I did some searching and came up empty. Does anyone know if there are versions of these cheap knock offs that use gasoline? Id rather not have to carry an extra type of fuel besides gasoline
I was participating in a discussion about running these units on gasoline (also the espar D2). Best we can tell there is not a whole of of difference between the gas and diesel versions. The combustion chamber is slightly different, and the initial fuel pump ramp speed during startup is different. Diesel and gas have similar enough energy content, that it should run successfully on gasoline. For 200$ it may be worth a try. Just test it thoroughly.
With espar/eberspacher, the D2 (diesel) and B2(gasoline) (B5 and D5 as well) use the same glow plug, same fuel pump, same blower motor etc. Only the ECU programming, and the combustion chamber are different. The Diesel versions have a mesh screen to hold the flame in place, while the gasoline versions use a couple of smaller tubes and flame holder fins.
I have heard yes, but not yet found any.
If eBay doesn't show them, ask the sellers.
I'm also looking for hydronic / block heater style rather than forced air only.
Authentic Espars are available in both diesel D4 and gas B4 versions. They use the same blower motor, case, gasket, fuel pump, heat exchanger, and glow pin. BUT, they are not the same. The differences are in the burner tube and in the control unit. The diesel uses a slinger system of 2 spinning disks spraying the fuel out between them. The motor shaft is hollow and fuel runs through the shaft to an space between the disks. The gas version uses a fixed jet. They also use different startup procedures and air/fuel ratios. This might seem like a small difference, but it's not. And when playing with volatile fuels like gas you're asking for trouble if you run them in systems designed for diesel.
This is what the diesel burner tube will look like: https://esparparts.com/252113100100-p-25147.html
And this is what the gas burner tube looks like: https://esparparts.com/combustion-burner-p-25157.html
It's not worth trying to run a diesel one on gas. It's dangerous and likely to not work at all. As far as cheap ($100-200) gas versions, I have seen them advertised but you'd have to actually take one apart to tell if it is a misadvertised diesel model or an actual gas version. But for a bit more these guys have them and they are pretty reputable and have good reviews. I'd recommend just running a diesel version off of a 5L-10L tank though, diesel is a much safer fuel and 10L should last a long time.
Those guys also have the block heater style heaters available. Don't know anything about them though.