and wear (friction coefficient ~0.1–0.15). Additives like ZDDP were emerging by the 1950s to enhance performance.
- **Notes**: Designed for engines, stable at operating temps, though prone to breakdown above 300°F (149°C).
---
### Coal Tar
- **Liquefaction Temperature**: Becomes workable around 176–212°F (80–100°C), fully liquefies above 392°F (200°C) depending on composition (high in aromatics).
- **Lubricating Ability at Engine Temps**: Poor. Viscous and sticky at 200–250°F, it lacks fluidity for effective lubrication (friction coefficient ~0.3–0.5). Better suited as a sealant or precursor for synthetic lubricants (e.g., via coal liquefaction processes like Fischer-Tropsch).
- **Notes**: Not practical for engines; decomposes and leaves residue at higher temps.
---
### Wood Tar (e.g., Pine Tar)
- **Liquefaction Temperature**: Softens at 122–158°F (50–70°C), liquefies around 212–302°F (100–150°C) via destructive distillation.
- **Lubricating Ability at Engine Temps**: Moderate to poor. At 200–250°F, it’s viscous and sticky (friction coefficient ~0.2–0.4), offering some lubrication for low-speed, heavy-duty applications (e.g., wooden bearings), but it degrades and gums up under sustained heat.
- **Notes**: Historically used as a crude lubricant, but unstable and inefficient in engines.
---
### Tree Sap (e.g., Resin-Based)
- **Liquefaction Temperature**: Varies widely; softens at 86–140°F (30–60°C), liquefies around 212–392°F (100–200°C) depending on water content and species (e.g., pine sap).
- **Lubricating Ability at Engine Temps**: Very poor. At 200–250°F, it’s either too thick or evaporates, leaving resinous deposits (friction coefficient >0.5). Lignum vitae wood, saturated with sap, self-lubricates in low-temp, wet conditions, but not in engines.
- **Notes**: Natural viscosity unfit for high-speed machinery; burns or hardens under heat.
---
### Summary
- **Engine Oil (1950)**: Best lubricant at engine temps—low friction, stable, purpose-built.
- **Coal Tar**: Too viscous, poor flow, impractical for engines.
- **Wood Tar**: Marginal lubrication, degrades quickly in heat.
- **Tree Sap**: Ineffective, sticky, and thermally unstable.
Engine oil far outperforms the others due to its tailored viscosity and thermal stability at 200–250°F. Tars and sap lack the fluidity and durability needed for engine blocks.
Here’s a concise comparison of the lubricating properties of engine oil (circa 1950), coal tar, wood tar, and tree sap, focusing on liquefaction temperatures and lubricating abilities at typical engine block temperatures (around 200–250°F or 93–121°C).
---
### Engine Oil (Circa 1950)
- **Liquefaction Temperature**: Already liquid at room temperature (derived from crude oil via fractional distillation, processed to remain fluid above -20°F/-29°C).
- **Lubricating Ability at Engine Temps**: Excellent. Mineral-based oils (e.g., SAE 30) with viscosities optimized for 200–250°F provided strong boundary lubrication, reducing friction and wear (friction coefficient ~0.1–0.15). Additives like ZDDP were emerging by the 1950s to enhance performance.
- **Notes**: Designed for engines, stable at operating temps, though prone to breakdown above 300°F (149°C).
---
### Coal Tar
- **Liquefaction Temperature**: Becomes workable around 176–212°F (80–100°C), fully liquefies above 392°F (200°C) depending on composition (high in aromatics).
- **Lubricating Ability at Engine Temps**: Poor. Viscous and sticky at 200–250°F, it lacks fluidity for effective lubrication (friction coefficient ~0.3–0.5). Better suited as a sealant or precursor for synthetic lubricants (e.g., via coal liquefaction processes like Fischer-Tropsch).
- **Notes**: Not practical for engines; decomposes and leaves residue at higher temps.
---
### Wood Tar (e.g., Pine Tar)
- **Liquefaction Temperature**: Softens at 122–158°F (50–70°C), liquefies around 212–302°F (100–150°C) via destructive distillation.
- **Lubricating Ability at Engine Temps**: Moderate to poor. At 200–250°F, it’s viscous and sticky (friction coefficient ~0.2–0.4), offering some lubrication for low-speed, heavy-duty applications (e.g., wooden bearings), but it degrades and gums up under sustained heat.
- **Notes**: Historically used as a crude lubricant, but unstable and inefficient in engines.
---
### Tree Sap (e.g., Resin-Based)
- **Liquefaction Temperature**: Varies widely; softens at 86–140°F (30–60°C), liquefies around 212–392°F (100–200°C) depending on water content and species (e.g., pine sap).
- **Lubricating Ability at Engine Temps**: Very poor. At 200–250°F, it’s either too thick or evaporates, leaving resinous deposits (friction coefficient >0.5). Lignum vitae wood, saturated with sap, self-lubricates in low-temp, wet conditions, but not in engines.
- **Notes**: Natural viscosity unfit for high-speed machinery; burns or hardens under heat.
---
### Summary
- **Engine Oil (1950)**: Best lubricant at engine temps—low friction, stable, purpose-built.
- **Coal Tar**: Too viscous, poor flow, impractical for engines.
- **Wood Tar**: Marginal lubrication, degrades quickly in heat.
- **Tree Sap**: Ineffective, sticky, and thermally unstable.
Engine oil far outperforms the others due to its tailored viscosity and thermal stability at 200–250°F. Tars and sap lack the fluidity and durability needed for engine blocks.
Awesome!!!!!!
Thank you. Wood tar it is then, until I can get back to civilization and swap out for bacon grease.
Well if I had planned on the hole in the oil pan, I would have brought along a welder and a pig.
You should ask Project Farm this....
If this is of concern why not run a graphited oil, that possibly can keep going for tens of miles after the sump was drained?
Everyone knows you’d have to find a lake and catch some fish. Use fish oil as engine lubricant and get your daily balance of omega 3 at the same time!
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I think that given the results of using any of these (engine rebuild for sure), you'll be just as well running the very best oil you can find in the first place, plugging the hole to avoid ingesting external debris when the thing breaks and you lose your oil, and run the engine on whatever of the original oil has remained in the system.
Unless you have taken care to let the engine idle for a bit after you broke your pan, so it can drain completely - you'll still have some oil left in the system and once it's gone, while it won't be good - it also won't be like you poured sand in the engine. There will still be some of them magic additive coated around parts, dying an heroic death in the name of your trunk refusing to carry extra oil.
A silly question deserves a silly answer.
I say try it and let us know the results.
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