Can a gasoline engine run on diesel? If you’ve just used the wrong pump while filling up, this isn’t the question you should be asking. That’s because the differences in operating principles between these two types of internal combustion engines mean the shift is quite a complex task. However, if you still want to do it, we’re here to show you one of the most efficient ways of convincing a gas engine to work on diesel fuel.
While gas engines rely on spark plugs to ignite the air-fuel mixture, diesels use compression ignition, where high pressure and temperatures ignite the fuel. And this is why diesel engines have higher compression ratios than gas units (typically 18:1 to 23:1 vs. 10:1 to 14:1). Plus, gasoline engines come with lighter and weaker components, as their internals don’t have to deal with the enormous pressures generated inside diesel units.
Having highlighted some of the main obstacles that get in the way of such a conversion, you should know there’s nothing you can’t do when you have a garage loaded with tools, serious mechanical skills and the ambition of the folks over at the Garage 54 YouTube channel.
These Russian YouTubers are famous for mixing and matching (generally) cheap cars and their bits, in the same way you’d go about creating the perfect Subway sandwich… if you were an expert cook with a massive social media audience to feed.
Many of their creations naturally rely on Ladas, with their work ranging from 6×6 machines to simply replacing the studs in a tire with LEDs. As per their M.O., the crew didn’t use sophisticated technology in its attempt to convert a gasoline engine to run on diesel, but they pulled it off.
You’ll want a gas engine with an iron, not an aluminum block
The starting point for this experiment was a neglected ten-year-old Lada engine. The good parts? The iron engine block, the relative sturdiness of the components, as well as the facile maintenance.
The bad bits? Examples include worn-out pistons and cylinder walls, but none of that matters. That’s because the mechanics rebuilt the inline-four engine, boring the unit and fitting it with larger pistons.
And this wasn’t some rushed job to make everything seem like it would work on camera. Instead, they completed the said first stage with a two-day cold break-in period of the engine, which did require a few tweaks to the oiling system.
As opposed to a hot break-in where the engine would actually burn fuel, the oil making it past the cylinder heads remained unburned, so it didn’t end up clogging the piston ring area and increasing the damage to the engine. So, even without the fuel shenanigans we have here, using a cold break-in procedure for your rebuilt engine can be beneficial.
Increasing the compression
The mechanics machined the cylinder head and block, while using a multiple-layer metallic gasket between them. This allowed them to more than double the compression, with a post-modding test showing 285 PSI (!) in the cylinders of the naturally aspirated engine.
To keep all that pressure in, the pistons were also machined, with new grooves added in order for the units to go from three to six piston rings. In fact, the whole operation was so effective that the starter motor they used for the test could no longer turn the engine on 12V, which is why they went to 24V by adding a second battery.
The injection system and spark plug differences
The guys removed the spark plugs of their four-cylinder engine, boring out and threading their holes to fit diesel injectors. These are connected to an old-school high-pressure diesel injection pump—it’s a radial distributor unit, which is chain-driven by the crankshaft and mounted on a fabricated plate.
Even with starter fluid used heavily and the temperature in the garage being decent, the engine initially refused to start on diesel. However, following multiple diesel injection pump timing adjustments and hot air blown into the intake manifold with a heat gun, the former gas engine woke up to life on diesel. If you’re a fan of engine start-up videos, you’ll love this one.
For now, the remastered Lada engine is barely running. Make no mistake, though: as these mechanics did when converting a diesel engine to run on gasoline, they’ll smooth things out, install the unit in a car (probably another Lada) and take this out for a drive.
Oh, and some years from now, when ICE vehicles are confined to collectors and die-hard enthusiasts, this footage should be even more impressive than it is today.